More information about particulate matter and its effects http://www.arb.ca.gov/html/brochure/pm10.htm California Environmental Protection Agency known as PM10 a measure known as PM10 California EPA: Air Pollution – Particulate Matter Brochure California Air Resources Board a measure known as PM10 http://www.arb.ca.gov/html/brochure/pm10.htm http://www.arb.ca.gov/html/brochure/pm10.htm Particulate Matter California EPA: Air Pollution – Particulate Matter Brochure California Air Resources Board