Balancing wood smoke and health

    In Maine, with cold winters and a forested landscape, wood is an obvious choice for home heating. Wood continues to be plentiful and has been used to heat dwellings since the first people began to live here.     All wood smoke, whether visible or not, can affect the health of everyone in the neighborhood. During the winter, wood smoke contributes to higher particle pollution values when conditions trap local emissions near the ground. ‘Wood smoke’ found indoors may come directly from a woodstove/fireplace or from outdoor wood smoke that has penetrated the building.
    Wood smoke contains harmful chemical substances such as: carbon monoxide, nitrogen oxides, volatile organic compounds (VOCs), dioxin, and inhalable particles. Some of the VOCs are irritating, toxic, and/or cancer causing. The biggest health threat from wood smoke comes from ‘particle pollution’ — tiny particles that remain airborne. Particle pollution contains many of the chemical substances mentioned above. These microscopic particles 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. Particle pollution can also aggravate chronic heart and lung diseases and is linked to premature deaths in people with these chronic conditions.
    There are ways we can all reduce our impact on air quality in our neighborhoods. Burn seasoned firewood in a manner that promotes complete combustion to reduce the amount of pollution emitted. Small, hot fires are better than large smoldering fires. To maintain your fire in the proper temperature range, use a stovepipe thermometer, an inexpensive device that sticks to the pipe magnetically. For improved draft and combustion, as well as safety, the chimney or stack should be cleaned as directed by the manufacturer.
    Another important recommendation is not to install any device, such as a “rainhat”, which impedes or reduces the vertical momentum of smoke out the stack. Vertical momentum helps to spread the wood smoke over a greater volume of air and also pushes wood smoke higher above the ground thus diluting concentrations, especially at ground level. Newer woodstoves and fireplace inserts, which have been approved by the EPA, emit less particle pollution and produce much more heat per unit of wood than older models ultimately paying for their replacement after a few years. Pellet wood stoves are much cleaner than any other wood burning appliance. All wood burning appliances should be the proper size for the job.
    People with respiratory and/or heart disease, the elderly and children should take precautions when air quality is likely to be poor. The Maine Department of Environmental Protection forecasts air quality year-round using the Air Quality Index (AQI). These forecasts and much more information can be found at www.mainedep.com click on ‘Maine Air Quality Forecast’. A brief forecast discussion can also be heard by dialing (800) 223-1196. So “Give A Hoot, Don’t Pollute” and “Keep an eye on the AQI.”
    This column was submitted by Martha Webster, a meteorologist and air quality forecaster with the Maine Department of Environmental Protection’s (DEP) Bureau of Air Quality. In Our Back Yard is a weekly column of the DEP. E-mail your environmental questions to infoDEP@maine.gov or send them to In Our Back Yard, Maine DEP, 17 State House Station, Augusta, ME 04333.