Ambient Air Quality

The Clean Air Act requires that the EPA must designate National Ambient Air Quality Standards (NAAQS) for outdoor air pollutants that may be detrimental to human health and/or the environment. These air pollutants can originate at multiple sources such as automobiles, power plants, combustion of fossil fuels, and manufacturing. Air quality is also decreased by emissions from filling up your car, dry cleaning, and painting.

Ambient air quality monitoring

It is one of ARAQMD’s duties to monitor outdoor ambient air quality for Medina, Portage, and Summit counties and to ensure that the designated thresholds for those air pollutants covered within the NAAQS are met. The criteria pollutants monitored by our air quality monitors are ozone, particulate matter, carbon monoxide, nitrogen dioxide, and sulfur dioxide. Originally it was also necessary to monitor lead and PM10, but levels of these have been well below the national standards so they are not presently being monitored.

The criteria pollutants are monitored through the use of multiple monitors specifically designed to analyze each specific pollutant. These monitors collect samples to determine the concentrations of the criteria pollutants. The concentration values are then compared to the standard to determine if air quality standards are being met. There are three types of monitors, continuous, intermittent, and speciation:

  • Continuous monitors collect data every day for a 24 hr. period and is downloaded at 8 A.M. and 4 P.M. to an EPA server. The criteria pollutants continuously analyzed are ozone, PM2.5, carbon monoxide, and sulfur dioxide.
  • Intermittent monitors are only run one of three days for a 24 hour period from 12 midnight to 12 midnight. Particulate matter (PM2.5 and PM10) is manually collected from a filter, weighed, and sent for further analysis. A similar process is used for analyzing lead.
  • Speciation monitors are only run one of six days for a 24 hour period from 12 midnight to 12 midnight. Data is manually accessed at these monitors and then sent for further analysis. This monitor uses filters to collect major components of particulate matter less than 2.5 micrometers (PM2.5). These major components are sulfate, nitrate, organics, elemental carbon, and soil. Salt is another major component if located at a coastal site.

Using the data gathered from the monitors, ARAQMD calculates and publishes the Air Quality Index. Further information about each of the individual pollutants and the Air Quality Index may be found at the sites listed below: