National Ambient Air Quality Standards and
Nonattainment Areas
 

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 at http://epa.gov/air/criteria.html.

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 nonattainment areas for the criteria pollutants are listed in the table below. Georgia is currently in attainment of the NAAQS that are not listed in the table. 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 Nonattainment Areas

Priority Pollutant Year Standard Issued Level of Standard1 Averaging Time Nonattainment Area2 Redesignated Area2
ozone

2008

0.075 ppm 8 hours Atlanta
(click for designation correspondence)

 

ozone 1997 0.08 ppm 8 hours

 

Atlanta
Macon
Murray Co.

particulate matter (fine) 1997/2006 15 µ g/m3 annual

Atlanta
Macon
Floyd Co.
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.