Full text of report
homes are affected
furnaces, as well
as the health
implications for the
families living inside
homes impacted by
In this report, Environment and Human Health, Inc. (EHHI)
explains its study, which measured potential wood smoke inhalation
by people living in homes in the vicinity of outdoor wood furnaces
(OWFs), also known as outdoor wood boilers (OWBs). EHHI’s
study monitored levels of PM2.5 and PM0.5 particles in each house
for 72 hours.
The U.S. Environmental Protection Agency (EPA) has shown that
PM2.5 and PM0.5 are the most common size particles in wood
smoke. PM2.5 and smaller cause the greatest health impacts because
they are small enough to go deep inside the lungs, where they can not
only damage the lungs, but also pass through into the blood stream, delivering their toxins throughout the body. EHHI’s study was performed over three days, for 72 hours per house, in each house that was monitored. This is the only study of its kind to date.
Key background information about wood smoke:
- Large amounts of wood smoke, like the plumes from OWFs,
cannot be kept out of neighboring houses, even those with tight
windows and doors.
- Wood smoke has many of the same components as cigarette
smoke and, therefore, these exposures pose a real health risk for
families living in the vicinity of OWFs.
- Wood smoke is a complex mixture of chemicals and particulates.
It contains carbon monoxide and other organic gases, particulate
matter, chemicals and some inorganic gases. Some of these
compounds are toxic (aldehydes and phenols) and some are
known carcinogens (benzopyrene and cresols).
- Wood smoke contains carbon monoxide (CO) gas, which at low
levels can lead to serious health problems for individuals with
compromised heart and circulatory conditions.
Large amounts of
wood smoke, like the
plumes from OWFs,
cannot be kept out of
even those with tight
windows and doors.
- Particulate matter in wood smoke that is less than 10 microns in
diameter finds its way into the alveoli in the lungs. Once in the
alveoli, the particulate matter can cause structural and chemical
changes, which interfere with oxygen uptake. As well, the toxic
compounds and carcinogens enter into the bloodstream by way
of the alveoli of the lungs.
- Episodes of short-term exposures to extreme levels of fine
particulates from wood smoke and other sources, for periods
as short as two hours, produce significant adverse health
- Wood smoke interferes with normal lung development in infants
and children. The components of smoke increase children’s risk of
lower respiratory infections, such as bronchitis and pneumonia.
Wood smoke exposure can depress the immune system and
damage the layer of cells in the lungs that protects and cleanses
- Wood smoke causes coughs, headaches, and eye and throat
irritation in otherwise healthy people. For vulnerable populations,
such as people with asthma, chronic respiratory disease and those
with cardiovascular disease, wood smoke is particularly
harmful—even short exposures can prove dangerous.
- Children and the elderly have the highest sensitivity to wood
smoke. However, no age group is without risk for respiratory
problems, including asthma and chronic obstructive pulmonary
disease (COPD), that result from breathing wood smoke. The
effects are cumulative.
- The air impact of health exposure to wood smoke is increased
two-fold during periods with stagnant air. Under such conditions,
the inhaled dose levels of particulates within houses approach the
hazardous level found in regulated work sites by OSHA. EHHI
found smoke entering houses, every day, at even higher levels.
The Dangers to Health from
A study by the
Washington in Seattle
showed that 50 to 70
percent of the
outdoor levels of
wood smoke were
entering homes that
were not burning
wood. The EPA
performed a similar
study in Boise, Idaho,
with similar results.
- The particulate matter and gases in wood smoke are so small that
windows and doors cannot keep them out—even the newer
energy-efficient, weather-tight homes cannot keep out wood
smoke. This is consistent with reports from people in the EHHI
study who say their children awaken in the middle of the night
having difficulty breathing.
- In 2009, the state of Massachusetts commissioned a study on the
environmental impacts of burning wood for electricity. That
study, conducted by the Manomet Center for Conservation
Sciences, has now been released. The Manomet study shows that,
per unit, wood releases more climate-damaging gases than coal.