There are a number of gases formed during combustion; the material being burned will determine the specific gases and their concentration. The most common combustion gases found in houses are released during the burning of heating fuels.

Carbon Monoxide

Carbon monoxide (CO) is produced by the incomplete combustion of materials such as natural gas, wood, coal, oil, kerosene, gasoline, and tobacco.

Colorless and odorless, carbon monoxide is especially deadly because our bloodstream absorbs the gas readily. Even small amounts of carbon monoxide in the air can lead to an oxygen deficiency in the bloodstream. This can result in impaired vision and brain function, irregular heartbeat, headaches, nausea, weakness, confusion, and even death.

Unvented kerosene, propane and oil space heaters, fireplaces, wood and coal-burning stoves and furnaces are potential sources of carbon monoxide.

Sulfur Dioxide

Sulfur dioxide (SO2) is produced when sulfur-containing fuels are burned. It is colorless and can have an odor, depending on the concentration.

Sources include kerosene space heaters, natural-gas or fuel-oil appliances, wood stoves, and fireplaces. When it comes in contact with moist mucous membranes, sulfur dioxide forms sulfurous acid, which can be irritating to the nasal and respiratory tracts.

Nitrogen Dioxide

Nitrogen dioxide (NO2) sources include natural-gas and fuel-oil appliances, kerosene heaters, wood burning and cigarettes.

NO2 is highly toxic, irritating, has a pungent odor, and is reddish brown in color. Health effects include burning and choking sensations in the upper respiratory tract, changes in sensory perception, and irritation of eyes and skin.