page_title: Particulates
section_title: United States
hierarchical_section_title: Particulates / Regulation / United States
caption_attribution_description: English: A graph of particulate levels in the atmosphere as determined by the US Environmental Protection Agency
context_page_description: Particulates – also known as atmospheric aerosol particles, atmospheric particulate matter, particulate matter, or suspended particulate matter – are microscopic particles of solid or liquid matter suspended in the air. The term aerosol commonly refers to the particulate/air mixture, as opposed to the particulate matter alone. Sources of particulate matter can be natural or anthropogenic. They have impacts on climate and precipitation that adversely affect human health, in ways additional to direct inhalation.
  Types of atmospheric particles include suspended particulate matter; thoracic and respirable particles; inhalable coarse particles, designated PM₁₀, which are coarse particles with a diameter of 10 micrometers or less; fine particles, designated PM2.5, with a diameter of 2.5 μm or less; ultrafine particles; and soot.
  The IARC and WHO designate airborne particulates a Group 1 carcinogen. Particulates are the most harmful form of air pollution due to their ability to penetrate deep into the lungs, blood streams and brain, causing health problems including heart attacks, respiratory disease, and premature death.
context_section_description: The United States Environmental Protection Agency (EPA) has set standards for PM₁₀ and PM2.5 concentrations. (See National Ambient Air Quality Standards)
caption: Air quality trends in the United States
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