What is a criteria air pollutant?
A criteria air pollutant is an air pollutant that has had a National Ambient Air Quality Standard (NAAQS) established for it by the U.S. EPA. There currently 7 criteria pollutants: sulfur dioxide, nitrogen dioxide, carbon monoxide, ozone, lead, particulate matter less than 10 microns in diameter (PM 10), and particulate matter less than 2.5 microns in diameter (PM 2.5). Back to Top • What is the difference between a primary and secondary National Ambient Air Quality Standard? Primary standards are set to protect human health. Secondary standards are set to protect public welfare and take into consideration such factors as crop damage, architectural damage, damage to ecosystems, and visibility in scenic areas. Back to Top • How is the location of an air monitoring station decided? Delaware has had air monitoring sites located around the state since the late 1960s. The original focus of the monitoring network was on monitoring close to point sources (large facilities with high emissions)
