A general term for gases that are released by combustion of fuel and decomposition of organic matter and are often toxic. Almost all exhaust gases are produced by carbon-based fuels, so they consist of oxides of carbon, often also oxides of other ingredients, e.g., nitrogen, sulfur, as well as contaminants or additives to petroleum fuels. These are the principal ingredient of urban smog and environmental pollution. See also off-gassing.
Subjects: Public Health and Epidemiology.