Wood may be cheap, but cost to air quality may be high

By Margo Sullivan
Staff writer

August 12, 2008 02:47 am

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With heating oil prices rising faster than smoke up the chimney, more residents are turning to wood as a primary source of heat for the winter ahead. While wood may be cheaper for homeowners, the cost in terms of air quality may be high.

No one yet knows the health consequences and the overall environmental toll if many people more people switch from oil and gas to wood. As of 2006, about 25 percent of New Hampshire households had a wood stove.

"It's too soon," said Kathy Brockett, education and outreach coordinator with the state Department of Environmental Services. "We don't know."

But Brockett did say New Hampshire is working with other states in the Northeast to zero in on pollution generated from burning wood. Of particular concern is the environmental impact from fireplaces and outdoor wood boilers, she said.

"With increasing energy prices, we are looking at the potential impact on air quality due to shifting use of fuels," she said. "We don't know what kind of a shift we may get."

In past years, government agencies have cautioned consumers about switching to alternative fuels, because the investment cost may outweigh any savings.

But for some, the issue is not money; it's about the environment and health, according to Paul Miller.

Miller is deputy director of Northeast States for Coordinated Air Use Management, the organization the state Department of Environmental Services uses to study air quality from wood burning.

The organization has not studied pollution inside the home from pellet or wood stoves, Miller said. But he did cite a New Zealand study, which found increased emissions inside schools heated with wood heat. He said that suggested "stuff outside gets inside."

Generally, Miller said, wood burns dirtier than gas or oil and spews more toxins and "fine particulates" into the air. These particulates can be embedded deep in the lungs and cause respiratory problems. They're also a risk to people with asthma, especially children, and are associated with premature death.

"If you assumed that someone switches from oil or gas by installing a new certified wood stove, fine particle pollution goes up by 85 to 150 times over that from an oil or gas furnace, respectively, gas being the cleanest," he said. "If someone starts using a pre-existing older wood stove (pre-certification era), particulate pollution goes up by 260 to 460 times."

The worst problems come from the outdoor wood boilers.

"If someone installs a new outdoor wood boiler to replace an oil or gas furnace, particulate matter pollution goes up by over 1,000 times," he said.

Miller said it doesn't take much wood burning to build up air pollution, especially on cold days when there's no wind.

"Even in rural areas of New Hampshire and Massachusetts, in hilly coves or valleys, it doesn't take much smoke to build up to pretty unhealthy levels," he said.

The U.S. Department of Agriculture has been funding wood-fired boilers in Vermont public schools, Miller said, with the "unintended consequence of swapping out cleaner, older units with something not well controlled or well designed."

Miller said the pollution from the boilers probably has balanced out any improvements in air quality due to the government's efforts to get rid of diesel in school buses.

The solution, according to the state Department of Environmental Services, is to buy clean-burning stoves certified by the federal Environmental Protection Agency. But state air pollution experts are worried people trying to beat the oil and gas prices may put an older stove back into service, even though it doesn't meet emission standards.

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