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Particulate Matter 10 (PM10) Overview
Particulate matter (PM) is a complex mixture of small, solid particles and liquid droplets in the air. PM10 is particulate matter that is 10 microns (μm) or less in diameter. It is a mixture of materials that can include soot, metals, salt, and dust. Major sources include:
- Wildfires or open burns
- Dust from construction sites, landfills, gravels pits, agriculture, and open lands
Air Quality Standards
The health-based, National Ambient Air Quality Standards (NAAQS) for PM pollution specify the maximum amount of PM present in outdoor air. The Environmental Protection Agency (EPA) developed different health-based NAAQS for PM10 and PM2.5, in part because the coarser PM10 can be filtered out in the nose and throat, while PM2.5 is able to bypass this filtration system and penetrate deeply into the lungs, resulting in more serious health effects. PM concentration is measured in micrograms per cubic meter, or µg/m3.
In 1987, the EPA set new air-quality standards for PM10 of 150µg/m3 over a 24-hour period and an average of 50 µg/m3 annually. EPA revoked the annual PM10 standard in 2006 because the agency couldn’t show any adverse impact to human health.