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New Hampshire Department of Environmental Services

Particle Pollution (Particulate Matter)

Particulate matter (PM), particulates, or particle pollution are general terms for solid or liquid particles found in the atmosphere. Particle pollution is broken down into categories based on the size of its diameter in micrometers (or microns). Total suspended particles (TSP) consist of all particles , regardless of size. "Coarse" particles (PMco arse) are larger than 2.5 microns in diameter and "fine" particles (PM2.5) are those less than 2.5 microns in diameter. PM10 consists of all particles smaller than 10 microns. For comparison, a human hair is approximately 70 microns in diameter. Some particles enter the air as solids while others form secondarily from condensing gases or as the result of a chemical reaction of gases, typically sulfur dioxide, nitrogen oxides, and volatile organic compounds. more...

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NH Department of Environmental Services | 29 Hazen Drive | PO Box 95 | Concord, NH 03302-0095
(603) 271-3503 | TDD Access: Relay NH 1-800-735-2964 | Hours: M-F, 8am-4pm

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