PM2.5 Concentration

PM2.5, also known as fine particle matter, refers to tiny particles in the air that are 2.5 micrometers or less in diameter, allowing them to penetrate the lungs. Particle matter can include a mixture of organical chemicals, wood, dust, soot, and metals; and can be released into the air from cars and trucks, factories, and wood burning and fires. Because PM2.5 can penetrate the lungs and bloodstream, it may cause many adverse health effects including lung and heart disease. Children, the elderly, and persons suffering from cardiopulmonary disease, asthma, and chronic illness are the most susceptible to health complications from PM2.5. As such, it is important for communities and policymakers to understand air quality levels in order to anticipate adverse health outcomes as a result of air pollution, which can frequently be a direct result of local infrastructure and other structural decisions. 

The California Air Resources Board measures PM2.5 concentrations in the air from air monitoring stations around the state of California. The U.S. Environmental Protection Agency (EPA) has set a standard of 12 micrograms of PM2.5 per cubic meter of air (12 µg/m3) as an acceptable average annual concentration.