American Lung Association (April 2000)

WHY IS WOODBURNING AN AIR POLLUTION PROBLEM?

In most areas of the country, woodburning from fireplaces and woodstoves is the largest source of particulate matter air pollution (PM) generated by residential sources. In some localities, fireplaces and woodstoves have been identified as the source of 80% or more of all ambient particles smaller than 2.5 microns in diameter (PM2.5) during the winter months. A large body of evidence links PM with adverse health outcomes, including excess mortality, especially among those with preexisting cardiopulmonary illness.

Fireplaces and woodstoves, and even special equipment such as wood pellet combustors and EPA Phase II Certified woodstoves, produce orders of magnitude more particulate matter than well-tuned oil or gas devices producing equivalent heat. Moreover, woodstoves routinely produce several times more air pollutants than original design values simply because of improper operation (including their misuse as incinerators for residential refuse), maintenance, and normal equipment degradation with use.

In addition to particulate matter, woodsmoke emissions contain components such as carbon monoxide; various irritant gases such as nitrogen dioxide, sulfur dioxide, hydrochloric acid, and formaldehyde; and chemicals known or suspected to be carcinogens, such as polycyclic aromatic hydrocarbons (PAHs), and dioxin.

Monitoring of airborne particulate matter and PAH levels in many residential areas across the country shows that exposure to these pollutants is consistent with the use pattern of residential wood combustion. The sites studied are far from industrial sources and the times of maximum pollutant levels do not correlate with local traffic activity. Outdoor PAH levels in such residential areas have reached 2 micrograms per cubic meter during holiday evenings - comparable to the maximum recorded PAH concentrations in secondhand tobacco smoke.

Studies have also shown that people using woodburning devices to heat their homes can be routinely exposed to excessive levels of fine particulate matter in their indoor air.

WHAT ARE THE HEALTH EFFECTS?

Findings from animal studies demonstrate a reduction in disease resistance associated with woodsmoke exposure. Woodsmoke exposure can disrupt cellular membranes, depress immune system activity, damage the layer of cells that protect and cleanse the airways, and disrupt enzyme levels.

The health effects of woodsmoke exposure include increased respiratory symptoms, increased hospital admissions for lower respiratory infections, exacerbation of asthma, and decreased breathing ability. Population studies have shown that young children, the elderly, and people with preexisting cardiopulmonary disease are most likely to be affected.

As a major contributor to particulate matter air pollution, woodsmoke can also be linked directly with a variety of other particulate matter-associated health effects, including increased risks of school absenteeism, emergency room visits and hospitalizations for cardiopulmonary conditions and premature death.

WHAT ARE THE SOLUTIONS?

The American Lung Association recommends that individuals avoid burning wood in homes where less polluting heating alternatives are available. The use of the least-polluting alternative heating methods and cleaner technologies should be promoted to provide useful heat, while minimizing any adverse health effects.

For consumers who are considering replacing their wood-burning appliances with gas-burning appliances, ALA recommends choosing vented appliances whenever possible, to minimize potential indoor air quality problems.

If you must burn wood, here are a few important steps to reduce harmful emissions from your fireplace or woodstoves:


Use the cleanest technology available. All woodstoves manufactured after the late 1980's must meet EPA-certified standards. These woodstoves give off less pollution, need lass fuel, and need cleaning less often than older, non-certified woodstoves.

Burn only clean, dry, seasoned hardwood. Wet wood does not burn well, and produces more smoke. Soft woods like pine produce more emissions and deposits inside your chimney.

Never burn painted or treated wood, trash or colored paper, which give off harmful chemicals and more smoke as they burn.

Keep your stovepipe and chimney clean, to prevent the buildup of creosote that can cause chimney fires and noxious emissions.