STOVES, HEATERS, FIREPLACES, AND CHIMNEYS

STOVES, HEATERS, FIREPLACES, AND CHIMNEYS

In addition to environmental tobacco smoke, other sources of
combustion products are unvented kerosene and gas space heaters,
wood stoves, fireplaces, and gas stoves. The major pollutants
released are carbon monoxide, nitrogen dioxide, and particles.
Unvented kerosene heaters may also generate acid aerosols.

Combustion gases and particles also come from chimneys and
flues that are improperly installed or maintained and cracked
furnace heat exchangers. Pollutants from fireplaces and wood
stoves with no dedicated outdoor air supply can be back drafted
from the chimney into the living space, particularly in
weatherized homes.

Health Effects of Combustion Products

Carbon monoxide is a colorless, odorless gas that interferes with
the delivery of oxygen throughout the body. At high
concentrations it can cause unconsciousness and death. Lower
concentrations can cause a range of symptoms from headaches,
dizziness, weakness, nausea, confusion, and disorientation, to
fatigue in healthy people and episodes of increased chest pain in
people with chronic heart disease. The symptoms of carbon
monoxide poisoning are sometimes confused with the flu or food
poisoning. Fetuses, infants, elderly people, and people with
anemia or with a history of heart or respiratory disease can be
especially sensitive to carbon monoxide exposures.

Nitrogen dioxide is a colorless, odorless gas that irritates
the mucous membranes in the eye, nose, and throat and causes
shortness of breath after exposure to high concentrations. There
is evidence that high concentrations or continued exposure to low
levels of nitrogen dioxide increases the risk of respiratory
infection; there is also evidence from animal studies that
repeated exposures to elevated nitrogen dioxide levels may lead,
or contribute, to the development of lung disease such as
emphysema. People at particular risk from exposure to nitrogen
dioxide include children and individuals with asthma and other
respiratory diseases.

Particles, released when fuels are incompletely burned, can lodge
in the lungs and irritate or damage lung tissue. A number of
pollutants, including radon and benzo(a)pyrene, both of which can
cause cancer, attach to small particles that are inhaled and then
carried deep into the lung.

Reducing Exposure to Combustion Products in Homes

Take special precautions when operating fuel burning unvented
space heaters.

Consider potential effects of indoor air pollution if you use an
unvented kerosene or gas space heater. Follow the manufacturer s
directions, especially instructions on the proper fuel and
keeping the heater properly adjusted. A persistent yellow tipped
flame is generally an indicator of maladjustment and increased
pollutant emissions. While a space heater is in use, open a door
from the room where the heater is located to the rest of the
house and open a window slightly.

Install and use exhaust fans over gas cooking stoves and ranges
and keep the burners properly adjusted.

Using a stove hood with a fan vented to the outdoors greatly
reduces exposure to pollutants during cooking. Improper
adjustment, often indicated by a persistent yellow tipped flame,
causes increased pollutant emissions. Ask your gas company to
adjust the burner so that the flame tip is blue. If you purchase
a new gas stove or range, consider buying one with pilotless
ignition because it does not have a pilot light that burns
continuously. Never use a gas stove to heat your home. Always
make certain the flue in your gas fireplace is open when the
fireplace is in use.

Keep wood stove emissions to a minimum. Choose properly sized
new stoves that are certified as meeting EPA emission standards.

Make certain that doors in old wood stoves are tight fitting. Use
aged or cured (dried) wood only and follow the manufacturer s
directions for starting, stoking, and putting out the fire in
wood stoves. Chemicals are used to pressure treat wood; such wood
should never be burned indoors. (Because some old gaskets in wood
stove doors contain asbestos, when replacing gaskets refer to the
instructions in the CPSC, ALA, and EPA booklet, Asbestos in Your
Home, to avoid creating an asbestos problem. New gaskets are made
of fiberglass.)

Have central air handling systems, including furnaces, flues,
and chimneys, inspected annually and promptly repair cracks or
damaged parts.

Blocked, leaking, or damaged chimneys or flues release harmful
combustion gases and particles and even fatal concentrations of
carbon monoxide. Strictly follow all service and maintenance
procedures recommended by the manufacturer, including those that
tell you how frequently to change the filter. If manufacturer s
instructions are not readily available, change filters once every
month or two during periods of use. Proper maintenance is
important even for new furnaces because they can also corrode and
leak combustion gases, including carbon monoxide. Read the
booklet What You Should Know About Combustion Appliances and
Indoor Air Pollution to learn more about combustion pollutants.
The booklet is available by contacting CPSC, EPA s IAQ INFO
Clearinghouse, or your local ALA. (See Where to Go for
Additional Information for contact information.)