Source:http://linkedlifedata.com/resource/umls/id/C0457784
NCI: The generic term used for a type of air pollution. It consists of complex and varying mixtures of particles suspended in the air such as fine solids such as dirt, soil dust, pollens, molds, ashes, and soot; and aerosols that are formed in the atmosphere from gaseous combustion by-products such as volatile organic compounds, sulfur dioxide and nitrogen oxides. Particles of special concern to the protection of lung health are those known as fine particles, less than 2.5 microns in diameter.