Wood stoves emit hundreds of times more pollution than furnaces


December 05, 1990|By Susan McGrath | Susan McGrath,Los Angeles Times Syndicate

"SMOKE STACKS UP." "SPLIT WOOD NOT ATOMS." Remember when bumpers sported those stickers? The admonition summed up the back-to-nature philosophy of the early 1970s. Sort of like wearing natural fibers instead of polyester.

Now, all those natural-fibers folks are wearing 100 percent petrochemical products from Patagonia, and the Environmental Protection Agency is regulating your wood stove.

It's always something.

The EPA is protecting us from wood stoves because, unfortunately, they are a significant source of air pollution in many parts of the United States. To give you an idea of how significant, note that the only other consumer product regulated by performance standards set by the EPA is . . . your car.

Here are a few of the ingredients in that romantic, woodsy plume wafting from your chimney: carbon monoxide, which at low concentrations causes fatigue in healthy people and increases chest pain in people with chronic heart disease; nitrogen dioxide, formaldehyde and benzo-a-pyrene, which may cause emphysema and lung cancer; and tiny, airborne particles called particulates. The carcinogenic compounds in the smoke piggyback on the particulates, getting a ride deep into your lungs with every breath you take.

People at particular risk from exposure to wood stove smoke are fetuses, infants, children, pregnant women, elderly people and people with heart or respiratory disease.

Sounds a little reminiscent of cigarette smoke, doesn't it? In fact, living with a wood stove, or downwind from someone else's wood stove, can be a lot like living with a very heavy smoker. For example: A Michigan State University study found that preschool-age children who live in houses with wood stoves have twice the incidence of upper-respiratory infections.

Another study, conducted by University of Washington researchers, compared asthmatic preschool-age children in neighborhoods with high wood stove use (Group A) versus low-wood-stove use neighborhoods (Group B). The lung capacity of the Group A kids decreased during the winter. The Group B kids' lung capacity improved.

Nationwide, wood smoke accounts for only 4 percent of air pollution, according to the EPA. But in the heavily wooded Northwest, Northeast and Appalachian regions, wood smoke accounts for much more. On winter nights when the wind dies down, smoke from wood stoves in residential neighborhoods in these areas can account for 70 to 85 percent of air pollution.

In response to the problem, wood-stove manufacturers have cleaned up stoves considerably. These newer, high-tech stoves contain emissions-control devices that burn up the pollutants and earn them certification from the EPA. A catalytic converter, for example, chemically changes fuel molecules so that they burn at lower temperatures. Secondary combustion chambers remove pollutants from the smoke by burning them at higher temperatures.

The devices work beautifully -- in the laboratory. However, in my living room and yours, the stoves don't do as well. We don't stack our wood as precisely as lab technicians do. We don't ventilate the stove as well. We gum up the catalytic converter by burning rubbish. And we bank the fire at night, turning it into a smoldering pollution factory.

According to the most recent studies, commissioned by the U.S. Department of Energy, the EPA, the Canadian Combustion Research Laboratory and others, wood stoves stack up like this:

For every 1 gram of particulates put into the air by a natural-gas furnace, an oil furnace emits 2 grams, a pellet stove emits 100 grams, a certified wood stove emits 400-500 grams, and an old wood stove spews out a staggering 1,000 grams.

All of which brings me to that family room you are thinking of remodeling this winter. The wood stove? Cross it right off your shopping list.

Comparative heating-cost studies done by the Washington Energy Extension Service show that buying, installing and providing wood for a new wood stove isn't really any cheaper than available alternatives, such as natural gas and oil. If you need to heat an addition to the house, look into extending existing duct or radiator work, or even into installing electric baseboard heat.

If you find wood fires irresistible, use a fireplace. Because people tend to use these ornamentally (mostly because they are lousy heat generators), fireplaces do not contribute as much air pollution as wood stoves do.

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