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Name: particulate matter less than 2.5 micrometers in diameter
Acronym: PM2.5
Description: Burden of particulate matter less than 2.5 micrometers (µm) in diameter (ug/m3). Particles less than 2.5 micrometers in diameter are called "fine" particles. These particles are so small they can be detected only with an electron microscope. Sources of fine particles include all types of combustion, including motor vehicles, power plants, residential wood burning, forest fires, agricultural burning, and some industrial processes. On September 21, 2006, EPA revised its National Ambient Air Quality Standard for PM 2.5 by significantly strengthening the 24-hour standards from 65 micrograms per cubic meter (µg/m3) to 35µg/m3. Thousands of scientific studies have linked exposure to these tiny particles - approximately 1/30th the size of a human hair - with serious human health problems including premature death in people with heart and lung disease; nonfatal heart attacks; and increased hospital admissions and doctor and emergency room visits for respiratory and cardiovascular disease.
Type: Noun
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Term has: Unit