Ambient Air Monitoring

About the Ambient Air Monitoring Branch


The Ambient Air Monitoring Branch develops, operates, maintains, and updates the Shelby County Air Monitoring Program in accordance with county, state, and federal monitoring requirements.  The air monitoring network is comprised of 27 monitors measured at 5 site locations in Shelby County.  The Shelby County Air Monitoring program began in the 1970s after the Clean Air Act was established.  The program has continued to expand over the years.  The most recent monitoring stations established are the National Core Monitoring Station (NCore), Near Road Monitoring Station, and Photochemical Assessment Monitoring Station (PAMS).  The NCore station located in the Shelby Farms area was established in 2009 to determine concentrations of high sensitivity precursor gases in representative rural and urban atmospheres.  In 2013, the Branch began operation of a Near Road monitoring station located along the campus of Southwest TN Community College.  This station was established based on new EPA revisions to a 1-hour National Ambient Air Quality Standard (NAAQS) for nitrogen dioxide (NO2).  In the summer of 2021, the Branch added PAMS at the NCore site.  This station was established to meet requirements set by the EPA on the revised 8-hour ozone NAAQS.

The Ambient Air Monitoring Branch currently includes monitoring and data reporting for the following EPA required pollutants:  carbon monoxide (CO), nitrogen dioxide (NO2), ozone (O3), particulate matter (PM10, PM2.5, and PM10-2.5), sulfur dioxide (SO2), total reactive oxides of nitrogen (NOy), speciated volatile organic compounds (VOCs), and carbonyls.  The Branch reports VOC and carbonyl data from June 1 thru August 31 of each year. All of the other pollutants are measured and reported year round.  The Branch also collects meteorological data for six parameters at its National Core Monitoring Station (NCore) and Photochemical Assessment Monitoring Station (PAMS).  These meteorological parameters are ambient temperature, barometric pressure, cloud mixing height, relative humidity, wind direction and wind speed.  Shelby County has the only air monitoring program in the State of Tennessee that operates a NCore and PAMS station. 

The Ambient Air Monitoring Branch uses the data management system Air Vision to store and report data to the EPA and other agencies.  The Air Monitoring Branch measures pollution levels for five of the six criteria pollutants that the EPA identified as pollutants that affect the nation’s health and welfare.  The six criteria pollutants are:  carbon monoxide, lead, nitrogen dioxide, ozone, particulate matter, and sulfur dioxide.  The only criteria pollutant that is not measured for in Shelby County is lead. This is due to the limited sources of lead-emitting facilities operating in Shelby County.  

Our Goals


The objective of the Shelby County Ambient Air Monitoring Branch is to protect the health and sustainability of Shelby County by identifying any violations to the NAAQS, locating the highest ambient pollution across the area, and determining the general background concentration.   The Branch will provide real-time monitoring of air pollution episodes, develop data for trend analysis, and provide information to the public on daily air quality conditions in the area. 


National Ambient Air Quality Standards (NAAQS)


The Clean Air Act which was established in 1970 and amended in 1990 requires the EPA to set NAAQS per 40 CFR Part 50 for certain air pollutants that are determined to contribute to air pollution that is harmful to the public health and environment.  View the online Online NAAQs Table to learn more about the NAAQS.