Fine particulate matter (PM) is a term for particles and liquid droplets suspended in the air. PM originates from a variety of sources including diesel trucks, power plants, wood stoves and industrial processes. The chemical and physical compositions of these various particles vary widely. Health risks include premature death from heart and lung disease, aggravation of heart and lung diseases and respiratory and cardiovascular effects.
PM Design Value by Year
USEPA sets standards for PM at both an hourly and annual level. The Atlanta region has been in nonattainment in the past for the annual value. On April 5, 2005 20 full counties along with two partial counties were designated nonattainment for the 1997 annual PM standard; the standard was set at 15 micrograms per cubic meter.
In December 2012, the USEPA set a new annual PM standard of 12 micrograms per cubic meter. The Atlanta region met this standard and no portion of the region was designated nonattainment for this newer standard.
USEPA approved a Maintenance Plan and redesignation request for the 1997 annual standard for the region on February 24, 2016. Since the Atlanta region is meeting the newer 2012 standard as well, effective October 24, 2016 transportation conformity requirements for PM are revoked.
PM will still have an impact on the health of people in the Atlanta region, especially those living near major roadways. To learn more about how ARC has been planning for near-road emissions, jump over to the AREES page.