GreenWorks - Reducing Your Woodstove's Environmental Impacts

With the prices of oil on the rise this winter, everyone is concerned with keeping warm. For about a quarter of our state's wintertime population, this means stoking the fire in the woodstove or fireplace. While warm and comfort-ing, wood burning can take its toll environmentally, particularly in the air we breathe.

What we commonly refer to as "smoke" is actually unburned fuel. The smoke that leaves the chimney or escapes into the house consists of gases and small particles, some smaller than the period at the end of this sentence. Both the gases and small particle pollution can cause significant respiratory problems and aggravate heart conditions. Gases released during incomplete burns from stoves that are not tight or are poorly operated pose additional health risks.

Pollution from wood stoves is a particular concern in the winter when cold, stagnant air limits air movement. As wood burning increases on cold, clear, calm nights, smoke is unable to rise and disperse. Pollutants are trapped and concentrated near the ground, and the small size of the particles allows them to seep into houses through closed doors and windows.

The best way to reduce the health hazards of wood smoke is to minimize airborne emissions by burning the right fuel and striving to burn the fuel completely. A stove's design, its installation, and how it's operated are key to a clean burn. Whatever your stove type, here are some operational tips.

Use the Right Fuel. Wood seasoned for six months or more, depending on tree species and drying conditions, creates the hottest, cleanest burn. Wet and green wood tend to generate smoke, cause creosote build up, and re-lease less heat. Use kindling or loose paper only for starting fires. Avoid treated or painted wood, particle board, or plywood, which contain chemicals that become hazardous when burned and inhaled. Never burn household wastes such as plastics, gift wrap, color newsprint, diapers, magazines, or coated or laminated papers. When burned, these products produce smoke, odors, and release toxic fumes, and the remaining ash may be hazardous.

Maintain a Good Burn. Fill your firebox with enough wood for a good flame, but don't overload it. Without good air circulation, the combustible tars and gases in wood cannot burn. Long, lazy flames are a sign that your fire needs more air. Operate any internal fans according to the manufacturer's instructions since they tend to re-duce heat, and the fire must be hot for a complete burn. For a hot burn, use the right size wood for the stove width; four to eight inch diameter wood is appropriate for the width range of most stoves. Your fire is burning efficiently if there is little or no smoke coming out of the chimney. When the concentration of particulates in smoke is low, the gaseous emissions are also low.

Maintain Your Woodstove. Leaks in a stove reduce its efficiency and can cause indoor air pollution. Check all gaskets and seams annually and fix any problems. Check air controls for stiffness and baffles for warping. Consult your owner's manual for additional maintenance suggestions and how-to tips.

If you're in the market for another stove, buy a new one. Stoves sold on or after July 1, 1992 must meet certain emission standards for small particle pollution and carry the EPA Emission Certification label. Certified stoves reduce smoke emissions by as much as 90 percent, compared with conventional stoves, and are much more effi-cient. Make sure that the stove is properly sized for the space you need to heat, and have it installed professionally to ensure tightness, safety, and proper draft. Operate your stove only in accordance with the manufacturer's in-structions.

For more information on wood stoves and air quality, contact the N.H. Department of Environmental Services Air Resources Division at (603) 271-1370. For year round daily air pollution forecasts, for small particulate pollution, visit www.des.nh.gov/airdata/air_quality_forecast.asp. For information on wood stoves for residential heating, contact the N.H. Governor's Office of Energy and Community Services at (603) 271-2611.