Air Quality Monitoring

"Ambient air" is the outside air that we all breathe. This term is specifically defined by EPA as "that portion of the atmosphere, external to buildings, to which the general public has access."

In the early 1970s, the EPA listed six major air pollutants that affected the quality of ambient air and established concentration limits for these pollutants. These limits are known as the National Ambient Air Quality Standards (NAAQS). Primary limits or standards were established to protect human health and secondary standards were established to protect human welfare and the quality of life. Through the years, the NAAQS have been revised and amended to account for evolving scientific understanding of air pollution and its impacts. Currently, the six criteria pollutants are:

  • Ozone (O3)
  • Particulate Matter (PM 2.5 and PM 10)
  • Carbon Monoxide (CO)
  • Sulfur Dioxide (SO2)
  • Nitrogen Dioxide (NO2)
  • Lead (Pb)

These six pollutants can cause serious human health problems (including premature mortality) and damage the environment and property. Common sources of these pollutants are coal-fired power plants, industrial manufacturing sources, and on-road and off-road vehicles. The national standards can be viewed on-line at the National Ambient Air Quality Standards (NAAQS) page. The North Carolina state standards can be viewed online at the NC Ambient Air Quality Standards page.


Monitoring Data by Pollutant          Monitoring Data by Site         

Map of Monitoring Locations          Current Air Quality Index



John C. Evans
Chief, Ambient Monitoring Section
Phone 919-707-8474
Fax 919-707-8474

Joette Steger, Ph.D.
Projects and Procedures Branch Supervisor
Phone 919-707-8449
Fax 919-707-8449

Jim Bowyer, Ph.D.
Laboratory Analysis Branch Supervisor
Phone 919-715-7484
Fax 919-733-0890

Derrick House
Electronics and Calibrations Branch Supervisor
Phone 919-715-1761
Fax 919-733-6578