Air Pollution Episodes

Episodes are thought of as periods of poor air quality, lasting up to several days, often extending over a large geographical area. The best-known air pollution episodes are the result of unusual meteorological conditions, but there are also events or accidents, which are characterized by very high emissions over a relatively short period and may have anywhere from a local to a global character. There are particular types of air pollution that range from the smog of London and Los Angeles through the forest fire smoke and dust episodes that trouble Asia. There are indoor air pollution problems that have an episodic nature and expose our most vulnerable populations to air pollutants that have leaked indoors or have been generated by indoor materials or activities. Episodes are evident in the heterogeneity of temporal and spatial measurements of pollution concentrations. They have often triggered public and political awareness and have become the motivation for better air pollution regulations.