Meteorological conditions conducive to regional high particulate matter episodes
- Environmental Protection Agency, Research Triangle Park, NC (United States)
Particulate matter (PM) originates from a variety of anthropogenic stationary and mobile sources as well as natural sources. They may be emitted directly or formed in the atmosphere by transformations of gaseous emissions such as sulfur oxides, nitrogen oxides, and volatile organic substances. The physical and chemical properties of PM vary greatly with time, region, meteorology, and source category. In this study, relationships between elevated regional PM{sub 10} concentrations in the US and the prevalent meteorological conditions are investigated. Six years (1988--1993) of PM{sub 10} and meteorological data nationwide are analyzed. Both synoptic and statistical analyses are applied to examine the association between PM{sub 10} and meteorological conditions. Special emphasis is put on the regional and seasonal differences. Analysis results suggest that the meteorologically conducive conditions for regional PM{sub 10} elevations in the US are quite different between the warm and cold seasons. The warm season episodes are essentially triggered by a stagnant high pressure system and a stationary front/trough, with conditions very similar to those associated with regional high ozone events. In the cold season, however, regional PM{sub 10} episodes are heavily influenced by steady higher winds associated with the outer rim of a stagnant high pressure system, a quasi-stationary front, or the backside of a slow-moving, cut-off low pressure system. Some very localized PM{sub 10} episodes observed over isolated source areas in some States appear to be influenced by mesoscale weather systems. Among the 60 regionwide PM{sub 10} episodic days observed in the AIRS data base during the 1988--1993 period, 32 days (or about 53%) occurred in the summer season. Synoptic analyses suggest that the summertime stagnant high pressure system is most conducive to both regional ozone and PM{sub 10} episodes.
- OSTI ID:
- 351010
- Report Number(s):
- CONF-970677--
- Country of Publication:
- United States
- Language:
- English
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