National Ambient Air Quality Standards

National ambient air quality standards (NAAQS) are air quality standards whose purpose is to protect public health and the environment. The NAAQS are set by EPA for the six criteria pollutants: ozone, particulate matter, lead, carbon monoxide, nitrogen dioxide, and sulfur dioxide. Section 108 of the CAA requires EPA to identify criteria pollutants and set standards and Section 109 requires EPA to publish and promulgate regulations to implement the standards. The current standards can be viewed on the EPA's NAAQS Table.

After a standard is issued or changed, EPA and each state work together to assess whether the air quality in any areas of the state is violating the new/revised standard. This assessment is typically based on ambient air quality measurements performed in and near the state’s population centers. EPA makes the final decision on which areas, if any, to designate as not attaining a given standard. In general, designations of nonattainment areas for a specific standard are made final 2 years after the standard is issued.

Georgia’s current redesignated areas for the criteria pollutants are listed in the table below. Redesignated areas are areas that were formerly nonattainment but which have achieved the specific standard and have been redesignated to attainment by EPA. These areas have EPA-approved plans for maintaining attainment with the standard.

Georgia’s Redesignated Areas




Level of
ozone 2015 0.070 ppm 8 hours
Download this pdf file. Atlanta
ozone 2008 0.075 ppm 8 hours   Download this pdf file. Atlanta
ozone 1997 0.08 ppm 8 hours   Download this pdf file. Atlanta
Download this pdf file. Macon
Download this pdf file. Murray Co.
1997 15 µ g/m3 annual   Download this pdf file. Atlanta
Download this pdf file. Macon
Download this pdf file. Floyd Co.
Download this pdf file. Chattanooga
  1. The level given is for the primary standard. The level of the secondary standard is the same as the primary unless noted otherwise.
  2. Click on area name to see area map

Ozone Problem

Ground-level ozone, a primary ingredient in smog, is formed when volatile organic compounds (VOCs) and NOx react chemically in the presence of sunlight. Car, trucks, power plants and industrial facilities are primary sources of these emissions. Ozone pollution is a concern during the summer months when the weather conditions needed to form ground-level ozone – lots of sun and hot temperatures – normally occur. Ozone is unhealthy to breathe, especially for people with respiratory diseases and for children and adults who are active outdoors.

Fine Particulate Matter Problem

Fine particle pollution is a mixture of microscopic solids and liquid droplets suspended in air. Fine particles can be emitted directly (such as smoke from a fire) or formed in the atmosphere from power plant, industrial and mobile source emissions of gases such as sulfur dioxide and nitrogen oxides. Fine particles less than or equal to 2.5 micrometers in diameter (called PM2.5 and measuring about one-thirtieth the diameter of an average human hair), pose the greatest risk. These particles can be inhaled deep into the lungs, and some may even cross into the bloodstream.

Sulfur Dioxide - Annual Reports for EPA’s Data Requirements Rule for the 2010 1‑Hour SO2 NAAQS

According to EPA’s Data Requirements Rule for the 2010 1-Hour Sulfur Dioxide (SO2) Primary National Ambient Air Quality Standard (FR 80 51052), for any area where modeling of actual SO2 emissions serve as the basis for designating such area as attainment for the 2010 SO2 NAAQS, the air agency shall submit an annual report to the EPA Regional Administrator by July 1 of each year that documents the annual SO2 emissions of each applicable source in each such area and provides an assessment of the cause of any emissions increase from the previous year. The first report for each such area is due by July 1 of the calendar year after the effective date of the area’s initial designation.

A copy of the modeling files can be requested by sending an e-mail to Dr. Byeong-Uk Kim.