A measurement of the ability to see and identify objects at different distances. Visibility reduction from air pollution is often due to the presence of sulfur and nitrogen oxides, as well as particulate matter
California Air Resources Board ARB (California Environmental Protection Agency), glossary of air pollution terms, Sacramento, CA, USA 2013. http://www.arb.ca.gov/html/gloss.htm, (Air Pollut - Amer) {594}