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.
