Bad Air: EPA lists counties not meeting ozone standards

Just in time for summer, the Environmental Protection Agency has released the list of counties not meeting Clean Air Act standards for ozone emissions. Ozone, commonly known as smog, can make it hard to breathe and also damages trees and plants.

The current ozone standard of 75 parts per billion (ppb) has been in place since 2008. The EPA identifies areas of the country, based on air quality monitoring data, that meet the standard, and those in “non-attainment” that do not meet the standard.

Most areas identified as non-attainment have been on the list previously. The EPA says ongoing efforts by many state and local governments to improve air quality are a big reason why more areas were not classified as non-attainment.

 The EPA groups states in 10 regions by their associated EPA regional office. An interactive map on the EPA website shows county designations by each state.

Ozone is primarily created through emissions from industrial facilities and power plants, motor vehicle exhaust, gasoline vapors and chemical solvents. It is airborne and can spread for hundreds of miles.

States and local jurisdictions are currently operating under relaxed standards for ozone emissions. In 2010, the EPA proposed tightening the standard to a range of 60-70 ppb. President Obama withdrew the tighter standards in 2011 to reduce regulatory burdens. But the standard will be revisited in 2013.