Dear EarthTalk: Is using nitrogen to inflate my car’s tires really better for the environment than using air? And if so, how? -- Roger Mawdsley, Abbotsville, BC

Whether or not it makes environmental sense to inflate car tires with nitrogen instead of air is a matter of much debate. Proponents of nitrogen say the element is a smart choice for the environment primarily because it leaks from tires at a slower rate than air, so tires stay inflated longer at full capacity, which helps a vehicle attain maximum fuel efficiency, i.e. better gas mileage. According to the Get Nitrogen Institute, a Denver-based non-profit which advocates for replacing the air in our tires with nitrogen, under-inflated tires inadvertently are a big contributor to global warming as they cause drivers to waste fuel.

Although auto experts recommend checking your car’s tire pressure weekly, studies show that the majority of drivers rarely if ever check to see if their tires are properly inflated and usually only add air when a tire is visibly low or beginning to go flat. A recent study by the European division of tire maker Bridgestone found that 93.5 percent of cars in Europe have under-inflated tires, wasting some 2.14 billion gallons of high-priced, polluting fuel every year. Analysts believe that a similar percentage of North Americans are driving around on under-inflated tires as well.

While properly inflated tires certainly promote better fuel efficiency and are thus good for the environment, not everyone is convinced that filling tires with nitrogen instead of plain ol’ air makes a difference. Terry Jackson, who writes the influential “Driving for Dollars” column for the Bankrate.com website, points out that air is composed primarily of, you guessed it, nitrogen; some 78 percent of the regular air you put in your tires is nitrogen, with oxygen making up most of the remainder. “So going to pure nitrogen only squeezes out a small amount of the oxygen molecules that nitrogen proponents argue are so detrimental,” relates Jackson.

Nitrogen proponents may quibble that it’s the oxygen in the mix that causes problems, though, as oxidization can start to degrade the rubber inside tires while corroding the interior of the wheels as well. But Jackson counters that tires and wheels will have been long worn out on the outside before any oxygen-induced interior damage causes them to come apart. Also, he adds that a lot of the leakage from tires happens because the wheel and the tire do not line up perfectly, and air (or nitrogen) escapes accordingly.

Another factor, of course, is cost. Nitrogen-equipped service centers will fill up your tires with nitrogen for something like $10 per tire, which is a far cry from the couple of quarters (if even that) it takes to trigger the air machine at your local gas station. “When it comes down to a dollar decision, it’s hard to argue that spending as much as $40 for nitrogen in a set of tires is a good fiscal move,” writes Jackson.

“Save your money and just keep an eye on your tire pressures,” he concludes.

CONTACTS: Get Nitrogen Institute, www.getnitrogen.org; Bankrate.com, www.bankrate.com

Dear EarthTalk: Backyard fire pits have become the latest must-have gardening feature. How bad are they on the environment? -- Michael O’Laughlin, Tigard, OR

With Fall setting in and the mercury starting to drop, many of us want to extend our time outdoors, and sitting around a backyard fire pit has become one of the most popular means to do so. But even though it may be fun—s’mores anyone?—it is not good for the environment, especially during times when air quality is already poor.

It’s hard to assess the larger impact of backyard fire pits on local or regional air quality, but no one questions the fact that breathing in wood smoke can be irritating if not downright harmful. According to the U.S. Environmental Protection Agency (EPA), so-called fine particles (also called particulate matter) are the most dangerous components of wood smoke from a health perspective, as they “can get into your eyes and respiratory system, where they can cause health problems such as burning eyes, runny nose and illnesses such as bronchitis.”

Fine particles also aggravate chronic heart and lung diseases, and have been linked to premature deaths in those already suffering from such afflictions. As such, the EPA advises that anyone with congestive heart failure, angina, chronic obstructive pulmonary disease, emphysema or asthma should steer clear of wood smoke in general. Children’s exposure to wood smoke should also be limited, as their respiratory systems are still developing and they breathe more air (and air pollution) per pound of body weight than adults.

Geography and topography play a role in how harmful wood smoke can be on a community-wide level. People living in deep, steep-walled valleys where air tends to stagnate should be careful not to light backyard fires during smog alerts or other times when air quality is already poor. Lingering smoke can be an issue even in wide-open areas, especially in winter when temperature inversions limit the flow of air.

The Washington State Department of Ecology reports that about 10 percent of the wintertime air pollution statewide can be attributed to fine particles from wood smoke coming out of wood burning stoves. While a wood stove may be a necessary evil as a source of interior heat, there is no excuse for lighting up a backyard fire pit during times when you could be creating health issues for your neighbors.

Another potential risk to using a backyard fire pit is sparking a forest fire. Some communities that are surrounded by forestland voluntarily institute seasonal burn bans so that residents won’t inadvertently start a forest fire while they are out enjoying their backyard fire pits. If you live in one of these areas, you probably already know it and would be well advised to follow the rules.

If you must light that backyard fire pit, take some precautions to limit your friends’ and family’s exposure to wood smoke. The Maine Bureau of Air Quality recommends using only seasoned firewood and burning it in a way that promotes complete combustion—small, hot fires are better than large smoldering ones—to minimize the amount of harmful smoke. The moral of the story: If you need to burn, burn responsibly.

CONTACTS: U.S. Environmental Protection Agency (EPA), www.epa.gov; Washington State Department of Ecology, www.ecy.wa.gov; Maine Bureau of Air Quality, www.maine.gov/dep/air/.

Dear EarthTalk: How can I measure—and then improve—my overall “carbon footprint?” What are the major areas of one’s daily life that one measures? -- Andy Fusco, Passaic, NJ

With global warming dominating so many headlines today, it’s no surprise that many of us are looking to reduce the amount of carbon dioxide and other greenhouse gases our activities produce.

By assessing how much pollution each of your individual actions generates—be it setting your thermostat, shopping for groceries, commuting to work or flying somewhere for vacation—you can begin to see how changing a few habits here and there can significantly reduce your overall carbon footprint. Luckily for those of us who want to see how we measure up, there are a number of free online carbon footprint calculators to help figure out just where to start changing.

One of the best is the University of California at Berkeley’s Cool Climate Calculator. The free web-based tool takes into account daily driving mileage and grocery and electricity expenses, among other factors, to assign a carbon score, which users can compare to similar households across the 28 largest urban areas in the U.S. Some of the results are surprising. For example, residents of eco-aware San Francisco tend to have bigger carbon footprints than those in more conservative Tampa, Florida. The reason: San Francisco has a higher cost of living and colder, wetter winters (requiring more fossil-fuel derived heat).

Another great carbon footprint calculator is available at EarthLab.com, an online “climate crisis community” that has partnered with Al Gore’s Alliance for Climate Protection and other high-profile groups, companies and celebrities to spread the word that individual actions can make a difference in the fight against global warming. Users just take a three-minute survey and get back a carbon footprint score, which they can save and update as they work to reduce their impact. The site provides some 150 lifestyle change suggestions that will cut carbon emissions—from hanging your clothes to dry to sending postcards instead of letters to taking the bike instead of the car to work a few days a week.

“Our calculator is an important first step in educating people about where they are, then raising their awareness about what they can do to make easy, simple changes that will lower their score and positively impact the planet,” says Anna Rising, EarthLab’s executive director. “Our goal isn’t about convincing you to buy a hybrid or retrofit your house with solar panels; our goal is to introduce you to easy, simple ways that you as an individual can reduce your carbon footprint.”

Other websites, green groups and corporations, including CarbonFootprint.com, CarbonCounter.org, Conservation International, The Nature Conservancy and British Oil Giant BP, among others, also offer carbon calculators on their websites. And CarbonFund.org even allows you to assess your carbon footprint—and then offers you the ability to offset such emissions by investing in clean energy initiatives.

CONTACTS: Cool Climate Calculator, www.berkeley.edu/calculator.html; EarthLab, www.earthlab.com; CarbonFootprint.com, www.carbonfootprint.com; CarbonCounter.org, www.carboncounter.org; Conservation International, www.conservation.org; The Nature Conservancy, www.nature.org; BP, www.bp.com.

Dear EarthTalk: Why are some environmental groups jumping on the immigration issue? What does immigration have to do with the environment? -- Ginna Jones, Darien, CT

What to do about booming legal and illegal immigration rates is one of the most controversial topics on Americans’ political agenda these days. More than a million immigrants achieve permanent resident status in the U.S. every year. Another 700,000 become full-fledged American citizens. The non-profit Pew Research Center reports that 82 percent of U.S. population growth is attributable to immigration.

Meanwhile, the U.S. Census Bureau estimates that U.S. population will grow from 303 million people today to 400 million as early as 2040. While many industrialized nations, including Japan and most of Western Europe, are experiencing population growth slowdowns due to below replacement birth levels and little immigration, the U.S. is growing so fast that it trails only India and China in total numbers.

Advocates for U.S. population stabilization, including some environmental organizations and leaders, fear that this ongoing influx of new arrivals is forcing the nation to exceed its “carrying capacity,” stressing an already overburdened physical infrastructure. David Durham of Population-Environment Balance says that Americans who care about the environment should insist on reducing immigration, to recognize “ecological realities such as limited potable water, topsoil and infrastructure.” He also cites studies showing that a permissive U.S. immigration policy drives up fertility rates in the sending countries “which is the last thing these sending countries need.”

To others the problem is larger than immigration itself. “People don’t just materialize at our border, or at any border,” says John Seager of Population Connection. “When you talk about immigration, you’re talking about the second half of a process that begins when people decide to leave their homes.” And they are usually leaving their homes because of hunger, lack of work, oppression, or any number of other often-desperate reasons. Seager and many others argue that by helping poor nations better address the economic and family planning needs of their citizens, Americans can not only help improve the lot of millions of people living in dire poverty, but also slow down the tide of immigration.

Groups focusing on the immigration-environment nexus are keen to get their voices heard, but many mainstream green groups shun the highly divisive topic, preferring instead to encourage Americans, who are infamous around the world for their huge homes, gas-guzzling cars and extravagant consumption habits, to curb their unsustainable lifestyles, which they see as more fundamental to U.S. environmental problems than population pressures. With just five percent of the world’s people, Americans use a quarter of the world’s fossil fuels, own more private cars than drivers with licenses, and live in homes that are on average 38 percent larger today than they were in 1975. By scaling back, Americans can take a big bite out of pollution, sprawl and other environmental problems, while also setting a good example for those who land in the U.S. every year, lowering the nation’s collective carbon footprint significantly in the process.

CONTACTS: Pew Research Center, www.pewresearch.org; Population-Environment Balance, www.balance.org; Population Connection, www.populationconnection.org.

Dear EarthTalk: What’s the story with animal cloning? Is the meat industry really cloning animals now to “beef up” production? -- Frank DeFazio, Sudbury, MA

Cloning has been controversial ever since Scottish scientists announced in 1996 that they had cloned their first mammal, a sheep they named Dolly. While Dolly lived a painful, arthritic life and died prematurely, possibly due to the imperfections of cloning, industry nonetheless began seeking out ways to capitalize on the new technology. Meanwhile, critics bemoan cloning as immoral and a potential health and safety risk, given the as-yet-unknown consequences of eating foods generated in this way.

In January 2008, the U.S. Food and Drug Administration (FDA) approved the sale of cloned animals and their offspring for food, despite fierce opposition from animal welfare and consumer advocacy groups, environmental organizations, some members of Congress, and many consumers.

“Our evaluation is that the food from cloned animals is as safe as the food we eat every day,” said Stephen Sundlof, the FDA’s chief of veterinary medicine. Meanwhile, the U.S. Department of Agriculture has asked that producers withhold cloned animals, but not their offspring, from the food supply while farmers, processors, grocery stores and restaurants decide how they will respond to the FDA’s landmark decision.

Unsurprisingly, industry groups also argue that beef and milk from cloned animals is safe to consume. They cite a 2005 University of Connecticut study, which concluded that beef and milk from cloned cows did not pose any health or safety threats to people consuming it. But critics say that the oft-cited single study was far too limited to yield any meaningful conclusions: Milk and beef was taken from just six cloned animals, and the study did not take into account whether clones were more susceptible to infection or other microbial problems, as many scientists suspect. Other researchers have noted severe deformities in many cloned animals, as well as a higher incidence of reproductive, immune and other health problems.

The Washington, DC-based Center for Food Safety, in a petition it filed in late 2006, declared: “The available science shows that cloning presents serious food safety risks, animal welfare concerns and unresolved ethical issues that require strict oversight.” The group announced on September 2, 2008 that 20 leading U.S. food producers—including Kraft Foods, General Mills, Gerber/Nestle, Campbell’s Soup and Ben and Jerry’s—will not use cloned animals in their products. “The move by these companies represents a growing industry trend of responding to consumer demand for better food safety, environmental and animal welfare standards,” the group said in making the announcement.

Given the FDA’s green light, consumers’ only hope of avoiding cloned animal products may be to appeal to businesses directly not to peddle such items. The Pennsylvania-based American Anti-Vivisection Society, which opposes all forms of animal research and testing, has mounted a campaign to urge McDonald’s to forego cloned animals in its 30,000 restaurants worldwide.

CONTACTS: U.S. Food & Drug Administration, www.fda.gov; Center for Food Safety, www.centerforfoodsafety.org; American Anti-Vivisection Society, www.aavs.org.

Dear EarthTalk: I’ve read that household cleaners contain cancer-causing toxic ingredients. What should I do, then, to keep my house clean but also safe for my kids? -- Christine Stewart, via e-mail

While much of the research is mixed or inconclusive, a variety of human and animal studies have linked chemicals common in household cleaning products with a wide range of health risks.

The most offensive common ingredients, according to a 2006 study by the University of California Berkeley and Lawrence Berkeley National Laboratory, are ethylene-based glycol, used commonly as a water-soluble solvent in cleaning agents and classified as a hazardous air pollutant by the U.S. Environmental Protection Agency (EPA), and terpenes, a class of chemicals found in lemon, pine and orange oils that can morph into carcinogenic compounds when they mix with ground-level ozone.

Also, chlorine, often labeled as “sodium hypochlorite” or “hypochlorite,” is almost ubiquitous in household cleaners, unfortunately for the inhabitants of many homes. Breathing in its fumes can irritate the lungs, and as such poses a serious health risk to those with pre-existing heart or respiratory problems.

According to the non-profit Cancer Prevention Coalition, some other problematic chemicals found in many household cleaners include crystalline silica, an irritant to the eyes and lungs and a likely carcinogen, and butyl cellosolve, which has been linked to kidney and liver problems and is reportedly toxic to forming cells. The group lists dozens of other potentially dangerous ingredients in household products on the “Hazardous Ingredients in Household Products” PDF available for free on its website.

Gaiam, a leading purveyor of green household and lifestyle items, reports that the average American household contains between three and 25 gallons of toxic materials, mostly in the form of household cleaners filled with petrochemical solvents designed to dissolve dirt. The company bemoans the fact that no law requires cleaning products manufacturers to list ingredients on their labels or to test their products for safety, leaving it up to consumers to make sure their homes are not only clean, but also non-toxic.

Luckily there are plenty of “greener” alternatives now widely available from manufacturers like Gaiam, Earth Friendly Products, Citra-Solv, Ecover, Mrs. Meyers, Sun and Earth, SimpleGreen, Method, and Seventh Generation, among many others. Even big players are getting in on the act. Clorox recently released a new line of home cleaning products under the Green Works label to attract a greening clientele.

For those so inclined, making your own green cleaning solutions is easy and cheap. According to The Green Guide, consumers can “circumvent the armada of commercial cleaners” by keeping handy an ample supply of eight ingredients for nearly every do-it-yourself cleaning job: baking soda, borax, distilled white vinegar, hydrogen peroxide, lemons, olive oil, vegetable-based (liquid castile) soap, and washing soda.

CONTACTS: Cancer Prevention Coalition, www.preventcancer.com; Gaiam, www.gaiam.com; Earth Friendly Products, www.ecos.com; Citra-Solv www.citra-solv.com; Ecover, www.ecover.com; Clorox Green Works, www.greenworkscleaners.com; Mrs. Meyers, www.mrsmeyers.com; Sun and Earth, www.sunandearth.com; Seventh Generation, www.seventhgeneration.com; SimpleGreen, www.simplegreen.com; Method Green Home Care Products, www.methodhome.com.

Dear EarthTalk: What’s the deal nowadays with aerosol spray cans? I thought that the ozone-depleting chemicals used in them were eliminated back in the 1970s. Is this true? If so, what is now used as a propellant? Are aerosols still bad for the ozone layer? -- Sheila, Abilene, TX

The aerosol spray can has a storied history in the United States. First invented in the 1920s by U.S. Department of Agriculture scientists to pressurize insect spray, American soldiers eventually used the technology to help ward off Malaria in the South Pacific during World War II. The aerosol spray cans today, while much smaller and more refined, are direct descendents of those original military grade clunkers. Use of the cans for consumer applications took off during the ensuing decades, until the mid-1970s when ozone depletion first came to the public’s attention.

As a result, consumer aerosol products made in the U.S. have not contained ozone-depleting chemicals—also known as chlorofluorocarbons (CFCs)—since the late 1970s, first because companies voluntary eliminated them, and later because of federal regulations. Clean Air Act and U.S. Environmental Protection Agency (EPA) regulations further restricted the use of CFCs for non-consumer products. All consumer and most other aerosol products made or sold in the U.S. now use propellants—such as hydrocarbons and compressed gases like nitrous oxide—that do not deplete the ozone layer. Aerosol spray cans produced in some other countries might still utilize CFCs, but they cannot legally be sold in the U.S.

According to the industry trade group, the National Aerosol Association, aerosol manufacturers in Europe and other parts of the world initially did not follow the lead of U.S. industry in substituting alternative propellants for CFCs. “The fact that aerosols made in underdeveloped countries may contain CFCs has caused confusion in press reports and in the public mind about the stratospheric ozone/aerosol link,” reports the group. Other countries have also switched out ozone-depleting propellants with non-depleting forms because they signed 1987’s Montreal Protocol, a landmark international agreement signed by 191 countries with the goal of phasing out the production and use of CFCs and other ozone depleting chemicals. Scientists report that that the phase out of the chemicals is now about 90 percent complete.

Of course, just because those deodorant sprays and shaving cream cans aren’t depleting the ozone layer doesn’t mean they are actually good for the environment. They still contain hydrocarbons and/or compressed gases notorious for their contribution to global warming. Every time you hit the button, then, you are raising your carbon footprint, albeit ever so slightly.

Modern-day, CFC-free aerosol sprays also emit volatile organic compounds (VOCs) that contribute to ground-level ozone levels, a key component of asthma-inducing smog. The state of California is now regulating consumer products that contain VOCs—and aerosol sprays are not the only targets: Fingernail polish, perfumes, mouthwashes, pump hair sprays, and roll-on and stick deodorants also emit them.

CONTACTS: National Aerosol Association, www.nationalaerosol.com.

Dear EarthTalk: I’ve heard that increasing eco-awareness around the world has now extended itself to the afterlife, whereby burials can even be “green.” Is that true? -- Mary Lewis, Duxbury, MA

Modern western-world burial practices are arguably absurd, all things considered: We pack our dearly departed with synthetic preservatives and encase them in impenetrable coffins meant to defy the natural forces of decomposition that have been turning ashes to ashes and dust to dust for eons. And in the process we give over thousands of acres of land every year to new cemetery grounds from coast to coast.

According to National Geographic, American funerals are responsible each year for the felling of 30 million board feet of casket wood (some of which comes from tropical hardwoods), 90,000 tons of steel, 1.6 million tons of concrete for burial vaults, and 800,000 gallons of embalming fluid. Even cremation is an environmental horror story, with the incineration process emitting many a noxious substance, including dioxin, hydrochloric acid, sulfur dioxide, and climate-changing carbon dioxide.

But increasing demand for more natural burial practices has spawned changes in the industry, and dozens of funeral homes and cemeteries across the country have started to adopt greener ways of operating. Many of these providers are members of the non-profit Green Burial Council, which works “to make burial sustainable for the planet, meaningful for the families, and economically viable for the provider.”

The organization partners with land trusts, park service agencies and the funeral profession to help consumers get the greenest burial experience possible. Its network of approved providers is committed to reducing the industry’s toxins, waste and carbon emissions. Many of the group’s member cemeteries—you can find a directory on the Green Burial Council’s website—offer clients the option of burying loved ones in more natural landscapes uncluttered by headstones and mausoleums. In place of a traditional headstone, for example, a tree might be planted over the grave.

And instead of conventional wood and steel coffins, clients can bury loved ones in more biodegradable wicker or cardboard, or in a casket made of wood certified as sustainably harvested by the nonprofit Forest Stewardship Council. Advocates of such greener burials say that people take comfort in knowing their bodies will decompose and become part of the cycle of nature.

Likewise, dry ice is becoming a popular, non-toxic alternative to embalming. According to Greensprings Natural Cemetery in Newfield, New York, “No state in the U.S. requires embalming, though some may require it if burial doesn’t take place within a set amount of time—usually 24 or 48 hours.”

Even the practice of scattering ashes at sea has a new wrinkle. Florida-based Great Burial Reef will place urns with cremated remains within 100 percent natural, PH-balanced concrete artificial reefs placed at the bottom of the ocean. And Georgia-based Eternal Reefs will mix your ashes with the cement they use to create “reef balls”—hollow spheres that resemble giant Wiffle balls that are sunk offshore. Loved ones equipped with the GPS coordinates can boat or even dive to visit the site of the remains.

CONTACTS: Green Burial Council, www.greenburialcouncil.org; Forest Stewardship Council, www.fscus.org; Greensprings Natural Cemetery, www.naturalburial.org; Great Burial Reef, www.greatburialreef.com; Eternal Reefs, www.eternalreefs.com.

Dear EarthTalk: I am considering solar panels for my roof to provide heat for my hot water and possibly to do more than that. Are there some kinds of solar panels that are better than others? How do I find a knowledgeable installer? -- Elise, Watertown, MA

What type of solar energy capture system you put on your home depends on your needs. If you want to go full tilt and generate usable electricity from your home’s rooftop—and even possibly contribute power back to the larger grid—tried and true photovoltaic arrays might be just the ticket. A typical installation involves the panels, which are constructed of many individual silicon-based photovoltaic cells and their support structures, along with an inverter, electrical conduit piping and AC/DC disconnect switches.

These systems can cost tens of thousands of dollars to install, and as such may not pencil out for those looking for the cheapest power solution. But the upside is that homeowners with photovoltaic panels on their rooftops can rest assured that as long as the sun shines, they will have power to spare without generating emissions of carbon dioxide and other noxious pollutants.

Qualified solar installers can usually advise clients on which specific types of systems will work best given the specific location of a home. U.S. homeowners can find qualified photovoltaic installers via the website FindSolar.com. And the North American Board of Certified Energy Practitioners (NABCEP) provides a free searchable database of its U.S. and Canadian members specializing in home solar set-ups.

For less demanding applications, such as for heating water for your home or swimming pool, a much simpler (and less expensive) solar thermal system might be all you need. A basic hot water system usually consists of a solar collector—basically a small metal box with a glass or plastic cover and a black copper or aluminum absorber plate inside—tied into the building’s plumbing and electrical works. According to the industry tracker website Solarbuzz, such solar collectors are usually mounted on rooftops.

Professional installers can get your home up and running with a solar thermal system for less than $4,000 in most cases. While the savings in your electric bill may be small, homeowners in it for the long haul will definitely save over time, all the while enjoying the fact that you have lowered your family’s carbon footprint significantly.

Homeowners looking to find out more about residential solar systems should be sure to check out the RealGoods Solar Living Sourcebook, a 600+ page renewable energy “bible” now in its 30th edition. The book features the latest nuts-and-bolts information on how to harvest renewable energy in a variety of ways depending on need. And RealGoods also sells much if not all of the equipment needed.

Another reason to consider going solar in one fashion or another is tax incentives. According to the Database of State Incentives for Renewables and Efficiency (DSIRE), 17 states now offer homeowners some kind of tax rebate or incentive for the purchase and/or installation of solar power equipment of any kind. You can see what if any your state offers by logging onto the dsireusa.org website, where the searchable database is available in its entirety for free.

CONTACTS: Solarbuzz, www.solarbuzz.com; FindSolar.com, www.findsolar.com; NABCEP, www.nabcep.org; RealGoods, www.realgoods.com; DSIRE, www.dsireusa.org.

Dear EarthTalk: Everyone knows we should recycle metal, glass and plastic cans and bottles, but what about all the lids, tops and caps? I see people recycling plastic bottles, for example, with their caps on, but I've always been told to thrown them out. Is that wrong? -- Stefanie Gandolfi, Oakland, CA

Many municipal recycling programs throughout the U.S. still do not accept plastic lids, tops and caps even though they take the containers that accompany them. The reason is that they are not typically made of the same kinds of plastics as their containers and therefore should not be mixed together with them.

“Just about any plastic can be recycled,” says Signe Gilson, Waste Diversion Manager for Seattle-based CleanScapes, one of the west coast’s leading “green” solid waste and recycling collectors, “but when two types are mixed, one contaminates the other, reducing the value of the material or requiring resources to separate them before processing.”

Also, plastic caps and lids can jam processing equipment at recycling facilities, and the plastic containers with tops still on them may not compact properly during the recycling process. They can also present a safety risk for recycling workers. “Most plastic bottles are baled for transport and if they don’t crack when baled, the ones with tightly fastened lids can explode when the temperature increases,” says Gilson.

Some recycling programs do accept plastic caps and lids, but usually only if they are off their containers completely and batched separately. Given the many potential issues, however, most recyclers would rather avoid taking them altogether. Thus it is hard to believe but true: In most locales the responsible consumers are the ones who throw their plastic caps and lids into the trash instead of the recycling bin.

As for metal caps and lids, they, too, can jam processing machines, but many municipalities accept them for recycling anyway because they do not cause any batch contamination issues. To deal with the potentially sharp lid of any can you are recycling (such as a tuna, soup or pet food can), carefully sink it down into the can, rinse it all clean, and put it in your recycling bin.

Of course, the best way to reduce all kinds of container and cap recycling is to buy in large rather than single-serving containers. Does the event you’re holding really require dozens and dozens of 8- to 16-ounce soda and water bottles, many of which will get left behind only partly consumed anyway? Why not buy large soda bottles, provide pitchers of (tap) water and let people pour into re-usable cups?

The same kind of approach can be taken with many if not all of the bottled and canned grocery items we buy routinely for the home. If more people bought in bulk, apportioning out of larger, fewer containers, we could take a huge bite out of what goes into the waste stream.

CONTACTS: CleanScapes, www.cleanscapes.com.

Dear EarthTalk: My body doesn’t tolerate cheese well. Are there dairy-free cheeses that will be easier on my constitution and better for the environment, too? -- Steve Sullivan, Seattle, WA

With some 30 to 50 million Americans suffering from various degrees of lactose intolerance, and an estimated three million of us now eating animal-free (vegan) diets for humane, environmental and/or health reasons, the production of alternatives to dairy products has started to become big business.

But while substitutes for milks and ice creams abound, mostly soy- or rice-based blends that have come a long way since they first appeared on grocery shelves, finding satisfactory alternatives to the many varieties of cheese can be a challenge. But the choices are expanding rapidly.

The first place to look might just be your regular supermarket’s produce section—that’s often where you’ll find Galaxy Foods’ Veggie line of non-dairy cheeses. After all, they are made from soy, a crop. Galaxy’s offerings come shredded, grated, in slices and in hunks. Fans swear they taste just like the real thing. And they are all excellent sources of calcium without cholesterol, saturated/trans-fats or lactose.

Galaxy also offers cheeses made from rice. And while some of both the Rice Brand and Veggie line contain small amounts of cultured milk salt, dried skim milk protein and trace amounts of lactose, Galaxy also make two purely vegan varieties, usually found in the dairy sections of grocery or health food stores.

A few other popular brands made with rice include Rice Slices and Lifetime Low Fat Jalapeno Jack Rice Cheese. Check the shelves of your local organic or natural food market to find one or more to sample.

Another leading producer of dairy-free cheeses is Scotland’s Bute Island Foods. The company began making its own vegan hard cheese alternatives (sold under the Sheese brand name) in 1988, and has since expanded into cream cheese alternatives (Creamy Sheese) as well. From pizzas to sauces to sandwiches to spreads, Bute Island has vegan and lactose-intolerant cheese lovers covered.

Some other soy-based choices that get good reviews include Good Slice Cheddar Style Cheese Alternative (great for sandwiches), vegan-friendly Tofutti Soy Cheese Slices, Follow Your Heart’s Vegan Gourmet (pizza, anyone?), and Teese (it melts with the best of them), among others.

Do-it-yourselfers might want to experiment with making their own non-dairy cheese using ingredients such as tofu and yeast. A quick web search will yield many recipes for making cheese and for using non-dairy cheeses in favorite dishes. Many of the best are collected in Joanne Stepaniak’s The Ultimate Uncheese Cookbook, available in some bookstores as well as from Amazon.com and other online vendors.

With so many good choices, not to mention recipes for home cooked varieties, many a vegetarian may just make the leap into full-fledged vegan eating. And existing vegans can rejoice: French Onion Soup (dairy-free, of course) is back on the menu.

CONTACTS: Galaxy Foods, www.galaxyfoods.com; Bute Island Foods, www.buteisland.com; Follow Your Heart, www.followyourheart.com.

Dear EarthTalk: Can those energy-efficient compact fluorescent light bulbs that are popular now cause headaches because of the flickering they do? I converted my whole house over last fall and both my kids were complaining of headaches on and off. -- Sandy, Eugene, OR

With a switch to energy efficient compact fluorescent (CFL) light bulbs already in full swing in the U.S. and elsewhere—Australia has banned incandescents, Britain will soon, and the U.S. begins a phase-out of incandescents in 2012—more and more complaints have arisen about the new bulbs causing headaches.

Many experts say that the issue is being overblown, however, that there is no scientific evidence that the bulbs cause headaches and that a kind of hysteria has grown out of a small number of anecdotal reports.

Industry experts acknowledge that day-to-day exposure to older, magnetically ballasted long tube fluorescent bulbs found mostly in industrial and institutional settings could cause headaches due to their noticeable flicker rate. The human brain can detect the 60 cycles per second such older bulbs need to refresh themselves to keep putting out light.

However, modern, electronically ballasted CFLs refresh themselves at between 10,000 and 40,000 cycles per second, rates too fast for the human eye or brain to detect. “As far as I’m aware there is no association between headaches and the use of compact fluorescent lamps,” says Phil Scarbro of Energy Federation Incorporated (EFI), a leading distributor of energy efficiency-related products—including many CFLs.

But Magda Havas, an Environmental & Resource Studies Ph.D. at Canada’s Trent University, says that some CFLs emit radio frequency radiation that can cause fatigue, dizziness, ringing in the ears, eyestrain, even migraines. You can test to see if CFLs in your home give off such radiation, she says, by putting a portable AM radio near one that’s on and listening for extra static the closer you get. She says that such electromagnetic interference should also be of concern to people using cell phones and wireless computers.

Sometimes headaches are due to eyestrain from inadequate lighting. When replacing an incandescent bulb with a CFL, pay attention to the lumens, which indicate the amount of light a bulb gives out (watts measure the energy use of a bulb, not the light generated). A 40-watt incandescent bulb can be replaced by an 11-14 watt CFL because the lumen ouput is approximately the same (490); a 100-watt incandescent can be replaced by a 26-29 watt CFL, both providing about 1,750 lumens. If you’re still skeptical, replace a 40-watt incandescent with a 60-watt equivalent 15-19 watt CFL, which will boost lumens to 900.

Another consideration is color temperature (measured in degrees “Kelvin”). CFLs rated at 2,700 Kelvin give off light in the more pleasing red/yellow end of the color spectrum, closer to that of most incandescents. Bulbs rated at 5,000 Kelvin and above (usually older ones) give off a less pleasing white/blue light.

The Environmental Defense website provides a handy chart comparing the watts and lumens of incandescents versus CFLs, along with further discussion about color temperature.

CONTACTS: EFI, www.efi.org; Environmental Defense, www.edf.org/page.cfm?tagid=630.

Dear EarthTalk: How does congestion toll pricing, used in some cities around the world, cut down on vehicle traffic and promote green-friendly public transit? -- Bill Higley, via e-mail

Despite increasing green awareness and steadily rising gasoline prices, Americans and other denizens of the developed world—not to mention millions of new Chinese and Indian drivers hitting the road every week—are loath to give up the freedom and privacy of their personal automobiles. But snarled traffic, longer commute times and rising pollution levels have given city transportation planners new ammunition in their efforts to encourage the use of clean, energy-efficient public transit. One of the newest tools in their arsenal is so-called congestion pricing (also called variable toll pricing), whereby cars and trucks are hit with higher tolls if they access central urban areas at traditionally congested times.

Singapore was the world’s first major city to employ congestion pricing in 1975 when it began charging drivers $3 to bring their vehicles into the city’s central business district. The system has since expanded citywide, with toll rates at several locations changing over the course of a day. Funds generated by the program have allowed Singapore to expand and improve public transit and keep traffic at an optimal flow. Some of the tangible benefits of the program, according to Environmental Defense, include a 45 percent traffic reduction, a 10 miles-per-hour increase in average driving speed, 25 percent fewer accidents, 176,000 fewer pounds of carbon dioxide (CO2) emitted, and a 20 percent increase in public transit usage.

London implemented a similar plan in 2003 that was so successful it was extended to some outlying parts of the city in 2007. Today, drivers pay $13 to bring their vehicles into certain sections of London during peak traffic hours. According to the Victoria Transport Policy Institute, London’s plan has significantly reduced traffic, improved bus service and generated substantial revenues. Environmental Defense says the plan reduced congestion by 30 percent, increased traffic speed by 37 percent, removed 12 percent of pollutants from the air and cut fuel consumption and CO2 emissions by 20 percent.

A 2006 congestion pricing experiment in Stockholm produced similar results, shrinking commute times significantly, reducing pollution noticeably and increasing public transit use during a seven-month test. The day after the trial ended, traffic jams reappeared, so Stockholm voters passed a referendum to reinstate the plan. Today the city has one of the most extensive congestion pricing systems in the world.

Perhaps the next major city to implement congestion pricing will be New York, if Mayor Michael Bloomberg gets his way. In July 2007, the state legislature rejected Bloomberg’s first such proposal—which would have used funds collected to pay for expansions and improvements to the regional public transit system—but ever-increasing congestion and pollution might force lawmakers’ hand in the future.

“A congestion pricing plan is the most cost-effective way to jump-start transit improvements and reduce traffic congestion,” says Wiley Norvell of Transportation Alternatives, one of a handful of groups working with Bloomberg to craft a version of the plan that will fly with state lawmakers. With two-thirds of New Yorkers opposed, it looks like an uphill battle for now, but advocates say passing such rules is inevitable.

CONTACTS: Environmental Defense, www.environmentaldefense.org; Transportation Alternatives, www.transalt.org.

Dear EarthTalk: I’ve read that plastic bottles are not always safe to reuse over and over as harmful chemicals can leach out into the contents. I’m wondering if the same issues plague Tupperware and other similar plastic food storage containers. -- Sylvie, Dawson City, Yukon, Canada

The recent hubbub over plastic containers leaching chemicals into food and drinks has cast a pall over all kinds of plastics that come into contact with what we ingest, whether deserved or not. Some conscientious consumers are forsaking all plastics entirely out of health concerns. But while it is true that exposure to certain chemicals found in some plastics has been linked to various human health problems (especially certain types of cancer and reproductive disorders), only a small percentage of plastics contain them.

According to The Green Guide, a website and magazine devoted to greener living and owned by the National Geographic Society, the safest plastics for repeated use in storing food are made from high-density polyethylene (HDPE, or plastic #2), low-density polyethylene (LDPE, or plastic #4) and polypropylene (PP, or plastic #5). Most Tupperware products are made of LDPE or PP, and as such are considered safe for repeated use storing food items and cycling through the dishwasher. Most food storage products from Glad, Hefty, Ziploc and Saran also pass The Green Guide’s muster for health safety.

But consumers should be aware of more than just a few “safe” brands, as most companies make several product lines featuring different types of plastics. While the vast majority of Tupperware products are considered safe, for example, some of its food storage containers use polycarbonate (plastic #7), which has been shown to leach the harmful hormone-disrupting chemical Bisphenol A (BPA) into food items after repeated uses. Consumers concerned about such risks might want to avoid the following polycarbonate-based Tupperware products: the Rock ‘N Serve microwave line, the Meals-in-Minutes Microsteamer, the “Elegant” Serving Line, the TupperCare baby bottle, the Pizza Keep’ N Heat container, and the Table Collection (the last three are no longer made but might still be kicking around your kitchen).

Beyond BPA, other chemicals can be found in various food storage containers. Containers made out of polyethylene terephthalate (PET or PETE, or plastic #1)—such as most soda bottles—are OK to use once, but can leach carcinogenic, hormone-disrupting phthalates when used over and over again. Also, many deli items come wrapped in plastic made from polyvinyl chloride (PVC, or plastic #3), which can leach cancer-causing dioxins. Swapping foods out of such wraps once the groceries are at home is advisable.

Containers made of polystyrene (PS, or plastic #6, also known as Styrofoam) can also be dangerous, as its base component, styrene, has been associated with skin, eye and respiratory irritation, depression, fatigue, compromised kidney function, and central nervous system damage. Take-out restaurant orders often come in polystyrene containers, which also should be emptied into safer containers once you get them home.

If your head is spinning and you can’t bear to examine the bottom of yet another plastic food storage container for its recycling number, go with glass. Pyrex, for instance, does not contain chemicals that can leach into food. Of course, such items can break into glass shards if dropped. But most consumers would gladly trade the risk of chemical contamination for the risk of breakage any day.

CONTACTS: The Green Guide, www.thegreenguide.com; Tupperware, www.tupperware.com.

Dear EarthTalk: What are the major environmental issues that our next president, be it Obama or McCain, will have to confront? -- Melinda Barnes, via e-mail

Global warming is unquestionably the most pressing environmental issue facing whoever ends up in the White House in January 2009. Not only does climate change impact—and in most cases exacerbate—other environmental problems, it has even wider implications for the economy and society at large. Luckily for all of us, both Barack Obama and John McCain are committed to tackling climate change, although their proposed approaches differ in significant ways.

The non-profit League of Conservation Voters (LCV), America’s leading voice for environmental advocacy within electoral politics, would prefer to see Obama elected president given his environmental track record and plans for the future. While both candidates favor instituting a mandatory “cap-and-trade” program (whereby the federal government allows polluters to trade for the right to emit a reduced overall amount of greenhouse gases), Obama is for more strident cuts. He would like to see the U.S. reduce its greenhouse gas emissions by some 80 percent by 2050, while McCain supports only cutting back by 65 percent. Both candidates have authored legislation in the Senate designed to reduce greenhouse gas emissions, although no such bills have come close to passing.

Even though McCain is by far the most forward-thinking of the original Republican presidential contenders on global warming and the need to take action, LCV still gives him poor marks, only a 24 rating (out of 100) lifetime and zero for 2007. LCV says that McCain missed all 15 critical environmental votes last year and that he “repeatedly clings to outdated policies and flip-flops on core environmental issues.” By comparison, Obama earned a score of 100 in 2007 and has a lifetime LCV rating of 87.

One area where environmentalists take issue with McCain is his support for expanding the role of nuclear power in cutting fossil fuel use. Obama would rather bolster alternative energy sources like wind and solar power that do not have the nasty side effect of radioactive waste in need of storage and disposal. (McCain also supports the development of new renewables, but not to the extent that Obama is willing to commit).

Some of the other hot button environmental issues sure to occupy the next president’s time include: how to best protect the nation’s water resources and wetlands; whether to allow more drilling for oil and natural gas both offshore and within Alaska’s Arctic National Wildlife Refuge; whether to reinstate the Roadless Area Conservation Rule, a Clinton-era law (subsequently overturned by the Bush administration) calling for protection of some 58 million acres of public land from logging; how to meet U.S. commitments on existing environmental laws in international trade agreements; and whether to bring back the so-called “polluter pays” part of the government’s “Superfund” toxic waste clean-up program.

While Obama is clearly the greener candidate on most of these issues, the fact that McCain even takes them seriously—and is committed to any greenhouse gas reductions whatsoever—is a plus for environmental advocates exasperated by eight years of green naysaying by the Bush administration.

CONTACTS: Obama ’08, www.barackobama.com; McCain for President, www.johnmccain.com; League of Conservation Voters, www.lcv.org.

Dear EarthTalk: What’s going on in the music industry with all the CDs and plastic CD holders undoubtedly generating a lot of plastic waste? -- John S., via email

According to the U.S. Environmental Protection Agency (EPA), CDs and DVDs are typically manufactured by combining various mined metals (aluminum, gold, silver and nickel) with petroleum-derived plastics, lacquers and dyes. Given what complicated beasts CDs and DVDs are—products with thin layers of different materials mixed together are nearly impossible to recycle—most municipal recycling program won’t accept them, leaving consumers to fend for themselves in figuring out how to dispose of them. As a result, most discarded discs end up in the trash.

These difficult-to-recycle materials can pollute groundwater and, in turn, contribute to a whole host of human health problems. But the low cost of producing such top-selling consumer items means that replacing them with something greener is not likely anytime soon.

Research has shown that polylactic acid (PLA), a biodegradable plastic-substitute derived from corn and other agricultural wastes, could replace plastic polycarbonate as a disc’s main substrate, but the present high cost of using such a material makes it unlikely to catch on any time soon with those paying to produce mass volumes of CDs and DVDs.

As for jewel cases, most are made out of Polyvinyl Chloride (PVC), an inexpensive petrochemical-based plastic that is notoriously difficult to recycle and has been linked to elevated cancer rates among workers and neighbors where it’s manufactured. Furthermore, when PVC is thrown in with regular recyclables it can contaminate entire batches, ruin equipment and cause human health problems. While cardboard and paper jewel cases may be all the rage among a few record labels—Warner Music Group’s U.S. division, for example, has been using 30 percent post-recycled paper for the packaging in all of its CDs and DVDs since 2005—the high cost and low durability of such alternatives have kept them largely out of the mainstream.

So what’s a conscientious consumer to do? Those willing to pay a small processing fee can send old CDs and DVDs to one of a handful of private companies (such as Washington-based GreenDisk) set up to recycle them into high-quality plastics used in auto parts, office equipment, alarm panels, street lights, electrical cable insulation, jewel cases and other specialized items.

A shift in consumer preferences already underway may be just the thing that will make everyone’s personal collections of music and movies greener. Consumers are already able to download some six million individual digital songs via the 500 or so legal online music services now up and running on the Internet. According to the International Federation of the Phonographic Industry, digital sales now account for some 30 percent of all U.S. music sales and 15 percent globally. And most consumer analysts expect these percentages to grow steadily in the coming years, which is good news for the environment.

CONTACTS: EPA’s “Lifecycle of a CD or DVD,” www.epa.gov/osw/students/finalposter.pdf; GreenDisk, www.greendisk.com; International Federation of the Phonographic Industry, www.ifpi.org.

Dear EarthTalk: I need to replace my old TV. Can you tell me which of the latest models is the greenest? I was told that the flat-screen/plasmas are real energy hogs. What do you recommend?-- Angela Montague, via e-mail

According to The Wall Street Journal’s Rebecca Smith, a 42-inch plasma TV set can draw more power than a large refrigerator, even if the TV is only used a few hours a day. This is partly because many newer models don’t turn off but go into “standby” mode so they can start up fast later with no warm-up period. “Powering a fancy TV and full-on entertainment system—with set-top boxes, game consoles, speakers, DVDs and digital video recorders—can add nearly $200 to a family's annual energy bill,” she adds.

Smith recommends green consumers consider the Liquid Crystal Display (LCD) models, which typically uses less energy than comparable plasma sets. According to the U.S. Environmental Protection Agency (EPA), a 28-inch conventional cathode-ray tube (CRT) set uses about 100 watts of electricity. A 42-inch LCD set might consume twice that amount, while plasma could use five times as much, depending on the model and the programming. For the largest screen sizes (60 inches and up), projection TVs are the most energy efficient, clocking in at 150-200 watts—significantly less than the energy a plasma set would use.

“What scares us is that prices for plasma sets are dropping so fast that people are saying, why get a 42-inch plasma set when you can get a 60-inch or 64-inch one,” says Tom Reddoch of the non-profit Electric Power Research Institute. “They have no idea how much electricity these things consume.”

For its part, the industry is taking some steps to make its products more efficient, and to improve disclosure of energy usage. In June 2008 Sony pronounced its new 32-inch Bravia KDL-32JE1 LCD model “the world’s most energy efficient television.” Slated for sale in Japan in August 2008 for around $1,400, the new set utilizes fluorescent tubes to create higher levels of brightness with less energy consumption, but still delivers large resolution, a high contrast ratio and a wide viewing angle.

Beginning in November 2008, forward-thinking manufacturers will get a little boost from the U.S. government, which will start awarding the most energy efficient new TV sets “Energy Star” labels to help consumers identify greener choices. TVs bearing the Energy Star label must operate at least 30 percent more efficiently than standard models in both stand-by and active modes. Consumers can see which models qualify by visiting the televisions section of the EnergyStar.gov home electronics page. According to the EPA, if all TVs sold in the U.S. met Energy Star requirements, yearly energy savings would top $1 billion and greenhouse gas emissions would drop by the equivalent of taking a million cars off the road.

Of course, the greenest option of all (aside from getting out from in front of that tube and spending more time outdoors) is to keep or repair your existing CRT unit (a digital-to-analog converter will be needed after February 2009 when new signal specifications go into effect). Most CRT sets use less energy than any of the LCD or plasma models, and if it ain’t broke, why fix it? Buying a new TV, even a greener one, only generates more pollution in production and transport, and creates waste in junking the old model.

CONTACTS: U.S. Environmental Protection Agency, www.epa.gov; Energy Star, www.energystar.gov; Electric Power Research Institute, www.epri.com; Sony Corp., www.sony.com.

Dear EarthTalk: I heard that children are reaching puberty at earlier ages now and that it may have to do with environmental toxins and even their TV viewing habits. Can you enlighten? -- Mark Abbot, via e-mail

To say that kids are growing up faster than ever these days may be more than just cliché. Recent studies have shown that children are reaching puberty at younger and younger ages, and researchers are starting to see links between this trend and other societal ills such as ubiquitous pollution and sedentary lifestyles.

In a 2007 report for the Breast Cancer Fund entitled “The Falling Age of Puberty in U.S. Girls: What We Know, What We Need to Know,” ecologist Sandra Steingraber argues that unfettered access to computers and TVs over the last 30 years has led to an increasingly sedentary lifestyle among kids in the U.S. and beyond. Active kids produce more melatonin, a natural hormone that serves as the body’s internal clock and calendar. This could explain why sedentary kids are likely to go through puberty sooner: Their bodies think their decreased melatonin production is a trigger to move into puberty. “[Melatonin is] an inhibitory signal for puberty,” says Steingraber. “The more melatonin you have, the later you go into puberty.”

Of course, sedentary lifestyles are also linked to childhood obesity, a condition that often continues—along with the many health problems that can accompany it—into adulthood. A recent National Health and Nutrition Examination Survey (NHANES) found that, between 2001 and 2004, 17.5 percent of children ages six to 11 were overweight—an effective doubling of obesity rates three decades ago. A study by the non-profit Obesity Society came up with a slightly higher figure—20 percent—with the percentages higher for Hispanic, African-American and Native American children.

Obesity is certainly one factor in the surge in so-called “precocious” adolescence, but chemicals are also thought to play a role. According to Erin Barnes, writing in E – The Environmental Magazine, a study comparing the body mass index of Danish and American girls found that the former group hit puberty a full year later than the latter even though their weights were in the same range. Another study found that wealthy girls in South Africa reach puberty a full year after their African-American counterparts. “Many researchers,” writes Barnes, “are studying the relationship between chemical pollutants like PCBs (polychlorinated bphenyls) and phthalates (commonly used plasticizers) and premature development.”

Some researchers believe that the preponderance of synthetic chemicals in more developed societies are interfering with human endocrine development and essentially “tricking” kids’ bodies into going through puberty prematurely. Also, precocious puberty in girls has been linked to breast cancer, as well as higher rates of drug abuse, violence, unintended pregnancies, problems in school and mental health issues.

“Shortening childhood means a shortening of the time before the brain’s complete re-sculpting occurs,” says Steingraber. “Once that happens, the brain doesn’t allow for complex learning.” She adds that the brain can only build the connections used to learn a language, play a musical instrument or ride a bike before it gets flooded with the sex hormones that come with the onset of puberty.

CONTACTS: Breast Cancer Fund, www.breastcancerfund.org; National Health and Nutrition Examination Survey, www.cdc.gov/nchs/nhanes.htm; Obesity Society, www.obesity.org.

Dear EarthTalk: What green-friendly lawn and garden pesticides are available today? I’m particularly interested in options that won’t harm my cats. -- Nancy Blanchard, via e-mail

Pesticides have greatly boosted agricultural yields over the last half century, so it is no wonder, given the commercial availability of many of these synthetic chemicals, that American homeowners apply 100 million pounds of the stuff each year to make their own gardens grow bigger and faster, too.

But the downside of using such chemicals is that they can poison people and pets as well as backyard wildlife: “Common insecticide ingredients such as 2,4-dichlorophenoxyacetic acid (2,4-D), atrazine and dicamba have been shown to harm mouse embryos at times equivalent to the first week after conception in humans,” says Erica Glasener of The Green Guide. Due to such revelations, home gardeners are fast discovering the benefits of avoiding chemicals in favor of natural, less toxic alternatives.

But before thinking about applying pesticides, gardeners can design (or re-design) their gardens to make the most of native plants that have evolved over eons to thrive in local conditions without synthetic aid or lots of water. Choosing native plants appropriate to your elevation, soil type, drainage and sun exposure will naturally repel many common pests and also reduce the propagation of invasive exotic species.

Similarly, embedding your plants in healthy soil replete with beneficial insects and worms can also help reduce the need for pesticides. Laura Moran of Mainstreet.com suggests that home gardeners compost their vegetable food waste—which is chock full of nutrients that plants love—and mix it into existing soil to give the garden a healthy boost. “Aside from stimulating healthy root development,” she writes, “the addition of rich compost also improves soil texture, aeration and water retention.” It also provides a nice home, she says, for the beneficial bugs that are destroyed along with the bad ones by chemical pesticides.

If pesticides are necessary, there are a handful of organic varieties available. Bacillus thuringiensis (“Bt”) is a naturally occurring bacterium that is lethal to most leaf-eating caterpillars on trees, shrubs, flowers and vegetables. According to gardening writer Jeff Ball, it is harmless to all other insects, animals and humans. It comes in a powder form for use as a dust, or, when diluted with water, as a spray. Organic chemists have formulated varieties of Bt to kill mosquitoes or potato beetles as well.

To control slugs in an environmentally friendly manner, The Green Guide’s Glasener suggests recycling the black cell packs that vegetables and annuals are sold in, and placing them (empty) upside down near the base of plants. “Each morning, check the containers for pests, and if you find any, simply throw the container away with the pests inside,” she says. Another easy slug control method is to use hollowed out grapefruit rinds in a similar manner around the base of plants, disposing of them if they turn up any slugs.

Pet owners may already be familiar with insecticidal soaps used to control fleas. Some of these soaps can also be used in the garden to repel insects. For more information, consult a local nursery specializing in organic methods and native plants. Find one near you via the free online Native Plants Nursery Directory.

CONTACTS: The Green Guide, www.thegreenguide.com; MainStreet.com, www.mainstreet.com; Native Plants Nursery Directory, www.plantnative.org/national_nursery_dir_main.htm.

Dear EarthTalk: What’s going on with all the cases of autism cropping up and no one seems to know why? It stands to reason it must be something (or some things) environmental, yet every study allegedly turns up no conclusion? What are the possible causes? -- Jessica W., Austin, TX

No doubt about it, autism rates have skyrocketed in the U.S. and beyond in recent years. According to the Centers for Disease Control and Prevention, the disease affects one in every 150 children born today in the U.S., up from one in 500 as recently as just 10 years ago. It’s become the fastest-growing developmental disability—more prevalent than childhood cancer, juvenile diabetes and pediatric AIDS combined—and it continues to grow at a rate of 10 to 17 percent per year.

While researchers think there is a genetic component to autism, they also believe environmental factors are playing a role in its recent increase. Environmental mercury and other heavy metal exposure, contaminated water, pesticides, a greater reliance on antibiotics—and even extensive television viewing by very young children—may be factors in mounting autism rates. Researchers at the American Academy of Pediatrics and other institutes have also identified flame retardants as possible culprits.

Vaccines containing the mercury preservative thimerosal (now mostly removed from the market) have long been blamed for causing autism, but scientific links are inconclusive. In lieu of a smoking gun, a more complex picture of autism’s environmental causes is now emerging.

Some researchers are focusing on the role of food in a young child’s development. Many autistic children suffer from digestive diseases or have genetic dispositions rendering them unable to naturally rid their bodies of toxins. As such, exposure to heavy metals, pesticides, contaminated water and even processed food could have a devastating cumulative effect, some researchers think. According to Brian MacFabe, a researcher at the University of Western Ontario who has studied autism triggers in rats, simple changes such as removing wheat and dairy from the diet could potentially bring about improvements.

Groups such as the nonprofit Healthy Child Healthy World say it’s about time researchers are looking at environmental factors. “Whatever triggered this current autism epidemic...autistic kids clearly need extra protection from further environmental assault,” the group writes on its blog. They advise parents to be vigilant about the industrial cleaners used in school buildings and the pesticides sprayed on playing fields, where kids spend 25 to 30 hours per week. They and other groups are also looking at the role of untested chemicals in common cleaning products: phthalates, glycol ethers and other known toxins.

Others wonder if a collective “nature deficit disorder” among children plays a factor in rising autism rates. Outdoor exposure has long been associated with healthier cognitive functioning in children, with reduction in Attention Deficit Disorder symptoms and greater emotional capacity. But new findings suggest it could impact autism, too. Last year, Cornell University researchers found higher rates of autism in counties where more households subscribed to cable and children under the age of three regularly watched TV. The Amish, with almost no exposure to TV, have little evidence of autism, notes the study.

CONTACTS: CDC Autism Information Center, www.cdc.gov/ncbddd/autism; Healthy Child Healthy World, www.healthychild.org.

Dear EarthTalk: Recent NASA photos showed the opening of the Northwest Passage and that a third of the Arctic’s sea ice has melted in recent. Are sea levels already starting to rise accordingly, and if so what effects is this having? -- Dudley Robinson, Ireland

Researchers were astounded when, in the fall of 2007, they discovered that the year-round ice pack in the Arctic Ocean had lost some 20 percent of its mass in just two years, setting a new record low since satellite imagery began documenting the terrain in 1978. Without action to stave off climate change, some scientists believe that, at that rate, all of the year-round ice in the Arctic could be gone by as early as 2030.

This massive reduction has allowed an ice-free shipping lane to open through the fabled Northwest Passage along northern Canada, Alaska and Greenland. While the shipping industry—which now has easy northern access between the Atlantic and Pacific oceans—may be cheering this “natural” development, scientists worry about the impact of the resulting rise in sea levels around the world.

With about a third of the world’s population—and 25 percent of Americans—living within 300 feet of an ocean coastline, sea level rise is a big deal. According to the Intergovernmental Panel on Climate Change, made up of leading climate scientists, sea levels have risen some 3.1 millimeters per year since 1993.

The World Wildlife Fund (WWF) reports that low-lying island nations, especially in equatorial regions, have been hardest hit by this phenomenon, and some are threatened with total disappearance. Rising seas have already swallowed up two uninhabited islands in the Central Pacific. On Samoa, thousands of residents have moved to higher ground as shorelines have retreated by as much as 160 feet. And islanders on Tuvalu are scrambling to find new homes as salt water intrusion has made their groundwater undrinkable while increasingly strong hurricanes and ocean swells have devastated shoreline structures.

WWF says that rising seas throughout tropical and sub-tropical regions of the world have inundated coastal ecosystems, decimating local plant and wildlife populations. In Bangladesh and Thailand, coastal mangrove forests—important buffers against storms and tidal waves—are giving way to ocean water.

Unfortunately, even if we curb global warming emissions today, these problems are likely to get worse before they get better. According to marine geophysicist Robin Bell of Columbia University’s Earth Institute, sea levels rise by about 1/16” for every 150 cubic miles of ice that melts off one of the poles.

“That may not sound like a lot, but consider the volume of ice now locked up in the planet’s three greatest ice sheets,” she writes in a recent issue of Scientific American. “If the West Antarctic ice sheet were to disappear, sea level would rise almost 19 feet; the ice in the Greenland ice sheet could add 24 feet to that; and the East Antarctic ice sheet could add yet another 170 feet to the level of the world’s oceans: more than 213 feet in all.” Bell underscores the severity of the situation by pointing out that the 150-foot tall Statue of Liberty could be completely submerged within a matter of decades.

CONTACTS: Intergovernmental Panel on Climate Change (IPCC), www.ipcc.ch; WWF, www.panda.org; Earth Institute at Columbia University, www.earth.columbia.edu.

Dear EarthTalk: What’s available now in lawnmowers that are easier on the environment? My yard is too big for one of those “reel” mowers, and I’m no longer a spring chicken, so I have to buy something that runs on more than human power. What’s out there? -- Joel Klein, Albany, NY

According to the U.S. Environmental Protection Agency (EPA), traditional gas-powered lawnmowers are a public nuisance to say the least. Using one of them for an hour generates as many volatile organic compounds—dangerous airborne pollutants known to exacerbate human respiratory and cardiovascular problems—as driving a typical car for 350 miles. The EPA estimates that, with some 54 million Americans mowing their lawns on a weekly basis, gas lawnmower emissions account for as much as five percent of the nation’s total air pollution. Beyond that, homeowners spill some 17 million gallons of gasoline every year just refueling their lawnmowers.

So what’s a green-minded property owner to do about keeping the grass down? Go electric, of course!

Electric mowers, which either plug into a wall outlet via a long cord or run on batteries charged up from the grid, create no exhaust emissions and run much cleaner than their gas-powered counterparts. They also need less maintenance, with no spark plugs or belts to worry about, and are easier to use, as they tend to be smaller and come with push-button starters. The icing on the cake might be the fact that electric mowers are cheaper to run, using about as much electricity as an ordinary toaster. Most electric mower owners spend about $5 a year on electricity to keep their grass trimmed just right. The non-profit Electric Power Research Institute reports that replacing half of the 1.3 million or so gas mowers in the U.S. with electric models would save the equivalent amount of emissions of taking two million cars off the road.

But going electric has some minor trade-offs. Electric mowers tend to cost up to $150 more than their gas-powered counterparts, and the plug-in varieties can only go 100 feet from the closest outlet without an extension cord. And the cordless models last only 30-60 minutes on a charge, depending on battery size and type, though that’s plenty sufficient for the average lawn (just remember to re-charge it in time for the next mow).

And, of course, just because electric mowers don’t consume fossil fuels or spew emissions directly doesn’t mean they are totally green-friendly. Most people derive their household electricity from coal-fired power plants, the dirtiest of all energy sources. Of course, running an electric mower on electricity generated from clean and renewable sources (solar, wind or hydro power) would be the greenest of all possibilities, and those days may be upon us soon.

For those ready to take the electric mower plunge, the Greener Choices website, a project of Consumer Reports, gives high marks to Black & Decker’s corded ($230) and cordless ($400) models for their efficiency, reliability and ease-of-use. Corded models from Worx and Homelite (both around $200) also fared well, along with cordless offerings from Craftsman, Homelite, Remington and Neuton ($300-450).

CONTACTS: Black & Decker, www.blackanddecker.com; Remington, www.remingtonpowertools.com; Homelite, www.homelite.com; Worx, www.worxpowertools.com; Neuton, www.neutonpower.com; Greener Choices, www.greenerchoices.org.

Dear EarthTalk: I really want to eat healthy and organic but am constantly traveling and on the go. How can I eat fast food without having to always end up at McDonalds and Burger King? -- Dylan Baker, Seattle, Washington

The latest trend in fast food is healthy and organic, and luckily for conscious consumers, several chains offering just such fare are taking root in different parts of the U.S. One of the leaders of this small but scrappy pack of fast food upstarts is O’Naturals. The small chain currently runs two stores of its own in Maine (Falmouth and Portland) and one in Acton, Massachusetts, and franchises out additional locations in Kansas and Florida. O’Naturals’ menu contains lots of vegetarian-friendly items, including “build-your-own” flatbread sandwiches, salads, noodle stir-frys and soups. The meat the restaurant does serve is grass-fed and hormone-free, while the chickens are free-range and the Alaskan salmon is wild.

Another healthy option is EVOS, which currently runs five “quick-casual” restaurants in Florida and is planning a major expansion into the western U.S. Vegetarians can rejoice in the chain’s wide selection of vegetarian and vegan items. While its hormone- and antibiotic-free burgers are still only about as healthy as red meat gets, their soy burger satisfies without the guilt or the cholesterol. Also, EVOS uses organic field greens in its wraps and salads, organic milk in its milkshakes, and fresh fruit in its smoothies. Additionally, the restaurant air-bakes its fries and other typically deep-fried items to keep the fat content as much as 70 percent lower than the same kinds of foods found elsewhere.

Meanwhile, Seattle-based Organics-To-Go, with five locations in Washington and California, lays out a wide array of “grab-and-go” organic and natural foods so customers can make up their own meals out of a cornucopia of healthy choices. Other fast food alternatives offering lots of health (as well as vegetarian and vegan) options include Au Bon Pain, Bruegger’s Bagels, Noah’s Bagels, and World Wraps, while Subway and Quizno’s alike can be good options for those willing to study the menu carefully.

Even though many alternatives exist, it is hard to beat the reach of the major fast food chains, several of which are making small steps toward healthier menus and will undoubtedly continue to do so if consumers bite. McDonald’s, KFC, Burger King and Wendy’s have reduced or eliminated trans-fats. Burger King now offers a veggie burger, and McDonald’s is testing one in California. Taco Bell offers many non-meat options, including a bean and cheese burrito, a veggie fajita wrap, and a 7-layer burrito, which can be had without the cheese and sour cream. Carl’s Jr. also has many tasty and healthy vegetarian options despite an otherwise standard fast-food menu. Vegetarians and vegans looking for more ideas about what to eat when time is of the essence should consult any number of websites with pages devoted to the topic, including Vegetarian-Restaurants.net, VegCooking, FitWise and Vegetarian Resource Group.

And remember, nothing beats seeking out local restaurants when you’re on the road, to soak up some of the local culture. And with trends as they are it shouldn’t be too difficult to find many that do serve healthy menus—just not quite as fast as “fast food” but probably fast enough.

CONTACTS: O’Naturals, www.onaturals.com; EVOS, www.evos.com; Vegetarian-Restaurants.net, www.vegetarian-restaurants.net; VegCooking, www.vegcooking.com; FitWise, www.fitwise.com; Vegetarian Resource Group, www.vrg.org.

Dear EarthTalk: Are sunscreens safe? Which ones do you recommend that will protect my skin from the sun and not cause other issues? -- Bettina E., New York, NY

Getting a little sunshine is important for helping our bodies generate Vitamin D, an important supplement for strong bones, and f or regulating our levels of serotonin and tryptamine, neurotransmitters that keep our moods and sleep/wake cycles in order. Like anything, though, too much sun can cause health issues, from sunburns to skin cancer. For those of us spend more time in the sun than doctors recommend—they say to stay indoors between 11 AM and 3 PM on sunny days to be safe—sunscreens can be lifesavers.

Getting too much sun is bad because of ultraviolet radiation, 90 percent of which comes in the form of Ultraviolet A (UVA) rays that are not absorbed by the ozone layer and penetrate deep into our skin. Ultraviolet B (UVB) rays make up the rest. These rays are partially absorbed by the ozone layer (which makes preserving the ozone layer crucial for our health), and because they don’t penetrate our skin as deeply, can cause those lobster-red sunburns. Both types of UV rays are thought to cause skin cancer.

Yet while most sunscreens block out at least some UVB radiation, many don’t screen UVA rays at all, making their use risky. According to the non-profit Environmental Working Group (EWG), by far most of the commercially available sunscreens do not provide adequate protection against the sun’s harmful UV radiation and may also contain chemicals with questionable safety records.

In all, 84 percent of the 831 sunscreens EWG tested did not pass health and environmental muster. Many contained potentially harmful chemicals like Benzophenone, homosalate and octyl methoxycinnamate (also called octinoxate), which are known to mimic naturally occurring bodily hormones and can thus throw the body’s systems out of whack. Some also contained Padimate-0 and parsol 1789 (also known as avobenzone), which are suspected of causing DNA damage when exposed to sunlight. Furthermore, EWG found that more than half the sunscreens on the market make questionable product claims about longevity, water resistance and UV protection.

As a result, EWG has called on the U.S. Food & Drug Administration (FDA) to establish standards for labeling so consumers have a better idea of what they may be buying. In the meantime, consumers looking to find out how their preferred brand stacks up can check out EWG’s online Skin Deep database, which compares thousands of health and beauty products against environmental and human health standards.

The good news is that many companies are now introducing safer sunscreens crafted from plant- and mineral-based ingredients and without chemical additives. Some of the best, according to Skin Deep, are Alba Botanica Sun’s Fragrance-Free Mineral Sunscreen, Avalon Baby’s Sunscreen SPF 18, Badger’s SPF 30 Sunscreen, Burt’s Bees’ Chemical-Free Sunscreen SPF 15, California Baby’s SPF 30, Juice Beauty’s Green Apple SPF 15 Moisturizer, and Kabana’s Green Screen SPF 15. Natural foods markets stock many of these, or they can be found online at websites like Sun Protection Center and Drugstore.com.

CONTACTS: Environmental Working Group, www.ewg.org; Skin Deep Cosmetic Safety Database, www.cosmeticsdatabase.com; Sun Protection Center, www.sunprotectioncenter.com, Drugstore.com, www.drugstore.com.

Dear EarthTalk: What initiatives are taking place on college campuses to reduce the footprints of these large users of energy and other resources? -- Shawna Smith, Hamilton, NY

Microcosms of the world at large, college campuses are great test beds for environmental change, and many students are working hard to get their administrations to take positive action. The initiatives that are emerging are models for the larger society, and the students pushing for them will be taking these lessons with them, too, as they enter the work force after graduation.

Foremost on the minds of green-leaning students today is global warming, and many are joining hands to persuade their schools to update policies and streamline operations so that their campuses can become part of the solution. Largely a result of student efforts, for example, nearly 500 U.S. colleges and universities have signed the American College and University Presidents (ACUP) Climate Commitment.

This agreement requires schools to put together a comprehensive plan to go “carbon neutral” in two years of signing. (Carbon neutral means contributing no net greenhouse gases to the atmosphere either by not generating them in the first place or by offsetting them somehow, such as through tree-planting or by buying “offsets” from companies that fund alternative energy projects.)

ACUP also commits schools to implementing two or more tangible (and easily implemented) policies right away, such as improving waste minimization and recycling programs, reducing energy usage, providing or encouraging public transportation to and from campus (and switching campus buses over to bio-diesel fuel), constructing bicycle lanes, and implementing green building guidelines for any new construction.

Signatory schools also pledge that they will integrate sustainability into their curricula, making it part of the educational experience.

One place where students are forcing green changes on campus is the dining hall. According to the Sustainable Endowments Institute’s 2007 report card, which looks at environmental initiatives at the 200 colleges and universities with the largest endowment assets in the U.S. and Canada, 70 percent of such schools now “devote at least a portion of food budgets to buying from local farms and/or producers,” while 29 percent earned an “A” in the “food and recycling” category. Yale University even has organic gardens that are student-run and that supply an on-campus farmer’s market for use by campus food services, the local community and students alike.

Another area where college campuses are leading the way is in water conservation. Colleges consume huge quantities of water in dormitories, cafeterias, at athletic facilities and in maintaining their rolling green grounds. According to Niles Barnes of the Association for the Advancement of Sustainability in Higher Education (AASHE), most of the 3,800 institutions of higher education in the U.S. have engaged in some sort of water-saving program. Low-water-volume toilets and urinals, as well as low-flow showerheads and faucets, are “pretty much standard practice across U.S. colleges today,” says Barnes.

CONTACTS: ACUP, www.presidentsclimatecommitment.org; Sustainable Endowments Institute, www.endowmentinstitute.org; AASHE, www.aashe.org.

Dear EarthTalk: What is the status of wetlands in North America? Years ago I remember that wetlands loss, due to development and sprawl, was accelerating fast, but I haven’t heard much on the topic of late.-- John Mossbarger, La Jolla, CA

Wetlands serve as primary habitat for thousands of wildlife species—from ducks to beavers to insects—and form an important ecosystem link between land and water. They also play a key role in maintaining water quality, as they filter out agricultural nutrients and absorb sediments so that municipal water supplies don’t have to. On and near shorelines, wetlands provide a natural buffer against storm surges and rising floodwaters, helping to disperse and absorb excess water before it can damage life and property.

The eradication of wetlands in the so-called New World began when white settlers, intent on taming the land, started developing homesteads and town sites throughout what was to become the United States and Canada. Researchers estimate that at the time of European settlement in the early 1600s, the land that was to become the lower 48 U.S. states had 221 million acres of wetlands. By the mid-1980s, following another great period of loss after World War II when army engineers drained huge swaths of formerly impenetrable marshes and swamps, the continental U.S. had only 103 million wetland acres remaining.

Across the U.S. and Canada, the vast majority of wetlands—about 85 percent—have been destroyed in the name of agricultural expansion. Other major factors include road building, residential development, and the building of large facilities like shopping malls, factories, airports and, ironically, reservoirs.

But growing awareness about the importance of wetlands has led to new regulations aimed at protecting those that remain. A variety of state and federal programs, such as the U.S. Department of Agriculture’s Wetland Reserve Program (whereby landowners voluntarily protect, restore and enhance wetlands on their own private property), have been effective in stemming the tide of wetlands loss. During the 1990s the rate of wetlands loss in the U.S. declined by some 80 percent over previous decades. But the nation is still losing upwards of 50,000 wetland acres per year, according to the U.S. Fish & Wildlife Service.

The issue is of even greater concern in Canada, which harbors a quarter of the world’s remaining wetlands in its northern boreal forests. According to Natural Resources Canada, fully 14 percent of Canada’s total land mass is in the form of wetlands. Researchers believe that about 50 million acres of wetlands have been lost in Canada since European settlement. Underscoring the correlation between urbanization and wetlands loss, less than .2 percent of Canada’s wetlands lie within 25 miles of major urban centers today.

On the global level, 158 governments are signatories to the 1971 Ramsar Convention on Wetlands, an international treaty that provides a framework for international cooperation in the conservation and wise use of wetlands. Some 1,743 wetland sites—totaling almost 400 million acres—have been protected as “Wetlands of International Importance” under the terms of the treaty. Although the Ramsar treaty can do little to stop illegal or legal draining of wetlands, its very existence highlights how seriously the majority of the world’s countries take protecting land formerly thought of as God-forsaken and useless.

CONTACTS: Wetlands Reserve Program, www.nrcs.usda.gov/Programs/WRP/; Natural Resources Canada, www.nrcan-rncan.gc.ca; Ramsar Convention on Wetlands, www.ramsar.org.

Dear EarthTalk: My old computer finally bit the dust and I am in the market for a replacement. Are there any particularly “green” computers for sale these days? -- Brian Smith, Nashua, NH

Thanks in part to pressure from non-profits like Greenpeace International—which has published quarterly versions of its landmark “Guide to Greener Electronics” since 2006—computer makers now understand that consumers care about the environmental footprints of the products they use.

The latest version of Greenpeace’s guide gives high marks to Toshiba, Lenovo, Sony and Dell for increasing the recyclability of their computers and reducing toxic components and so-called “e-waste” (refuse from discarded electronic devices and components). The group also credits Apple, HP and Fujitsu for making strides toward greener products and manufacturing processes, but emphasizes that even such top ranked companies have lots of room for improvement when it comes to the environment.

PC Magazine, the leading computer publication for consumer and business users, recently assessed dozens of personal computers according to environmental standards it developed in-house based on energy efficiency, recyclability and the toxicity of components. The publication also factored in various “green” certification schemes such as the U.S. Environmental Protection Agency’s EnergyStar program, the European Union’s Restriction of Hazardous Substances (RoHS) directive, Taiwan’s Greenmark and the computer industry’s own Electronic Products Environmental Assessment Tool (EPEAT).

The top choices for green desktop computers, according to PC, are Apple’s Mac Mini, Zonbu’s Desktop Mini, HP Compaq’s 2710p and dc7800, Lenovo’s ThinkCentre a61e, and Dell’s OptiPlex 755. As for laptops, the greenest current models include Dell’s Latitude D630, the Everex Zonbu, Fujitsu’s LifeBook S6510, and Toshiba’s Tecra A9-S9013.

Perhaps more important than the green-ness of your new computer is what you do with the old one. Stuffing it into the trash or setting it out for curbside pick-up may be the worst thing you can do with an outdated computer, as heavy metals and other toxins inevitably get free and get into surrounding soils and water. If the machine still works, donate it to a local school that can put it to use, or to Goodwill or the Salvation Army, either of which can re-sell it to help fund their programs. Another option is to donate it to the National Cristina Foundation, which places outdated technology with needy non-profits.

Once you’ve gotten rid of an old computer and outfitted yourself with a spiffy new green one, you might just want to score a few green accessories. Brooklyn, New York’s Verdant Computing, which bills itself as a purveyor of “the greenest computer products on the web,” sells remanufactured ink and toner cartridges, laptop cases made from recycled plastic, GreenDisk CDs packaged in recycled plastic jewel cases, solar-powered MP3 accessories, energy-saving printers and even a software program, GreenPrint, which modifies the print programs on your computer to economize on paper and ink/toner use. Verdant also has most products shipped to consumers directly from the manufacturers to save re-shipping.

CONTACTS: Greenpeace International, www.greenpeace.org; PC Magazine, www.pcmag.com; National Cristina Foundation, www.cristina.org; Verdant Computing, www.verdantcomputing.com.

Dear EarthTalk: Are there any efforts underway to green the air travel industry? It seems to me that it must be one dirty business from a pollution standpoint. -- Elias Corey, Seattle, WA

Environmental battles over the siting and expansion of airports are as old as the air travel industry itself, but only in recent years have the airlines themselves been under pressure to go green.

And there’s no time like the present for the industry to take some action: Air pollution from commercial jets is a growing concern among scientists, as is air travel’s role in climate change because of the more acute warming effect of emissions when they are disbursed so much closer to the upper atmosphere.

According to the Royal Commission on Environmental Pollution, an independent group of scientists that advises the British government, emissions from aircraft will likely be one of the major contributors to global warming by the year 2050. According to USA Today, on a flight from New York to Denver, a commercial jet generates between “840 to 1,660 pounds of carbon dioxide per passenger. That’s about what an SUV generates in a month.”

Despite still gloomy times for the industry post-9/11, a few are actually responding to the call. Virgin is blazing new trails as part of a $3 billion investment in energy efficiency. The company is experimenting with biodiesel and ethanol—fuels derived from crops—and has invested hundreds of millions of dollars in ethanol-related businesses. But don’t expect to ride on a biofuel-powered jet anytime soon.

Airplane makers are getting in on the act, too. Boeing successfully flew the world’s first hydrogen-powered, fuel cell airplane in April 2008. A company spokesperson called the plane—a small one-seater—“full of promises for a greener future.” Boeing is working to develop a commercial version, but uncertainties about hydrogen production and distribution put this advancement well into the future, too.

So what can consumers do to fly greener today? Sharon Beaulaurier of GreenLight magazine suggests choosing airlines with newer, more fuel-efficient fleets such as JetBlue, Singapore Airlines or Virgin. She adds that direct flights are better than those with stopovers, as frequent take-offs and landings use more fuel than when the planes are cruising. She also recommends avoiding airlines and airports with bad track records for delays, which leave planes idling and spewing greenhouse gases for hours unnecessarily.

The National Air Traffic Controllers Association (NATCA) runs AvoidDelays.com, which helps fliers choose airlines and airports based on on-time departures. Airlines with poor records include American, Atlantic Southeast, ExpressJet, Mesa and United, according to NATCA, which also calls Chicago’s O’Hare, New York’s LaGuardia, Newark, Philadelphia and San Francisco the worst airports for catching on-time flights.

Meanwhile, the European Union wants to require airlines touching down in Europe to participate in continent-wide carbon reduction programs already in place. Backers hope it will cut Europe’s exponential growth in airline emissions in half by 2020. Some carriers oppose the plan and are fighting it in court.

CONTACTS: Virgin Group, www.virgin.com; Boeing, www.boeing.com; AvoidDelays.com, www.avoiddelays.com.

Dear EarthTalk: How can I find out which seafood to avoid if I am concerned about lessening my impact on the environment and avoiding consuming unhealthy pollutants? -- Pat Kelly, Seattle, WA

Several decades ago a fish-centric diet was considered to be not only healthy but also environmentally friendly. But today those of us who eat a lot of fish may not be doing ourselves or the environment any favor. The two major concerns are overfishing and pollution.

Demand for low-calorie, protein-rich fish has grown tremendously alongside increases in world population. At the same time, the technologies employed for catching seafood have improved to the point that the commercial fishing industry has essentially stripped the ocean of its once teeming fish populations. One recent analysis concluded that only 10 percent of the large predatory fish that once roamed the world’s oceans are left, due to overzealous sport and commercial fishing. Another study concluded that three-quarters of the world’s fisheries are either fully fished or overfished.

Pollution from industrial, agricultural and other everyday activities like electricity generation and automobile driving has also taken a serious toll on the health of the remaining fish species. Scientists routinely find unsafe levels of mercury, PCBs, dioxins, pesticides and other harsh toxins in the fat, internal organs and even muscle tissue of many different kinds of fish. These contaminants are then passed on up the food chain to our dinner plates.

According to Seafood Watch, a project of the Monterey Bay Aquarium that works to educate the public about the seafood crisis, consumers can make a difference by getting educated so as to make smart choices about what seafood to avoid. Consumers can download and print out free Seafood Watch pocket guides to the “best choices” across six different regions of the U.S.—after all, what’s abundant and sustainably harvested in your area may not be the same for someone across the country.

Another convenient way to get the low-down on the fish you may be contemplating buying at the grocer or a restaurant is to text “30644” with the message “FISH,” followed by the name of the specific fish in question. In a few seconds, an automated response will come back from the non-profit Blue Ocean Network’s FishPhone service with information on the status of the fish in question—and alternatives, should Blue Ocean consider the fish an undesirable choice.

The basic skinny on fish consumption is that if you like it, you should eat it, but responsibly—that means in moderation and armed with the proper knowledge of which types of fish to buy and which to avoid.

For those looking to cut down on or eliminate seafood from their diets but still gain the health benefits of eating fish, plenty of alternatives exist. As most vegetarians know, beans, tofu and many nuts can be significant alternative sources of protein. And walnuts, flaxseed and hemp oil/seeds are all rich in the Omega-3 fatty acids common in many fish and thought to help ward off heart disease, cancer, macular degeneration (age-related blindness), arthritis and inflammatory disorders.

CONTACTS: Seafood Watch, www.mbayaq.org/cr/seafoodwatch.asp; FishPhone, www.fishphone.org.

Dear EarthTalk: What makes those so-called “new urbanism” housing developments popping up around the U.S. more environmentally friendly than regular old suburban neighborhoods? -- Rusty Spinoza, Galveston, TX

The husband-and-wife team of town planners Andrés Duany and Elizabeth Plater-Zyberk are typically credited as the founders of new urbanism, a style of community design that embraces mixed use (commercial and residential) development in pedestrian-friendly and green space-rich neighborhoods—much like the old neighborhoods many baby-boomers remember before suburban sprawl made us all slaves to our cars.

Duany and Plater-Zyberk formulated their new urbanism principles while living in one of the Victorian neighborhoods of New Haven, Connecticut while they attended graduate school in architecture at Yale. Their neighborhood included corner shops, front porches and a variety of attractive and well-designed housing and commercial structures—planting the seed of an idea that has now swept the U.S. and beyond.

The prototypical new urbanist community is Florida’s Seaside, which Duany and Plater-Zyberk began designing in 1979 for the 80-acre coastal parcel’s developer, Robert S. Davis. Their plan took the best elements of a handful of graceful southern cities like Key West, Charleston and Savannah to create a community based on the tried-and-true concept of walkable, self-contained neighborhoods. Besides 300 homes, Seaside contains a school, a town hall, an open-air market, a tennis club, a tented amphitheater and a post office—everything anyone could ever need in a town, and all within a five minute walk.

According to the non-profit Smart Communities Network, Seaside works as a community because of its design: “Mandatory porches are set close enough to walkways to enable porch sitters and passersby to communicate without raising their voices…. The streets are all interconnected; creating a network that eliminates ‘collector’ routes and reduces congestion. Walkways crisscross the development to encourage walking and biking, while narrow streets serve to reduce traffic speed.” Building fronts are a uniform distance from the curb and all streets are tree-lined to further the community’s “sense of place.”

Other examples of new urbanist communities include: Stapleton on the outskirts of Denver, Colorado; Seabrook on the southern coast of Washington State; Melrose Arch in Johannesburg, South Africa; Alta de Lisboa near Lisbon, Portugal; and Jakriborg in southern Sweden. Meanwhile, the idea has caught on in New Orleans, where developers are styling new communities in the wake of Hurricane Katrina based in part on the principles of new urbanism.

According to the website NewUrbanism.org, being green is central to the concept of new urbanism, where houses tend to be compact and on small lots. And many developers are incorporating green building design and alternative energy generation into their plans for these communities. Furthermore, proponents say that building densely settled, walkable communities instead of road-intensive suburban developments cuts down on the need to drive, thus further reducing the carbon footprint.

CONTACTS: Seaside, www.seasidefl.com; Smart Communities Network, www.smartcommunities.ncat.org; NewUrbanism.org, www.newurbanism.org.

Dear EarthTalk: How safe are the fire retardants that are used to quell forest fires across the American West? -- Barbara, Minneapolis, MN

So-called long-term fire retardants—those usually dropped from airplanes over forest fires—are comprised of water mixed with a slurry of chemicals, thickeners and corrosion inhibitors designed to prevent plants on the ground from igniting, keep the ingredients from separating and dispersing during targeted drops, and ensure that the harsh chemicals on board the plane don’t endanger the flight’s safety.

Firefighters sometimes add iron oxide to make the fire retardant turn red when applied so they can see where they have already covered. Ammonium phosphate and ammonium sulfate, known for their use as agricultural fertilizers, are also often added to provide nutrients to help the forest regenerate after a burn.

In recent years, where global warming and droughts have exacerbated forest fires across the American West, federal and state firefighting agencies have upped their cumulative annual use of long-term fire retardants to some 20+ million gallons a year spread across tens of thousands of individual fly-overs.

While such chemicals have been valuable in minimizing the damage of forest fires, their use comes with a price. The nitrogen in ammonium phosphate and ammonium sulfate can wreak terrible havoc on aquatic ecosystems, creating algae blooms that kill fish by choking out their oxygen. A 1998 study by the U.S. Geological Survey’s Northern Prairie Wildlife Research Center, found long-term fire retardants to be “very toxic to aquatic organisms including algae, aquatic invertebrates and fish.” The study also said that fire-fighting chemicals “could cause substantial fish kills depending on the stream size and flow rate.”

These chemicals have also been shown to affect some plants’ reproductive capacities. One study found that spraying fire retardants in some cases decreased plant species diversity, as weedier species better adapted to make use of excess nitrogen in the soil tended to thrive while native species were not able to compete.

In 2000 the U.S. Forest Service issued guidelines for use of fire retardants by aerial fire fighting crews. While the focus of the document was fire control and safety, it encouraged pilots to avoid applying retardant within 300 feet of waterways or other sensitive areas. The Forest Service acknowledges the risk of using retardants, but believes that their use in moderation is a net gain; as fewer “ground troops” need to be sent in to risky situations while more property can be saved from the ravages of a fast-moving fire.

Fires are actually an essential part of forest ecology and many species of trees and plants thrive in part because of the natural occurrence of fires (sequoia trees, for example, depend upon the high temperatures of forest fires to pry open their cones so new seeds can spring forth and take root). The main reason that such catastrophic, news making fires occur in the first place is that humans have sprawled too closely to the forest edge. This has lead to forest management policies that suppress natural fires, causing large build-ups of tinder-like woody debris that eventually ignites and burns out of control.

CONTACTS: USGS Northern Prairie Wildlife Research Center, www.npwrc.usgs.gov; U.S. Forest Service Guidelines for Aerial Application of Retardants and Foams in Aquatic Environments, www.fs.fed.us/rm/fire/retardants/current/gen/appguide.htm.

Dear EarthTalk: There are so many energy drinks on the market, but they all seem very high in sugar, coloring and preservatives. Are there any natural versions that offer a healthier kick-start? -- John Hwang, Cambridge, MA

Energy drinks constitute one of the fastest growing sectors of the soft drink market across the U.S. and around the world, with some 500 new varieties introduced in recent years. But it’s true that most are far from healthy. Besides containing excessive amounts of sugar and caffeine, which alone can be dangerous to those with diabetes or heart conditions, many also feature a battery of supposedly beneficial herbal supplements (taurine, guarana and ginseng) that are not proven to increase energy and may actually sap energy, being detrimental to bodies overloaded with new and unfamiliar stimuli.

“Most of the energy drinks contain high-tech-sounding ingredients that are not controlled substances, of no value, and potentially harmful” in large amounts, says sports nutritionist Cynthia Sass. “The amount of the stimulants is not always listed on the label, and even when the information is listed, it is hard for consumers to interpret because we are not familiar with these ingredients.”

Sass recommends good old fashioned water as the best alternative to energy drinks. Re-hydrating is a great way to stay alert and to move other nutrients through the body. Other tried and true ways to increase energy include maintaining a healthy diet, regular physical activity and, of course, a good night’s sleep.

But what about those times when you really need a boost? Yerba mate tea, which is derived from yerba mate plants that naturally contain caffeine as well as other natural stimulants, is a popular choice. Perhaps part of the reason some people swear by it is that its brewed leaves contain theobromine—also found in cocoa—an alkaloid known to help elevate the mood. Boosters of the drink say it also helps strengthen the immune system, relieve allergies and aid in weight loss.

Not a straight tea drinker? Brewed yerba mate, which has an earthy flavor that some call an acquired taste, is sold commercially not just as tea but also blended in lattes, coffees and energy drinks. Guayaki (available at Safeway, Wegmans, 7-Eleven and elsewhere) is one of a handful of companies paving the way for yerba mate in the U.S. The company sells flavored versions with a hint of cane juice to sweeten it up for otherwise sugar-addicted American consumers.

Another take on healthy energy drinks comes from a handful of companies selling products with vitamins and nutrients instead of caffeine to give drinkers a kick. Zipfizz is a powder that can be mixed in with water and contains a combination of vitamins and minerals that provide the body with electrolytes, antioxidants and vitamin B-12, among other natural, immune-strengthening nutrients. Eniva Vibe, also packed with vitamins and minerals, is another popular new entry into the healthy energy drink market.

As with anything you consume, mileage may vary, so to speak, so experts advise going slow at first to make sure it agrees with you. And if all else fails, remember you can always just go take a nap.

CONTACTS: Cynthia Sass, www.cynthiasass.com; Guayaki, www.guayaki.com; Eniva Vibe, www.enivamembers.com/vibe_index.aspx; Zipfizz, www.zipfizz.com.

Dear EarthTalk: How or where can I recycle clothes that are too old or worn out for Goodwill? -- Tim Cheplick, Perrineville, NJ

Just because that old shirt you used to love is too threadbare to wear anymore doesn’t mean it has to end up in a landfill. “Consumers don’t understand that there’s a place for their old clothing even if something is missing a button or torn,” says Jana Hawley, a professor of textile and apparel management at the University of Missouri-Columbia. “Ninety-nine percent of used textiles are recyclable.”

Non-profits like Goodwill and the Salvation Army play a crucial role in keeping old clothes out of the waste stream. When they get donations of clothes that are too threadbare to re-sell in one of their shops, they send them to “rag sorters” that specialize in recycling pieces of fabric large and small. Says Hawley, these textile recyclers sell about half the clothing they get back overseas in developing countries, while unusable garments, especially cotton t-shirts, are turned into wiping and polishing clothes used by a variety of industries and sold to consumers. She adds that other textiles are shredded into fibers used to make new products, such as sound-deadening materials for the automotive industry, archival-quality paper, blankets and even plastic fencing.

Outdoor clothing and gear maker Patagonia, which plies a strong environmental mandate in key aspects of its operations (from sourcing of raw materials to managing waste to making grants to environmental nonprofits), in 2005 launched its innovative Common Threads Garment Recycling program. The program was originally begun so customers could return their worn out Capilene long undies for recycling, but has expanded to taking back Patagonia fleece and cotton t-shirts as well as Polartec fleece from other manufacturers. Consumers wanting to unload items that meet the program’s criteria can do so at any Patagonia retail store or by mailing them into the company’s Reno, Nevada service center.

Of course, do-it-yourselfers handy with needle-and-thread or sewing machines can turn their old clothes into new creations such as quilts, handbags and smaller items. The website Expert Village, which claims to have the largest online collection of “how-to” videos, offers a free series called “How to Recycle Old Clothes into New Fashions.” Short step-by-step videos in the series cover such topics as transforming old garments into works of art; sewing patches, buttons and beads onto old clothes; deconstructing a wedding dress; ironing graphics onto old garments, and much more. Another good use for threadbare clothes (as well as sheets and towels) is pet bedding, whether in your own home or donated to a local animal shelter.

According to the non-profit Institute for Local Self-Reliance, textiles make up about four percent of the weight and eight percent of the volume of all municipal solid waste in the U.S. The commercial recycling company U’SAgain—which runs private for-profit recycling services in Atlanta, Chicago, Dallas, Minneapolis, Seattle, St. Louis and elsewhere—finds that some 85 percent of the 70 pounds of textiles the average American purchases each year ends up landfilled. That means the typical U.S. city with 50,000 residents has to pay (with local tax dollars) for the handling and disposal of some 3,000 tons of textiles every year. The shame of such waste is that textiles are so easy to recycle or otherwise find new uses for.

CONTACTS: Goodwill, www.goodwill.org; Salvation Army, www.salvationarmy.org; Patagonia, www.patagonia.com; Expert Village, www.expertvillage.com; U’SAgain, www.usagain.com.

Dear EarthTalk: What are the conservation implications of all the wild colonies of escaped pet parrots that have turned up in and around some major U.S. cities? -- Mike Gifford, Kirkland, WA

At least three dozen different parrot species are now considered threatened or endangered in their quickly shrinking native tropical and sub-tropical habitats (mostly in South America). As such, the health of wild flocks in the U.S. and other developed countries around the world may well be key to preserving these birds that could otherwise go extinct.

Today wild parrot flocks thrive in urban and suburban areas of New York, New Jersey, Connecticut, Florida, Texas, Washington State and elsewhere. San Francisco and Brooklyn each host particularly large flocks, especially considering their relative lack of green space. Wild parrot flocks are also reportedly thriving in cities across much of Western Europe. Most of these parrots, of course, are not former pets themselves, but the descendents of birds that long ago may have escaped during transport from their jungle homes to pet stores generations ago.

Parrots are among the most intelligent and adaptable birds, so it is no surprise that they’ve done so well in North America and other regions, despite colder temperatures. Indeed it is not uncommon in the Northeast to see large groups of parrots perched in winter on deck railings piled with several inches of snow. The regions they inhabit, despite the cold weather, provide enough food and shelter to meet their relatively modest needs. And once the parrots were able to establish themselves in their new habitats, they got on with the business of breeding. Therefore, their offspring, though born in the city, are wild birds nonetheless, carrying on lifestyles not unlike those of their ancestors back in the jungles of South America (though their predators are different).

Conservationists are optimistic that the parrots’ successful adaptation to more northerly urban environments bodes well for their future, despite the loss of much of their ancestral rainforest habitat. According to Roelant Jonker of the non-profit City Parrots, encouraging the formation of wild flocks of urban parrots promises to be a much more effective conservation tactic than trying to raise more birds in captivity where they would not so readily pass on their genes or learn the survival, adaptation and social skills necessary to survive. To Jonker, the proof is in the pudding: Some 2,500 wild red-crowned Amazon parrots (a quarter of the world’s total) are thriving in and around California’s biggest urban areas at the same time their population numbers are plummeting back in their native rainforest habitat.

The 2006 Judy Irving documentary, The Wild Parrots of Telegraph Hill, shadows wild parrot crusader Mark Bittner and his efforts to care for a wild flock of Red-headed Conyers living in San Francisco. Bittner feeds birdseed to the Conyers and gets to know each individual bird and its idiosyncrasies. The film’s shots of parrots interacting with one another and with Bittner really drive the point home how much we have in common with the wild kingdom of animals all around us, whether we live in the city or the country.

CONTACTS: City Parrots, www.cityparrots.org; The Wild Parrots of Telegraph Hill, www.wildparrotsfilm.com.

Dear EarthTalk: What are the environmental consequences of leather? Are there any good alternatives? -- Brianna Jacobs, Somerville, MA

Leather is everywhere—from shoes and belts, to purses, wallets, jackets, furniture and car seats. Most probably assume that the leather that finds its way into our wardrobes and living spaces is a byproduct of the meat industry. But while cows are certainly the most popular animals to use for leather goods, in truth most of our leather is sourced from overseas, from countries like China and India, where a host of animals may be raw material for our bags and belts, including horses, deer, sheep and, in more exotic cases, alligators or snakes. All of which may make an animal-lover or vegetarian queasy.

But environmentalists have reason to forgo leather, too. Processing leather requires copious amounts of energy and a toxic stew of chemicals including formaldehyde, coal tar, and some cyanide containing finishes. The tanning process is just as pollutant-laced, and can leave chemicals in the water supply (as described in the best-selling book and popular movie, A Civil Action) and on the hands (and in the lungs) of developing world workers.

Tanneries are top polluters on the Environmental Protection Agency’s (EPA) “Superfund” list, which identifies the most critical industrial sites in need of environmental cleanup. Due to their toxicity, reports organicleather.com, “many old tannery sites can’t be used for agriculture, or built on, or even sold.” That website is the home of Mill Valley, California, retailer Organic Leather, which offers a return to the tanning practices of old—using animals that are organically fed and humanely raised and a tanning process that uses plant tannins, vegetable tannins or smoke to cure the leather with zero toxicity in the process.

But with the wealth of fashionable faux leather alternatives, there’s no need to ever wear animal skins. So-called “cruelty-free” fashions have advanced in leaps and bounds, with variations on every style of handbag, wallet, belt and boot. Online “vegan boutique”Alternative Outfitters even has a version of the ubiquitous Ugg boot made with microsuede “shearling” on the outside and synthetic wool inside, while Iowa-based Heartland Products sells western-style non-leather boots and non-leather Birkenstock sandals. Science has come up with plenty of comfortable, durable alternatives to materials made with animal products. These include vegan microfiber, which claims to match leather in strength and durability, and Pleather, Durabuck and NuSuede.

Products made with these synthetic materials tend to be less expensive than their leather counterparts and are being produced by major manufacturers like Nike, whose Durabuck athletic and hiking shoes “will stretch around the foot with the same ‘give’ as leather... and are machine washable,” according to company sources. And you won’t need to adjust your style, either. Vegetarianshoesandbags.com offers everything from purple faux snakeskin peep-toe pumps for hitting the clubs to hemp sneakers with recycled outsoles that look skate park-ready, to distinctive Pleather bags and versatile woven belts.

CONTACTS: Alternative Outfitters, www.alternativeoutfitters.com; Heartland Products, www.trvnet.net/~hrtlndp; Organic Leather, www.organicleather.com; Vegetarian Shoes and Bags, www.vegetarianshoesandbags.com.

Dear EarthTalk: My pediatrician swears by those gel hand sanitizers for lowering the risk of my family getting sick during cold and flu season. But I’ve also heard that these products can be dangerous to kids if ingested. Are there any safer alternatives that work just as well? -- Jason Blalock, Oakland, CA

A 2005 study by the Children’s Hospital in Boston compared illness rates across a study group of 292 families—half of them got hand sanitizers while the other half were given literature advising them of the benefits of frequent hand washing. The findings revealed that those families who used hand sanitizers experienced a 59 percent reduction in gastrointestinal illnesses and that the increased use of sanitizers correlated to a decreased spread of contagions in general.

Another study conducted at Colorado State University yielded similar conclusions, that alcohol-based hand sanitizers were as much as twice as effective as either regular soap or antibacterial soap at reducing germs on human hands. A Purdue University study, however, concluded that while alcohol-based hand sanitizers may kill more germs than plain or triclosan-based soaps, they do not prevent more infections that make people sick. Instead they may kill the human body’s own beneficial bacteria by stripping the skin of its outer layer of oil.

The down side of the gel/alcohol products is their danger as poison, especially for young children who may ingest the gel by licking it off their hands or eating it directly out of dispensers. Purell and Germ-X, two of the leading brands, each contain 62 percent ethyl alcohol. While this alcohol is what gives the products their germ-busting power, it also puts kids at risk of alcohol poisoning. A few squirts of the hand sanitizer—which is equivalent to124 proof booze—is enough to make a kid’s blood alcohol level .10, which is the equivalent of being legally drunk in most states.

So what’s a concerned parent to do? Unfortunately, the so-called greener alternatives out there aren’t safe to swallow either. EO Hand Sanitizer, for example, though it uses organic lavender oil also contains alcohol to sanitize the skin surface, and would also be considered poison if a large enough amount was ingested. Similarly greener (but still not safe to eat) products are available from Avant and All Terrain.

For now, soap and warm water—and constant nagging of your kids to wash their hands—may be the safest way to sanitize. Also, make sure that any hand sanitizer dispensers you may still use are kept out of the reach of little hands.

But who knows how we’ll be sanitizing our hands in the future. Researchers at Arizona State University have found that certain types of natural clays pulled right from the ground are highly effective at killing bacteria. One type of green clay has been shown to do a number on E. coli, salmonella, staph and other bacteria known to make people sick. But the research is still in its infancy, so don’t expect to see moms pulling jars of clay out of their purses anytime soon.

CONTACTS: EO Products, www.eoproducts.com; OrganicBeautySource.com, www.organicbeautysource.com; MotherNature.com, www.mothernature.com.

Dear EarthTalk: I notice occasional solar panels on roadsides, powering individual streetlamps or signs. Is any research being done to expand on this idea and implant solar collectors in roads, parking lots or sidewalks to generate power in a similar but bigger way? -- Emily Eidenier, via e-mail

The concept of using road surfaces to generate clean solar power is actually already moving beyond the idea stage. Roads absorb heat from the sun every day and are usually free of sightline obstructions that could otherwise block the transmission of light rays. And if the roads built for cars and driving are partly to blame for global warming, why not make them part of the solution too?

Idaho-based company Solar Roadways is one of the trailblazers. Electrical engineer Scott Brusaw was inspired to start the company when he heard Caltech solar energy expert Nate Lewis suggest that covering just 1.7 percent of continental U.S. land surface with photovoltaic solar collectors could produce enough power to meet the nation’s total energy demand.

Brusaw put two and two together when he realized that the interstate highway system already covers about that much of the nation’s land surface, so he got to work designing a system that combines a durable and translucent glass road surface with photovoltaic solar collectors that could be wired directly into the electricity grid. Brusaw’s innovative design would also heat the roads in winter, thus providing a important safety benefit.

With improvements in the efficiency of solar collectors in recent years, Brusaw believes his system, if implemented from coast-to-coast in place of the tarmac on existing highways, could produce enough energy to meet the entire world’s electricity needs.

But skeptics wonder whether such an expensive high-tech road surface can stand up to the rigors of everyday use—from overloaded 18-wheelers putting extra stress on the highway to oil spills seeping into expensive electronic circuitry—without having to be replaced or repaired often. Brusaw acknowledges that his system still needs fine-tuning, but in the meantime is developing a working prototype along a 45-mile stretch of road between the Idaho cities of Coeur D’Alene and Sandpoint.

Europeans are also pioneering ways to use the sun’s rays to work as they beat down on roadways. The British firm Astucia has developed a road stud that contains small solar panels and emits LED light to illuminate dark roadways. On the 120 U.K. roads where the new studs have been installed, night-time accidents are down some 70 percent.

And the Dutch firm Ooms Avenhorn Holding BV has developed a way to siphon solar heat from asphalt road surfaces and use it to de-ice roads and help power nearby buildings. A latticework of pipes under the road surface allows water to heat up during warm weather. The water is then pumped deep under ground where it maintains its higher temperatures and can be retrieved months later to keep road surfaces ice-free during winter months. Apartment buildings, industrial parks and an air force base have benefited from the innovation, and the firm is working on exporting its system to other countries in the coming years.

CONTACTS: Solar Roadways, www.solarroadways.com; Astucia, www.astucia.co.uk; Ooms Avenhorn Holding BV, www.ooms.nl/english.

Dear EarthTalk: I just read an article that said air fresheners contain chemicals that can cause health problems when inhaled. Are scented candles any better? -- Leanne Chacksfield, Cincinnati, OH

Like most air fresheners, many scented candles contain and release phthalates, potentially harmful chemicals that have been linked to the disruption of hormonal systems and other health problems in people exposed to them. Burning candles can also emit small amounts of acetaldehyde, formaldehyde and naphthalene, organic chemicals that are also potentially harmful and that can leave nasty black soot deposits on floors and other surfaces.

According to Pamela Lundquist of the nonprofit Children’s Health Environmental Coalition (CHEC), this black soot deposit “is primarily made up of elemental carbon, but may also contain phthalates and volatile organic compounds like benzene and toluene, which can cause cancer and neurological damage.”

Children can easily ingest these chemicals if their hands have been wandering and end up in their mouths. The chemicals can lodge deep in the lungs, disrupting the lower respiratory tract, exacerbating existing problems like asthma, and potentially causing other longer term breathing problems.

Despite laws against it, many candlewicks still contain lead, long linked to impaired learning and brain damage in children. Lead dispersed from burning candles can be breathed in and also constitute part of the dreaded black soot deposit. Candles with lead-containing wicks are on the U.S. Consumer Product Safety Commission ban/recall list now (thanks to efforts by nonprofits like U.S. Public Interest Research Group (PIRG), but many are still out there on store shelves. Consumers can avoid them by sticking to candles with soft cotton wicks, not stiff, metal ones.

Eco-conscious candle burners should also avoid paraffin-based candles, which are made from waxes derived in the process of refining crude oil and literally consist of fossil-fuel generating hydrocarbons. Unfortunately, the vast majority of commercially available candles are made from paraffin, though many alternatives are now available.

Soy-based candles are a popular choice, as they are made from plant waste and emit less soot than the paraffin variety. Beeswax candles are another nice alternative, as well, especially if you can pick them up at a local farmers’ market. For scented or aromatherapy candles, look for varieties that use only pure plant essential oils instead of synthetic chemicals with unintelligible names. Some leader makers of Earth- and people-friendly candles include Blue Corn Naturals, Honeyflow Farm, Vermont Soy Candles and Aveda.

CONTACTS: Children’s Health Environmental Coalition (CHEC), www.checnet.org; Blue Corn Naturals, www.bluecornnaturals.com; Honeyflow Farm, www.honeyflowfarm.com; Vermont Soy Candles, www.vermontsoycandles.com; Aveda, www.aveda.com.

Dear EarthTalk: As an online gamer, I spend a lot of time in front of my computer. What’s the environmental impact? And are “greener” PCs available? -- Bob Grant, Burlington, VT

Online gamers and other heavy computer users are definitely leaving an environmental mark. Depending on when it was made and how it was designed, a standard desktop PC can use anywhere from 60-300 watts when in use, while an inefficient gaming PC with powerful graphics card, multiple hard drives and optical drives, flash memory reader and a 30-inch LCD might consume as much as 750 watts, or about as much as a typical refrigerator. Until July of 2007, government Energy Star requirements only measured a computer’s energy use while in standby mode, which allowed the majority of brands to carry the label.

New stricter efficiency requirements have brought greener models. You’ll find the largest selection from companies like Dell and Hewlett Packard. Many businesses use the Electronic Products Environmental Assessment Tool (EPEAT) to assist in the purchase of greener computing systems, and the evaluations can be useful to consumers, too. EPEAT evaluates and rates computing equipment on 28 efficiency and sustainability criteria, awarding them bronze, silver or gold for overall performance.

Technology company VIA is well regarded as an industry leader in low-wattage processors (central processing units or CPUs), with some barely sipping only a dozen or so watts from the power supply. Some typical VIA designs can outperform competitors using only 23 watts, or less than half the power called for by Energy Star specifications. Of course graphics cards used by PC gamers are serious energy hogs. Your top-end ATI or nVidia card will render great graphics, but use 300 watts or more. Newer cards are better, but much depends on their use. The best advice is to buy only the graphics power you need.

One of the easiest ways to save on computer power is to use technology that automatically rests when you do, and to shut your computer down when you’re not using it. Windows XP allows users to configure power management settings, and Vista Ultimate lets you configure power-saving options in even more ways. Vista can actually throttle its power consumption for some tasks and power down at other times. If you’re just typing a Microsoft Word document, performance will back down, whereas if you are editing video in a powerful program like Adobe Premier Pro, Vista will use all the processing power available.

Bear in mind that screen savers are not energy savers. In fact, power-down features may not work if you have a screen saver activated. Happily, LCD color monitors do not need screen savers. In terms of shutting down, while PCs use a small amount of energy when they start up, it’s considerably less than the energy used when they are on for long periods of time. Consider turning off the monitor if you aren’t going to use your PC for more than 20 minutes, and both the CPU and monitor if you’re not going to use your PC for more than two hours.

If you’re concerned about the “wear and tear” of turning PCs on and off, don’t be. Most PCs reach the end of their “useful” life due to advances in technology long before the effects of being switched on and off multiple times can have a negative impact on their service life.

CONTACTS: Energy Star, www.energystar.gov; EPEAT, http://epeat.net; Recycling an old monitor, www.epa.gov/epaoswer/hazwaste/recycle/ecycling/donate.htm; VIA, www.via.com.

Dear EarthTalk: Vegetarians and vegans are so self-righteous about not eating meat and how meat eating is so bad for the environment. How true are these claims? -- Frank Doolittle, Sudbury, MA

There has never been a better time to go vegetarian. Mounting evidence suggests that meat-based diets are not only unhealthy, but that just about every aspect of meat production—from grazing-related loss of cropland, to the inefficiencies of feeding vast quantities of water and grain to cattle, to pollution from “factory farms”—is an environmental disaster with wide and sometimes catastrophic consequences.

There are 20 billion head of livestock on Earth, more than triple the number of people. According to the Worldwatch Institute, global livestock population has increased 60 percent since 1961, and the number of fowl being raised for food has nearly quadrupled in the same time period, from 4.2 billion to 15.7 billion.

The 4.8 pounds of grain fed to cattle to make one pound of beef represents a colossal waste of resources in a world teeming with hungry and malnourished people. According to Vegfam, a 10-acre farm can support 60 people growing soy, 24 people growing wheat, 10 people growing corn—but only two raising cattle.

Food First’s Frances Moore Lappé says to imagine sitting down to an eight-ounce steak. “Then imagine the room filled with 45 to 50 people with empty bowls... For the feed cost of your steak, each of their bowls could be filled with a full cup of cooked cereal grains.” Harvard nutritionist Jean Mayer says that reducing U.S. meat production 10 percent would free grain to feed 60 million people.

U.S. animal farms generate billion of tons of animal waste every year, which the Environmental Protection Agency says pollute our waterways more than all other industrial sources combined. The infamous 1989 Exxon Valdez oil spill dumped 11 million gallons of oil into Prudoe Bay, but the relatively unknown 1995 New River hog waste spill in North Carolina poured 25 million gallons of excrement into the water, killing 14 million fish and closing 364,000 acres of shell fishing beds. Hog waste spills have caused the rapid spread of Pfiesteria piscicida, which has killed a billion fish in North Carolina alone.

Other than polluting water, beef production alone uses more water than is used in growing our entire fruit and vegetable crop. And over a third of all raw materials and fossil fuels consumed in the U.S. are used in animal production. Meat also increases our carbon footprints. According to the United Nations’ Food and Agriculture Organization, livestock around the world contribute more greenhouse gases (mostly methane) to the atmosphere—18 percent of our total output—than emissions from all the world’s cars and trucks.

“There is no question that the choice to become a vegetarian or lower meat consumption is one of the most positive lifestyle changes a person could make in terms of reducing one’s personal impact on the environment,” says Christopher Flavin of the Worldwatch Institute. “The resource requirements and environmental degradation associated with a meat-based diet are very substantial.”

CONTACTS: Food First, www.foodfirst.org; UN Food and Agriculture Organization, www.fao.org; Worldwatch Institute, www.worldwatch.org.

Dear EarthTalk: Everybody says stop using plastic bags, but what about all the plastic, cellophane, cardboard and other materials used for packaging the food itself? What can we do to reduce how much of this unnecessary stuff comes wrapped around our food? -- Sunil Sreedharan, Mumbai, India

Yes, food packaging is a big problem in North America as well as elsewhere around the world, with landfills filling up and recyclers facing a glut of materials to process. It’s hard to say just how much of the 130 million tons of paper, plastic and metals that get tossed or sorted for recycling in major U.S. cities is from food packaging, but the percentage is no doubt sizable. The main problem is in the psychology of marketing: Manufacturers know that products in big flashy-looking packages attract more buyers.

A 1994 European Union directive requires companies operating in its 27 member nations to take back and recycle (or otherwise deal with, taking the burden off of local communities) at least 60 percent of their packaging waste, including that used for food items. But no such “producer pays” laws, which provide incentive for manufacturers to cut back on waste to begin with, exist in the United States or Canada. As such, it falls to consumers to patronize stores and manufacturers that minimize packaging.

One way to take a bite out of packaging is to buy as much in bulk as your family can keep up with. It may take longer to get through that gigantic box of cereal you got at Costco, but think of all the cardboard and plastic your bulk purchase saved over buying several small boxes. Similarly, instead of sending the kids off to school every day with a new juice box in the lunch bag, how about a safe metal or plastic reusable, washable container that you can refill each morning from the gallon jug you keep in the fridge?

Another way to forego packaging is to reduce time spent in large supermarkets, where wasteful product packaging rules. Most natural foods stores have large bulk-buying sections so you can haul away in large paper or plastic bags the equivalent of many containers of beans, pastas, rice or other staples. Frequenting local farmers’ markets—armed with your reusable shopping tote, of course—is another way to keep food packaging out of your home. The website Local Harvest offers a free searchable database of farms across the U.S. that run Community Supported Agriculture (CSA) programs and participate in farmers’ markets.

It’s worth noting that we tend to toss way too much food packaging where a quick rinse would make the same cans, jars and jugs useful storage containers or quality recycling fodder. Soup cans, for example, can easily be recycled into new steel and are collected universally by municipal recycling programs. And while you’re buying soup, opt for the family size cans and save leftovers instead of buying single-serving containers. Even when packaging material is recyclable, there’s no reason to waste it, as even recycling uses resources and costs money.

Beyond shopping and sorting more responsibly, individuals also have the power of their voices to pressure food makers to cut back on packaging. You can also try to persuade your elected officials to look into the feasibility of enacting “producer pays” laws in your community, city or state. And you can talk to co-workers, friends, relatives and others about the importance of buying in bulk and reducing waste.

CONTACTS: European Union Packaging and Packaging Waste Directive, http://europa.eu/scadplus/leg/en/lvb/l21207.htm; Local Harvest, www.localharvest.org.

Dear EarthTalk: As I understand it, coal that is used to fuel power plants and other industrial activity is a key culprit in pollution and climate change. So what is “clean coal” and is it really? -- Matthew Oliver, Minneapolis, MN

The term “clean coal” describes various processes that remove pollutants from coal, our cheapest, most abundant—and dirtiest—energy source. By reducing coal’s environmental footprint through technological wizardry, the coal mining industry and the Bush administration hope to keep coal, which currently produces more than half of all U.S. electricity, a big part of our energy picture for many years to come.

Clean coal proponents also want to liquefy coal to turn it into a form of automotive fuel that, according to the industry-sponsored Coal-to-Liquids Coalition, costs less and burns cleaner in some ways than the traditional diesel fuel it could replace. Several members of Congress from coal states are keen on having the government subsidize the production of so-called liquid coal—which can be used anywhere diesel fuel currently goes—as a “homegrown” alternative to foreign oil. Industry analysts say there is enough coal in America to last hundreds of years, saving us untold expense and trouble obtaining regular petroleum from unfriendly foreign governments.

But major environmental groups, from the Sierra Club to the Natural Resources Defense Council, say that “clean coal” is anything but. The process involves heating coal to 1,000 degrees Fahrenheit and mixing it with water to produce a gas, then converting the gas into diesel fuel. Although the Coal-to-Liquids Coalition says that carbon dioxide emissions from the entire production cycle of liquid coal are “equal to, or slightly below, those of conventional petroleum-derived fuels,” its claims are based on a single federal study, now six years old, that environmental leaders disagree with profoundly.

Jim Presswood, federal energy advocate of the Natural Resources Defense Council says, “Liquid CO2 emissions are twice as much as emissions from conventional petroleum-derived fuels.” He says that even if CO2 emissions were captured as part of the process, at best liquid coal would be 12 percent worse than the gasoline equivalent. As some environmentalists have put it, liquid coal can turn any hybrid Prius into a Hummer.

The Washington Post editorialized, “To wean the U.S. off of just one million barrels of the 21 million barrels of crude oil consumed daily, an estimated 120 million tons of coal would need to be mined each year. The process requires vast amounts of water, particularly a concern in the parched West. And the price of a plant is estimated at $4 billion.” Also, in recent years, particularly in Appalachia, mining companies have gone from simple excavation to blasting off the tops of mountains in an ecologically devastating process known as “mountain top removal.”

For their part, greens acknowledge the importance of cleaning up coal and other dirty energy sources, but would rather see more funding devoted to researching, developing and implementing alternative and renewable energy sources that don’t come with so much environmental baggage.

CONTACTS: Coal-to-Liquids Coalition, www.futurecoalfuels.org; Sierra Club’s “Stopping the Coal Rush,” www.sierraclub.org/environmentallaw/coal.

Dear EarthTalk: What’s a “land trust” and how does it help the environment? -- Sam Stout, Darien, CT

A land trust is an organization that works with landowners to conserve their land, either by buying it from them or obtaining it as a donation. Legal agreements between the trust, the landowner and the local government are then created in order to permanently limit development of the land. Land trusts are usually nonprofit, and their purpose is to provide long-term stewardship of not just land, but sometimes areas of historical or archeological significance.

The need for land trusts arose out of public concern for the loss of open space, wildlife habitat and scenic beauty in the face of rampant development on private land during the latter half of the 20th century. More than 1,600 land trusts have since sprung up in a variety of communities across the U.S. Together they have protected some 37 million acres of land, according to the Land Trust Alliance, a Washington, DC-based umbrella group formed in 1981 to help land trusts share information and work more effectively.

When a land trust acquires land, it may retain ownership in perpetuity in order to protect the parcel from development. When landowners donate parcels to a land trust outright, they can take advantage of state and federal income tax deductions—similar to any tax-deductible, non-profit donation—while saving considerable money on property and estate taxes moving forward.

Whether a land trust buys a parcel or gets it donated, it can either hold onto the property or, depending on the arrangement with the former owner, sell it to a third party—often a local or state government that commits to turning it into a protected area. Land trusts also sell land to private buyers, usually with strict restrictions on future development. The benefit to keeping the land under private ownership is that it can then stay on local property tax rolls and thus continue to provide revenue for the local government.

Another way land trusts work is through “conservation easements,” whereby individuals can protect their land but still retain ownership and the option of selling or passing it along to heirs. Future owners of the land are also bound by the easement’s terms, which restrict development and use and are often monitored by a land trust. Conservation easements usually lower the financial value of their land (by limiting development potential), but landowners benefit because their property taxes go down accordingly. Likewise, if and when heirs inherit the land, the conservation easement lessens their estate tax burden.

Every conservation easement is different, but most include provisions limiting or forbidding construction or resource extraction. Often they protect especially sensitive lands such as wetlands. Some easements allow specific parcels to be used for agriculture, ranching or logging. Many allow hiking, camping, bird watching or even hunting (though some specifically ban hunting and are created for that purpose).

Another nonprofit group, the American Land Conservancy (ALC), functions like a national land trust working nationwide to ensure that large or exceptional pieces of property stay out of the hands of developers. Some of ALC’s work has led to the creation or expansion of national parks in Colorado, Hawaii and elsewhere.

CONTACTS: Land Trust Alliance, www.lta.org; American Land Conservancy, www.alcnet.org.

Dear EarthTalk: Is the pressure-treated wood used for decks, picnic tables and backyard play structures harmful to human health? -- Christy Silver, Cleveland, OH

Pressure-treated wood contains the preservative chromated copper arsenate (CCA), an arsenic derivative that is used to protect the wood and prolong its life. Also used commercially as a pesticide, CCA is regarded by many homeowners and construction professionals as a godsend for preserving outdoor wood structures against harsh weather and termites. But it is also on environmentalists’ watch lists as a potential health hazard due to its arsenic content.

According to the US Environmental Protection Agency (EPA), arsenic, although a naturally occurring element found in the Earth’s crust, is poisonous. Prolonged exposure can cause vomiting, diarrhea and skin abnormalities. The EPA also considers arsenic to be a human carcinogen, with long-term exposure increasing the risk of skin cancer and tumors of the bladder, kidney, liver and lung.

Recent studies have shown that rainwater can release arsenic-laden CCA from the treated wood, potentially contaminating any soil or groundwater below. Also, especially after a heavy rain, a fine coating of CCA residue can build up directly on the wood’s surface, which in turn can be picked up on hands and clothing, potentially exposing family members to small but persistent doses of arsenic.

But while the EPA may classify arsenic itself as a toxin, it does not believe that periodic contact with pressure-treated wood poses any “unreasonable” risk. The agency has, however, issued new safeguards for protecting workers who come into contact with CCA on a daily basis. Even the nation’s largest producer of pressure treated wood, Arch Wood Protection Inc., advises taking precautions when working with, using and cleaning up its products, acknowledging that “exposure to CCA may present certain hazards.”

If you already have pressure treated wood around your home, applying an oil-based stain once every couple of years will help keep the CCA from seeping out. Additionally, you should keep children and pets out of under-deck areas where arsenic may be present. Also, don’t grow edible plants near any pressure treated wood structures, and always follow safe handling guidelines (including the use of gloves and dust masks) when using it in building projects.

For those who may be starting from scratch, there are several safer alternatives to pressure treated wood. According to the Berkeley, California based Green Resource Center, yellow cypress, yew, tamarack, hemlock, white cedar and redwood are naturally rot-resistant, as are plastic and wood-plastic composite building materials. Meanwhile, wood boards that are treated with alternative techniques that don’t use CCA are free of the arsenic problem. Alkaline Copper Quartenary, sold under the trade name NatureWood, is one safer option, as is Copper Azole, which is sold under the trade name Natural Select.

CONTACTS: EPA Arsenic Toxicity Assessment, www.epa.gov/ttn/atw/hlthef/arsenic.html; Green Resource Center, (510) 845-0472, www.greenresourcecenter.org; NatureWood, (800) 241-0240, www.osmose.com/wood/usa/preserved/naturewood/product/; Natural Select, (866) 789-4567, www.naturalselect.com.

Why have shark attacks been on the rise in recent years? -- J. Tibbetts, Boston, MA

Despite a slight downturn during the last few years as a result of hurricanes keeping people out of the water, the number of shark attacks on humans has indeed risen steadily over the last century. In fact, the nearly 500 shark attacks recorded around the world in the 1990s was double that which occurred in the previous decade, and that trend seems to be continuing apace into the new millennium.

The largest increase in shark attacks has been along the southeastern seaboard of the United States. The summer of 2001 witnessed sharks moving in to shallower waters and striking people near the shoreline. In just three weeks there were 20 attacks and two deaths--often in water no more than three feet deep.

The largest increase in shark attacks has been along the southeastern seaboard of the United States. The summer of 2001 witnessed sharks moving in to shallower waters and striking people near the shoreline. In just three weeks there were 20 attacks and two deaths--often in water no more than three feet deep.

Unproven theories abound regarding this phenomenon. Some experts postulate that the human-caused decline in ocean fish is causing sharks to venture closer to shore in search of food. Others believe that sharks’ territories are shifting due to changes in ocean temperatures resulting from global warming.

Whether or not these theories have merit, no one doubts that humans are venturing further and further out to sea to swim, surf, snorkel and dive, increasing the chances of run-ins with sharks. Surfers are especially at risk because their shiny black wetsuits look like tasty seals to sharks. Also, surfers spend lots of time waiting for waves in the “splash zone” just offshore, where sharks tend to congregate to look for prey.

“An ever growing number of people spend their vacation at the oceanside, so that both the probability of encountering a shark and the respective danger of an accident also increases,” says Dr. Alexander Godknecht, president of the Shark Foundation. Godknecht believes the 100 or so shark attacks last year to be a very small number and that mainstream media hype makes them appear to happen more often than they really do.

George Burgess, director of the International Shark Attack File (ISAF) at the Florida Museum of Natural History, agrees, arguing that the average North American is about 15,000 times more likely to be killed in a car accident than in a shark attack. “Bees, wasps and snakes cause far more fatalities a year,” he adds. “And the annual risk of death from lightning is 30 times greater than that from a shark attack.”

Burgess points out that, despite the increase in shark attacks, shark populations are actually in decline globally, mostly due to human overfishing which has depleted their sustenance. Along the Atlantic coast of the U.S. some shark species have declined as much as 70 percent over the last 20 years. “The number of shark attacks is rising every year while the shark population is dwindling--it’s not rocket science to see that something is provoking them. We’re swamping the near-shore environment,” Burgess concludes.

CONTACTS: Shark Foundation, www.shark.ch; International Shark Attack File, www.flmnh.ufl.edu/fish/Sharks/ISAF/ISAF.htm.

Dear EarthTalk: Which types of household products are most likely to cause chemical sensitivities? -- John Morgan, Somerville, MA

Household products trigger chemical sensitivities in hundreds of thousands of Americans every year, yet few people make the connection between their skin rash or sneezing and the bottles and cans stored under their kitchen sink or in the broom closet.

Common reactions to everyday household cleansers and other substances include migraine headaches, asthma and sinusitis, but more serious cardiovascular, neurological and autoimmune diseases may also result from prolonged use or lack of adequate ventilation in areas where these chemicals are being applied. “Early warning signs are burning and irritation of the sinuses, nose or throat--usually not with a fever--and itching or sneezing,” says Dr. Grace Ziem, a public health physician specializing in chemical injuries.

Prevention is the key. And removing toxic compounds from your home is the strategy. You can begin under the kitchen sink by replacing traditional choices with “products your grandmother bought,” says Suzanne Olson of the Environmental Health Network. “Borax, vinegar and baking soda will clean most items around the house.” Olson uses vegetable oil to polish furniture and shuns any items with a fragrance.

“If any ingredients end in ‘ethylene’ or ‘ethane,’ it’s not a healthy product,” says Cynthia Wilson of the Chemical Injury Information Network. She recommends using scent-free and dye-free laundry products, and oxygen-based whitening additives in place of toxic bleach. Two companies that supply non-toxic laundry products as well as other green-friendly household cleaners include Seventh Generation and Earth Friendly Products. You can shop both online or in natural foods markets and some supermarkets.

Synthetic home furnishings can also trigger sensitivities. Foam, particleboard and veneers can all aggravate a variety of symptoms. And sweet dreams may elude you if you have chemical sensitivities to items in your bedroom. Most mattresses are made from artificial materials, and some beds have chemical mold inhibitors while almost all have fire retardant. In order to eliminate chemical sensitivities from ruining your sleep, choose a mattress manufactured from organically grown cotton. Two good sources include Lifekind Products and Heart of Vermont; both offer secure, online ordering.

If you think some household chemicals might be bothering you, Dr. Ziem suggests keeping a log to help pinpoint the offenders. The best way to find out whether any chronic ailments you may have are caused or aggravated by household products is to take a simple inventory of the home and its contents, and replace synthetic products with natural ones wherever possible. By ridding the home of some of these culprits, you and your family are bound to breathe easier.

CONTACTS: Environmental Health Network, http://users.lmi.net/wilworks/; Chemical Injury Information Network, www.ciin.org. Seventh Generation, (800) 456-1191, www.seventhgeneration.com; Earth Friendly Products, (800) 335-3267, www.ecos.com; Lifekind, www.lifekind.com, (800) 284-4983; Heart of Vermont, (800) 639-4123, www.heartofvermont.com.

How can I recycle my outdated computer equipment? -- Kenneth Rapp, Toms River, NJ

Computers are infamous for their rapid obsolescence. These days you can expect a new computer to serve you for three to five years at best before “must have” features become available only in newer models. Many companies have “computer graveyards”--rooms filled to the ceiling with outdated computers, printers, monitors, cables and other accessories that are no longer in operation and seemingly have nowhere to go but the junk heap.

It’s no surprise then that more than 10 million computers end up in American landfills every year. But old computer equipment languishing in landfills poses myriad environmental hazards, as many contain toxic compounds that can seep into surrounding land and groundwater. According to USA Today, the average PC contains “five pounds of lead (to protect the user from radiation) in the cathode ray tube monitor alone. Circuit boards typically contain cadmium, mercury and chromium while the whole package is housed in brominated, flame-retardant plastic.” The National Safety Council reports that by the end of 2005, 350 million computers will have reached obsolescence, with at least 55 million of them expected to end up in landfills unless recycling increases.

According to Nikki and David Goldbeck’s book, Choose to Reuse, many computers can be saved and don't need to end up in landfills. The first thing to check is if your old computer can be upgraded; often the substitution of a simple memory chip can make a slowpoke speed up considerably. And RAM memory--?provided there are sufficient expansion slots--is getting cheaper all the time.

If an upgrade won't work, there are alternatives to landfills. Goodwill and The Salvation Army will take working older equipment and re-sell it. “Free Computer” ads can be posted at schools and workplaces. And brokers like American Computer Exchange will take your hardware for trade on a newer model.

Meanwhile, many worthy non-profit groups will make good use of computer equipment outdated for your needs. The National Cristina Foundation places used technology with non-profit organizations and public agencies that serve the disabled and economically disadvantaged. For a more do-it-yourself approach, The Global Crisis Solution Center provides a free online resource hooking up equipment donors with needy non-profits.

Europe is leading the way in keeping computers out of landfills, with all computer manufacturers required to have recycling programs in place. In the U.S., several makers will now recycle or exchange computers, often for a marginal fee. IBM, Dell Computer and Hewlett-Packard have all started such programs.

CONTACTS: American Computer Exchange, www.amcoex.com; National Cristina Foundation, www.cristina.org; Global Crisis Solution Center, www.globalcrisis.info/computerrecycle.html; IBM Product Recycling Program, www.ibm.com/ibm/environment/products/prp.shtml; Dell Recycling, www1.us.dell.com/content/topics/segtopic.aspx/dell_recycling; Hewlett-Packard Product Recycling, www.hp.com/hpinfo/globalcitizenship/environment/recycle/.

Dear EarthTalk: What impact does mining for diamonds and other gems have on the environment? -- Tiffany Schultz, Dayton, OH

Gem mining around the world can indeed be very destructive to the surrounding environment, leading to many problems such as soil erosion and sedimentation, water pollution and depletion, poisoning of wildlife and vegetation, flooding--even landslides. The contents of “mine tailings”--rock and other waste materials separated and left behind in the mining process--can wreak havoc on nearby agricultural lands, and pose myriad human health problems.

In the United States, mining companies are legally obligated to conduct environmental impact studies of proposed sites and then, if approved by regulators, follow the letter of the law regarding the protection of wildlife, air and water, and the proper disposal of hazardous waste. Furthermore, many U.S. states have “reclamation” laws on the books calling for the safeguarding of surface and groundwater around mining operations, and cleanup and re-vegetation after the fact to restore mining areas to their original condition.

But mines outside U.S. borders are not subject to the same rules as they are here in the U.S., even if run by American companies. Large-scale demand means large-scale mining operations, and that often means massive amounts of sedimentation and tailings falling into water systems around the world. The mercury and cyanide used to separate gold and copper from rock also make their way into our air and water.

With no country-of-origin labeling laws or system in the jewelry and gem trade, consumers can never be sure if their bracelets, rings and necklaces come from responsible sources or from companies whose mining operations are polluting, destroying wildlife habitat, exploiting poor or indigenous people (and their resources)--or funding a civil war, as does the diamond trade in Angola and Sierra Leone.

According to Friends of the Earth, mining giant Freeport-McMoRan Copper and Gold in 1996 was dumping 110,000 tons of mine tailings into the local river system on a daily basis. Plans to expand Freeport’s mining activities in Indonesia, according to the company’s own environmental auditors, could “increase its dumping of untreated tailings to 285,000 tons daily,” presenting serious health challenges for local residents who have little in the way of power or resources to halt such activity.

Obtaining jewels, however, does not have to be a destructive proposition. People have been finding valuable gems and minerals for centuries by panning for them themselves in rivers and streams. There are even “theme parks” scattered across U.S., such as Gold City, in Franklin, North Carolina, that let you “mine your own gemstones.” And companies such as Junk to Jewels and Snooty Jewelry sell jewelry made from recycled materials, handmade beads and glass. Another company, Global Marketplace, sells a wide range of jewelry made by artists in developing countries such as Nepal, Mexico and Chile, thus helping producers in these nations increase their standard of living above the poverty line.

CONTACTS: Friends of the Earth, (877) 843-8687, www.foe.org; Gold City, (800) 713-7767, www.goldcityamusement.com; Junk to Jewels, www.junktojewels.net; Snooty Jewelry, www.snootyjewelry.com; Global Marketplace, www.globalmarketplace.org.

Although salt and various salt derivatives melt ice effectively and make both walkways and roads safer, they can be damaging to the environment. After salt is applied, it washes off paved surfaces into storm drains or onto adjacent ground, and can then be carried into nearby bodies of water. According to The New York Times, this salty runoff poisons fish and wilts vegetation. It also corrodes metals, damages concrete and poses health risks to people with high blood pressure.

However, arsenic is also a by-product of industrial activity, such as coal burning, waste burning, copper smelting, and mining for gold and other metals. It is also an agricultural byproduct as it is a component of some pesticides and feed additives. U.S. smokestack and agricultural industries release thousands of pounds of arsenic into the environment each year--and as a result arsenic can show up in public water supplies in amounts that do pose health threats.

Some studies have also shown that salt applied to road surfaces increases automobile collisions with wildlife, especially white-tailed deer that are attracted to natural and artificial salt deposits in their normal course of feeding.

Despite these facts, salt remains the cheapest and most effective way to keep pavement free of ice. According to materials consultant Henry Kirchner, individuals can effectively use salt with minimum impact: “Do not use a chemical deicer to melt every bit of ice,” says Kirchner. “Use only enough to break the ice/pavement bond, then remove the remaining slush by plowing or shoveling.” All snow should be cleared away first, and the ice should be chipped off and moved away from water supplies and vegetation.

For small jobs, it may be feasible to use more potent, less environmentally toxic de-icers like magnesium chloride or calcium magnesium acetate instead of rock salt. These stronger, though more expensive, compounds can be strategically applied before a storm to block ice from forming. Sand and cat litter can be used to provide temporary traction, but these materials may dog surface water and bury plants. Although many researchers are experimenting with even more benign de-icers, including by-products of corn and cheese processing, none of these compounds is currently available to consumers.

Perhaps the larger issue is how municipalities store and use large amounts of road salt. Many of the most severe cases of environmental contamination have been caused by improper storage. When salt is stored outside uncovered, rain and snow can carry large quantities to surrounding soil and water.

As to reducing salt use, many cities and towns simply don’t de-ice in flat residential areas, except during ice storms. Some use a mix of sand and salt, instead of pure salt. Also, salt spreading equipment that is well maintained will distribute salt more accurately and, as a result, use less. Additionally, salt that is wetted before being spread sticks better to the road.

According to the trade magazine, Better Roads, a product called Verglimit, a mixture of de-icing salts and caustic soda, can be mixed with asphalt roadway during paving. Its installation doubles the cost of surfacing a road, but helps reduce the amount of salt needed for de-icing roadways and, according to the magazine, “in certain conditions can eliminate the need for salting entirely.”

CONTACTS: The Salt Institute, (703) 549-4648, www.saltinstitute.org; Better Roads, “Materials for Deicing and Anti-icing,” www.betterroads.com/articles/NewProds/Apr03bid.htm.

Dear EarthTalk: I have developed asthma from the fiberglass insulation in our home. How can I find insulation that won’t make me sick? -- Cynthia Bacon, Orlando, FL

Fiberglass, a common home insulator that grew popular after the dangers of asbestos became more widely known, is itself now associated with a range of health issues. Microscopic slivers of fiberglass can break loose during handling and be inhaled, irritating the lining of the respiratory tract and becoming lodged in lung tissue. This can cause a fibrous buildup that reduces lung capacity, or cause DNA mutations that can lead to lung cancer. In fact, cancer warnings appear on all fiberglass insulation sold in the United States.

Although wearing a respirator or dust mask can prevent inhalation of fibers during installation, all three principal U.S. manufacturers of fiberglass insulation now seal their batts in a perforated polyethylene or polypropylene sheeting so as to prevent airborne exposure. Nevertheless, for those suffering from aggravated respiratory problems, replacing fiberglass insulation with a more environmentally friendly alternative may be the best option. Luckily there are many such options available.

A favorite of environmental advocates is cellulose, which is made from recycled, shredded newspaper. In his book, The Solar House, author Dan Chiras calls cellulose “one of the most environmentally friendly insulation choices.” It is also highly efficient, readily available and economically priced, he says, and thus competes well with fiberglass.

Chiras also recommends cotton insulation, calling it “a natural product and safe from a human health standpoint,” while acknowledging that it is twice the price of fiberglass and “one of the most chemically intensive crops grown in the United States.” It contains no formaldehyde binders, however, a health and environmental plus, and usually contains a fire retardant, an important safety consideration.

Radiant barriers are another option, says the Fiberglass Information Network. Ideal for hot climates, they are made from metal foil and either kraft paper or bubble wrap. The Network also recommends insulation batts made from recycled #1 plastic, known as PET, the same material used to make some soda bottles and carpeting. Made by RTICA, based in Stony Creek, Ontario, the batts are installed just like fiberglass and make for an excellent fiberglass replacement choice.

But before ripping out that old fiberglass, it may be worth getting a professional to evaluate the integrity of your home’s ductwork. With properly sealed ducts, any stray fiberglass slivers inside your walls should not be able to get out. In the case of duct contamination, your best bet is to replace the entire system. Duct cleaning is also an option, but the U.S. Environmental Protection Agency does not recommend it. If you do decide to opt for cleaning, the National Air Duct Cleaners Association offers a list of companies that can do the work.

Critics also point to the fact that meat-based diets exacerbate world hunger. Harvard nutritionist Jean Mayer estimates that a 10 percent reduction in U.S. meat consumption would free up enough grain to feed 60 million people. Some 40 percent of the world’s grain harvest is fed to livestock, while nearly a billion people go hungry each day.

CONTACTS: Fiberglass Information Network, www.sustainableenterprises.com/fin; RTICA, (905) 643-8669, www.rtica.com, National Air Duct Cleaners Association, (202) 737-2926, www.nadca.com.

Dear EarthTalk: What is being done about arsenic contamination in drinking water? -- Erika Maxel, Cleveland, OH

Arsenic occurs naturally in our environment, and there are trace amounts of it in all living matter. In fact, arsenic is part of the Earth’s crust, and as a natural component of underground rock and soil it can work its way into our groundwater in amounts that pose little or no threat to human health.

However, arsenic is also a by-product of industrial activity, such as coal burning, waste burning, copper smelting, and mining for gold and other metals. It is also an agricultural byproduct as it is a component of some pesticides and feed additives. U.S. smokestack and agricultural industries release thousands of pounds of arsenic into the environment each year--and as a result arsenic can show up in public water supplies in amounts that do pose health threats.

According to a 1999 study by the National Academy of Sciences, excessive arsenic in drinking water can cause bladder, lung and skin cancer, and may cause kidney and liver cancer. The study also found that arsenic harms the central and peripheral nervous systems, as well as heart and blood vessels, and causes serious skin problems. It also may cause birth defects and reproductive problems.

The U.S. government regulates arsenic content in drinking water by setting a maximum contaminant level which, for many years, was 50 parts per billion. After further and more recent study, the U.S. Environmental Protection Agency (EPA) recommended in 2001 that the maximum level be lowered to just 10 parts per billion. Initially, the Bush administration rejected the recommendation, arguing that there was no scientific consensus to justify the $200 million it would cost to change the standard. But pressure from environmental and public health organizations convinced the White House to change course and adopt the stricter standard, which will take effect in 2006.

Although few if any municipal water systems in the U.S. exceed the present limit, it is estimated that many will have to install or upgrade treatment processes in order to meet the new stricter standard. Research by the Natural Resources Defense Council (NRDC) indicates that more than 34 million Americans drink tap water supplied by systems containing average levels of arsenic that pose unacceptable health risks.

Consumers can determine the arsenic levels, if any, in their drinking water by reading the Drinking Water Quality Report (also known as the Consumer Confidence Report) issued in July every year by each municipal water utility. Individuals can reduce their exposure to arsenic in drinking water by using a water filter certified by the National Sanitation Foundation (NSF). Consumers should also beware that bottled water is not necessarily any safer than tap water. According to NRDC, bottled water is often nothing more than tap water that may or may not have been filtered--so filtration is the only way to be sure that drinking water is arsenic-free.

CONTACTS: U.S. EPA Arsenic in Drinking Water page, www.epa.gov/safewater/arsenic.html; EPA Consumer Confidence Report page, www.epa.gov/safewater/ccr1.html; Natural Resources Defense Council, (212) 727-2700, www.nrdc.org; National Sanitation Foundation, (800) NSF-MARK, www.nsf.org.

Dear EarthTalk: What is the modern meat industry’s impact on the environment? -- Jeremy Smith, Bellefonte, PA

In E - The Environmental Magazine’s January/February 2002 cover story, “So You’re an Environmentalist…Why Are You Still Eating Meat?” author Jim Motavalli wrote, “Just about every aspect of meat production--from grazing-related loss of cropland and open space, to the inefficiencies of feeding vast quantities of water and grain to cattle in a hungry world, to pollution from ‘factory farms’--is an environmental disaster with wide and sometimes catastrophic consequences.”

Indeed, according to the Sierra Club, producing one pound of grain-fed beef requires about 16 pounds of wheat and--as staggering as it sounds--2,500 gallons of water. Furthermore, millions of acres of forest have been cleared worldwide to make room for the large areas of land needed for cattle grazing. In the United States, more than 260 million acres of forest have been cleared to grow crops to feed animals raised for meat, and an acre of trees disappears every eight seconds.

Tropical rainforests are also being cut to create grazing land for cattle. Fifty-five square feet of rainforest may be destroyed to produce just one quarter-pound burger. Since trees absorb carbon dioxide, the leading “greenhouse gas,” this significant loss of forest contributes to global warming as well.

Soil erosion is also mostly due to the meat industry which, according to the Worldwatch Institute, is directly responsible for 85 percent of all soil erosion in the U.S. because so much grain is needed to feed the animals. Livestock is fed more than 80 percent of the corn and 95 percent of the oats grown by American farmers. The world’s cattle alone consume a quantity of food equal to the caloric needs of 8.7 billion people--more than the entire human population on Earth.

Additionally, some believe that GE foods can be hazardous to human health when ingested. Ronnie Cummins of the Organic Consumers Association says that GE foods have been linked to many health problems, including blood disorders and food allergies. For instance, a few years ago Pioneer Hi-Bred International, in order to boost the protein content of its products, developed a soybean using a gene from a Brazil nut. Independent tests on the GE soybean revealed that people allergic to Brazil nuts could have severe allergic reactions to the modified soybeans.

A recent report prepared for the Senate Agricultural Committee concluded that animal waste is the largest contributor to pollution in 60 percent of the rivers and streams classified as “impaired” by the U.S. Environmental Protection Agency. The report states that food animals produce waste at a rate of roughly 68,000 pounds per second. Major waste pollutants that make their way into our waterways include nutrients like nitrogen and phosphorus that can cause massive fish kills, harmful bacteria and viruses, and toxic heavy metals, which are present in some commercial livestock feed.

Critics also point to the fact that meat-based diets exacerbate world hunger. Harvard nutritionist Jean Mayer estimates that a 10 percent reduction in U.S. meat consumption would free up enough grain to feed 60 million people. Some 40 percent of the world’s grain harvest is fed to livestock, while nearly a billion people go hungry each day.

While environmental groups recognize the benefits of vegetarianism as an alternative, few recommend it for everyone. Meat-loving environmentalists can look for small farms that feed livestock natural, organic diets, treat animals more humanely, and practice more sustainable land use.

CONTACTS: E Magazine, January/February 2002 issue, www.emagazine.com/view/?142; Sierra Club, (415) 977-5500, www.sierraclub.org/factoryfarms/ ; Worldwatch Institute, (202) 452-1999, www.worldwatch.org.

Dear EarthTalk: Are contact lens fluids safe for the environment and personal health? -- M. Luh, Storrs, CT

According to the Contact Lens Council, approximately 34 million Americans now wear contact lenses. Most people use various saline and disinfectant solutions for their lenses from big-name companies like Bausch & Lomb and Johnson & Johnson. These products are usually packaged in squeeze bottles that, according to Food and Drug Administration (FDA) regulations, are required to have preservatives.

But many preservatives can cause irritation and discomfort to the user. For example, thimerasol, a preservative commonly used in contact lens disinfectant solutions in the past, was found to be the culprit in severe allergies. One particularly harmful by-product of thimerasol, once it degrades or metabolizes, is ethyl mercury, which researchers now believe plays a role in the development of autism and a number of health problems.

Other preservatives like benzalkonium chloride have now replaced thimerasol in contact lens solutions. However, according to the Switzerland-based Perret Opticiens, there is still the possibility of such allergic reactions as redness, itching and discharge with the new generation of preservatives being used in conventional solutions.

A Danish study by Kolstad, Brandt and Rasmussen revealed that pregnant dry cleaning workers are twice as likely to have a miscarriage as pregnant women in other professions. And the University of California at Berkeley found that male dry cleaning workers have more sperm abnormalities and a significantly lower sperm count than men not employed by the industry.

Less toxic alternatives to perc are beginning to take hold. Comet Cleaners, which has 350 locations in 17 states and Mexico, replaced perc a decade ago with the more benign petroleum solvent, Exxon D-2000. Other cleaners have switched over to Chevron-Phillips’ EcoSolv, a similar hydrocarbon-based alternative. Meanwhile, more than 200 cleaners--including Chicago’s Greener Cleaner--employ “wet cleaning,” a non-toxic, non-polluting alternative that uses biodegradable soap and water.

There are other options. Clear Conscience now makes a line of contact lens solutions that are reportedly gentler for the environment and the wearer. Unlike conventional products, the company’s saline solution is dispensed by a safe nitrogen propellant, which means it contains no preservatives. Clear Conscience also offers an FDA-approved Multi-Purpose Solution that is benzalkonium chloride- and thimerasol-free. It can be used to disinfect, clean and store hard or soft contacts. WholeFoods Markets and other large natural goods stores stock Clear Conscience products, or they can be ordered online at the company’s website.

Meanwhile, Alcon, one of the largest providers of traditional lens solutions, has diversified its product line to include two preservative-free products, Unisol 4 and Pliagel, both which are available online at drugstore.com as well as at other large health products retailers.

CONTACTS: Contact Lens Council, (800) 884-4CLC, www.contactlenscouncil.org; Clear Conscience, (800) 595-9592, www.clearconscience.com; Perret Opticiens, www.perret-optic.ch/index_gb.htm; Alcon Labs, (800) 757-9195, www.alconlabs.com; drugstore.com.

Dear EarthTalk: Would removing the bald eagle from endangered species protection, as proposed by some environmental groups and the Bush administration, be considered an environmental victory? -- William Young, Chappaqua, NY

Just 30 years ago, the once-abundant bald eagle--America’s national symbol--was in danger of extinction in its primary habitat across the lower 48 states. Hunting, sprawl and poisoning from the agricultural pesticide DDT had conspired against this majestic raptor, despite safeguards in place under the Bald Eagle Protection Act of 1940. Fewer than 500 breeding pairs remained and the outlook was grim.

But with the banning of DDT in 1972 and the passage of the Endangered Species Act (ESA) in 1973, eagle populations began to rebound. By July 1995, the species had recovered to 5,700 pairs, and was upgraded from “endangered” to “threatened” status under the ESA. Today, biologists estimate that more than 7,600 breeding pairs inhabit the lower 48 states, and the Bush administration has proposed de-listing the species once and for all in 2005.

Conservation efforts have indeed made the eagle’s recovery possible, but nonetheless even the environmental community is split on whether or not de-listing the bird is a good idea. Some say that the eagle’s recovery has exceeded expectations and that de-listing would be the culmination and celebration of a great American conservation success story--proof that the ESA works.

“The species’ numbers have steadily increased over the past three decades, so much so that in some areas, such as the Chesapeake Bay region, there are hundreds more eagles today than there were prior to the DDT era,” says endangered species law expert Michael Bean of Environmental Defense, a non-profit group that was originally instrumental in the banning of DDT. Last spring, Environmental Defense lobbied the White House to put forth the most recent eagle de-listing proposal.

Additionally, some believe that GE foods can be hazardous to human health when ingested. Ronnie Cummins of the Organic Consumers Association says that GE foods have been linked to many health problems, including blood disorders and food allergies. For instance, a few years ago Pioneer Hi-Bred International, in order to boost the protein content of its products, developed a soybean using a gene from a Brazil nut. Independent tests on the GE soybean revealed that people allergic to Brazil nuts could have severe allergic reactions to the modified soybeans.

But other eagle advocates worry that key protections would no longer be in effect if de-listing were to take place. Kieran Suckling, executive director of the Center for Biological Diversity, says that earlier efforts by the Clinton White House to de-list the eagle stalled after federal biologists warned that contaminants in the environment and habitat loss were still preventing some eagle populations from achieving optimum reproduction rates. And budget cuts in the interim have meant that no additional eagle population monitoring has taken place. Without any new data to justify de-listing, Suckling and others consider taking endangered species protection away from the eagle at this point to be not only premature but also illegal.

Federal officials have put forth similar proposals to take the gray wolf and the grizzly bear off the threatened list as well. These great conservation success stories underscore how important the ESA has been. But as new, larger threats to wildlife--including habitat loss and global warming--loom, many are left wondering if we’re celebrating victory in the war against species loss a little too soon.

CONTACTS: Environmental Defense, (212) 505-2100, www.environmentaldefense.org; Center for Biological Diversity, (520) 623-5252, www.biologicaldiversity.org/swcbd/; U.S. Fish & Wildlife Service Endangered Species Program, http://endangered.fws.gov/.

Dear EarthTalk: I’ve heard that the solvents commonly used in commercial dry cleaning are unhealthy and unsafe for the environment. Is this true? -- Earl Eckstrom, Portland, OR

Studies show that perchloroethylene--the solvent used by the vast majority of dry cleaning establishments--is both hazardous to human health and injurious to the environment. For one, “perc,” as the solvent is commonly known in the industry, can have negative effects on the central nervous system. According to the National Institute of Environmental Health Sciences, short-term exposure to perc can lead to headaches, nausea, dizziness and memory problems.

The environmental organization Greenpeace found that perc breaks down into toxic byproducts like phosgene, vinyl chloride, carbon tetrachloride and trichloroacetic acid (TCA). Dr. Gina Solomon, a senior scientist at the Natural Resources Defense Council, says, “Phosgene is an extremely hazardous gas which evaporates and in closed spaces is potentially lethal. Vinyl chloride is a proven carcinogen and carbon tetrachloride is a known liver toxin.” And TCA has been linked to the extensive damage done to trees in the Black Forest in Germany, where it was used as an herbicide in the 1950s and 1960s.

While the use of rinse-aid to combat dishwasher streaking is no environmental crime, those concerned about the consumption of resources might think twice about the need for it. Mainstream rinse-aid, like dishwasher soap itself, contains phosphates in its cleaning agents. Wastewater containing phosphates which escapes sewage treatment can cause excessive algae growth in waterways which in turn pollutes drinking water and leads to marine “dead zones”--underwater environments deprived of oxygen and thus unable to support life. Consumers should keep in mind that dishwasher soaps, as well as laundry detergent and many other household items, also contain phosphates that can cause problems if not disposed of properly.

A Danish study by Kolstad, Brandt and Rasmussen revealed that pregnant dry cleaning workers are twice as likely to have a miscarriage as pregnant women in other professions. And the University of California at Berkeley found that male dry cleaning workers have more sperm abnormalities and a significantly lower sperm count than men not employed by the industry.

Less toxic alternatives to perc are beginning to take hold. Comet Cleaners, which has 350 locations in 17 states and Mexico, replaced perc a decade ago with the more benign petroleum solvent, Exxon D-2000. Other cleaners have switched over to Chevron-Phillips’ EcoSolv, a similar hydrocarbon-based alternative. Meanwhile, more than 200 cleaners--including Chicago’s Greener Cleaner--employ “wet cleaning,” a non-toxic, non-polluting alternative that uses biodegradable soap and water.

Perhaps the most promising non-toxic perc alternative is produced by GreenEarth Cleaning, which has patented its silicone-based dry cleaning solvent called Cyclic Silioxane. This product poses no threat to the environment or human health and simply degrades to sand, water and carbon dioxide. General Electric and Proctor & Gamble have formed a joint venture with GreenEarth to help dry cleaners worldwide switch over to this more benign alternative. At greenearthcleaning.com, consumers can search an international database to find dry cleaners in their area that are using the new solvent.

While the U.S. Environmental Protection Agency (EPA) regulates the use of perc under the Toxic Substances Control Act, the Clean Water Act and the Safe Drinking Water Act, states have been reticent to adopt phase-outs. The dry cleaning industry has mounted a strong lobby in favor of keeping perc legal, but consumer opposition is building, especially as more non-toxic alternatives are becoming available.

CONTACTS: Natural Resources Defense Council, (212) 727-2700, www.nrdc.org; Comet Cleaners, (817) 461-3555, www.cometcleaners.com; Green Earth Cleaning, (816) 926-0895, www.greenearthcleaning.com; EPA Perc Fact Sheet, www.epa.gov/opptintr/chemfact/f_perchl.txt.