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National Ambient Air Quality Standards (NAAQS)

The Air Toxics Program relies on delegated portions of the EPA program for permitting, compliance and enforcement, while emphasizing ambient monitoring to evaluate the air toxic concerns unique to Oklahoma.  Rules for the Air Toxics Program can be found in Subchapter 42 and the list of pollutants and standards for the program can be found in Appendix O.

The pollutants in Appendix O were selected because of their relevance to Oklahoma. Should the levels in Appendix O be exceeded, an “area of concern” could be designated, allowing resources to be focused on finding local solutions to that area.

Toxic Program

Pollutant
 Standard Averaging Time Level Form
Carbon Monoxide (CO)
 Primary 8-hour 9 ppm Not to be exceeded more than once per year
1-hour 35 ppm
Lead (Pb) Primary and Secondary Rolling 3 month average 0.15 μg/m³ Not to be exceeded
Nitrogen Dioxide (NO2)
 Primary 1-hour 100 ppb 98th percentile (3 yr avg)
Primary and Secondary Annual 53 ppb Annual mean
Ozone (O3) Primary and Secondary 8-hour 0.070 ppm Annual 4th-highest daily max 8-hr concentration (3 yr avg)
Particulate Matter
 PM10 Primary and Secondary 24-hour 150 μg/m³ Not to be exceeded more than once per year (3 yr avg)
PM2.5
 Primary Annual 9.0 μg/m³ Annual mean (3 yr avg)
Secondary Annual 15 μg/m³ Annual mean (3 yr avg)
Primary & Secondary 24-hour 35 μg/m³ 98th percentile (3 yr avg)
Sulfur Dioxide (SO2)
 Primary 1-hour 75 ppb 99th percentile of 1-hour daily max concentrations (3 yr avg)
Secondary Annual 10 ppb Annual mean (3 yr avg)

Where do we stand in relation to the NAAQS?

These charts keep track of the highest values for continuously-monitored criteria pollutants for the current year. The charts are updated each weekday (quarterly for annual PM2.5). Data presented in the charts is subject to further QA/QC and may differ from the formal attainment designations process, which usually occur after a NAAQS has changed. A list of Oklahoma’s attainment designations can be found in the Code of Federal Regulations in 40 CFR 81.337.

Air Data Report

DEQ also makes an annual Air Data Report after all data has gone through quality control, generally the summer following the year of sampling. Data for previous years are available upon request. Please contact the Monitoring section managers at 405-702-4100.

Last Modified on Jan 29, 2026
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