Ozone National Ambient Air Quality Standard

Last modified Thursday, July 03, 2008 10:26

Unlike other gaseous air pollutants, ground level ozone is not directly emitted by any sources.  Ozone is formed when volatile organic compounds (VOCs) and nitrogen oxides (NOx) react with extreme sunlight.  Sources of ozone precursors include coal-fired power plants, gas stations, natural sources, and fuel combustion in cars and trucks.

Ozone impacts the respiratory system causing irritation to the nose, throat, and lungs.  The long term effects of ozone are due to the inflammation of the lungs when ozone is inhaled; this type of exposure can be compared to repeated sunburns and can lead to permanent scarring of lung tissue, loss of lung function, and reduced lung elasticity.

Over the last several decades, the country has witnessed a substantial increase in the number of automobiles and the associated increase in the number of vehicle-miles traveled (VMT). Atlanta has experienced tremendous growth, adding nearly a million people since the turn of the century.  As a result, ozone has become a particularly persistent problem. 

In Georgia, the ozone monitoring season is March 1 – October 31, when temperatures are the highest.  However, ozone is a problem year-round.  EPD maintains ozone monitoring data in Georgia.

The Clean Air Act has established a nonattainment area classification system for ozone based on the severity of the ozone problem. Deadlines to demonstrate attainment of the ozone standard vary by designation, along with the specific controls required to be implemented. The more severe the designation, the more time an area is provided to demonstrate attainment, but the implemented controls must be more stringent.

The current standard for 8-hour ozone is 0.075 ppm.  Learn more about ozone in Atlanta.  (PDF)

Redesignation
The 20-county metro region failed to meet the 8-hour ozone standard by June 15, 2007, the deadline set by the Clean Air Act.  As a result, the region was reclassified from a marginal to a moderate 8-hour ozone nonattainment area, effective April 7, 2008.  A revision to the SIP addressing CAA’s pollution control requirements is required no later than December 31, 2008.  The Atlanta region must attain the standard no later than June 15, 2010.