A Caution on Cups, Chlorine and Clouds.

Reusable Mugs, Bleach Alternatives and Acid Rain

What are the main causes of acid rain, and where are the highest concentrations found in the U.S.?

Jeff Ohmberger, Lincoln, NE

A vast medley of chemicals and pollutants can contribute to acid rain, but emissions of sulfur dioxide ([SO.sub.2]) and nitrogen oxide (NOX) are primarily to blame. While there are natural sources of these chemicals (volcanoes, cows), the vast majority of [SO.sub.2] and NOX emitted in North America, up to 95 percent by some estimates, is of human origin. Sources include transportation emissions, coal and oil power plants, and the burning of fossil fuels. These chemicals react with moisture in the atmosphere to make sulfuric and nitric acid, which then falls back to the Earth as precipitation--acid rain, acid snow, even acid fog.

According to Rona Birnbaum of the Environmental Protection Agency's acid rain division, the highest concentrations found in America are in western Pennsylvania and West Virginia. This is because of the enormous number of coal-fired power plants strung along the Ohio River, and wind patterns which push the pollutants westward. A map showing acid rain concentrations nationwide can be found at the National Atmospheric Deposition Program's website, http:// nadp.sws.uiuc.edu.

Individual behavior also contributes to acid rain. To make a difference reduce the amount of energy used in the home, and the amount of driving you do. CONTACT: Environmental Protection Agency, Acid Rain Program Information, 401 M Street SW, Mail Code 6204J, Washington, DC 20460/[phone].

How can I convince co-workers to switch from Styrofoam cups to reusable mugs?

Jennifer Quintana, Miami, FL

Styrofoam is actually Dow's trade name for polystyrene. There are two problems with polystyrene, involving both production and waste. During production, a blowing agent blows gas into the polystyrene. For years, chlorofluorocarbons (CFCs) were the agents--contributing to the destruction of the Earth's ozone layer. After the Montreal Protocol's ban on CFCs, slightly-more benign HCFCs replaced them. However, Ozone Action's Christopher Ball notes, "HCFCs are better for the ozone layer than CFCs, but they still cause problems." Because of this, HCFCs have also recently been banned, with their total phasing-out not expected until the year 2030. Carbon dioxide and pentane (a highly flammable chemical that contributes to smog) are also used as blowing agents.

On the waste issue, polystyrene products, including cups, don't biodegrade well and, if incinerated, produce toxic ash. To combat such problems, recycling programs are popping up, but not yet everywhere. The web page of the Polystyrene Packaging Council (http://www.polystyrene.com) lists available facilities.

Drinking from reuseable mugs, however, is an easy way to reduce waste and ease pressures on the ozone layer. If people can't be convinced to change their throw-away habits, try telling them that the mugs can save them money, too. Many national chains such as Starbucks and 7-11,and many college dining facilities, offer discounts to customers providing their own mugs. CONTACT: Ozone Action, 1621 Connecticut Avenue NW, Washington, DC 20009/[phone]; Polystyrene Packaging Council, 1801 K Street NW, Suite 600 K, Washington, DC 20006/[phone].

I use products containing bleach to clean moss and mildew from my deck and siding. Should I be concerned about the bleach runoff? Are there alternatives?

Biefke Vos, Bothell, WA

According to Jane Houlihan, senior policy analyst at the Environmental Working Group, bleach can pose many threats to the environment. "Because bleach affects the pH levels in water, fish and other organisms sensitive to fluctuations in pH may be harmed," she says. Houlihan adds that if your deck is pressure treated, it likely contains an arsenic preservative. When acidic cleansers come in contact with the wood, arsenic may be released into nearby soil or waterways. "If using bleach," says Mark Petruzzi, of the eco-consumer organization Green Seal, "the trick is to determine the minimum amount needed so that unnecessary environmental damage can be avoided." For environmentally-safe alternatives to bleach cleansers, Compliance Specialist's "Hyper-Ox," or the Clean Environment Company's "Mold and Mildew" are options. However, your safest and most convenient bet is to use a homemade solution of vinegar and water. Using a hard-bristled brush and the solution, clean the area and dry it completely, then apply an eco-friendly, mildew resistant paint or sealer (such as American Formulating Manufacturers' Safecoat WaterShield) on the surface for lasting results. CONTACT: Environmental Working Group, 1718 Connecticut Avenue NW, Suite 600, Washington, DC 20009/[phone]; Green Seal, 1400 16th Street NW, Suite 300, Washington, DC 20036-2215/[phone]; Compliance Specialist, [phone]; Clean Environment Company, [phone]; AFM, [phone].