Soots are fine particles of carbon that are produced by the incomplete combustion of fossil fuels. The synonyms for soots include black carbon, particulate matter, carbonaceous aerosols, and diesel exhaust particles. Black carbon is a term used to describe soot particles that are visible to the naked eye and is often associated with air pollution. Particulate matter refers to any type of tiny pollutant that can be found in the air, including soot. Carbonaceous aerosols are similar to black carbon and refer to any type of particle that contains carbon. Diesel exhaust particles are soot particles that are specifically produced by diesel engines and can have adverse health effects.