Combustion products are produced when something burns. Major indoor combustion pollutants include carbon monoxide (CO), nitrogen dioxide (NO2), polycyclic aromatic hydrocarbons (PAHs), and fine (PM2.5) and ultrafine particles (UFP). These pollutants result from burning-related activities in the home, including gas appliances and stoves, grills, smoking, motor vehicles running in attached garages, and the burning of wood, candles, and incense. Combustion products can also move indoors from outdoor air.

The two routes for reducing exposure to combustion products in homes are source control (to reduce the amount of pollutant in the first place) and improved ventilation (to remove the pollutants from the home).

Source Control  

Take special precautions when operating fuel-burning unvented space heaters.

• Use proper fuel and keep heater properly adjusted (avoid yellow-tipped flame).
• 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 areas and keep burners properly adjusted.

• Using a stove hood with a fan vented to the outdoors.
• Properly adjusted flame in gas stove (avoid yellow-tipped flame).
• For new stoves, use pilot-less ignition to prevent continuous gas burning.
• Never use a gas stove to heat your home.
• Always confirm flue in your gas fireplace is open when it in use.

Use proper manufacturer guidelines to minimize woodstove emissions. New stoves should have EPA emission certification.

• Door in old woodstoves should be tight-fitting.
• Use aged or cured (dried) wood only.
• Follow the manufacturer's directions for starting, stoking and putting out the fire.
• Do not burn pressure-treat wood – its toxic.

Ventilation Improvements

Lowering indoor air pollutants by ventilation results in an increase the amount of outdoor air coming indoors. However, for polluted outdoor environments, such as in urban areas, this may effectively increase indoor pollutants. Deciding on whether to open windows or increase central air delivery depends on the demand to ventilate indoors and to an extent, the known outdoor air quality. Very often the most effective way to improve indoor air quality is to eliminate individual sources of pollution or reduce their emissions.

More information

The California Air Resource Board has general information about combustion pollutants and specific information about combustion products in your home.

The US EPA has further information on combustion products and indoor air quality, as does the World Health Organization.