Particulate Matter

Particulate Matter on the Decline

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. Health risks range from mild respiratory and cardiovascular issues to premature death from heart and lung disease.

PM levels in metro Atlanta have been dropping steadily. Factors that have helped clean our air include improved vehicle fuel economy, cleaner burning fuels, better pollution controls on power plants and increasing use of natural gas in power plants instead of coal.

PM Levels in metro Atlanta (2001-2014)
PM Levels in metro Atlanta (2001-2014) – Each line on the graph above represents readings from one of the nine PM monitors around the Atlanta region.

PM Monitoring

The U.S. Environmental Protection Agency (EPA) 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. In 2005, 20 counties and parts of two others were designated in nonattainment for the 1997 annual PM standard (15 micrograms per cubic meter).

In December 2012, the USEPA set a new annual standard of 12 micrograms per cubic meter. The entire Atlanta region met this standard.

USEPA re-designated the region as in attainment for the 1997 annual standard in February, 2016. Since the region is also meeting the newer 2012 standard, transportation conformity requirements for PM are revoked.

ARC is studying how PM impacts people in the Atlanta region, especially those living near major roadways through its Atlanta Roadside Emissions Exposure Study, or AREES.