Definitions for "Criteria pollutant"
One of a group of air pollutants regulated by EPA on the basis of criteria (information on health and/or environmental effects of pollution). Criteria air pollutants are widely distributed all over the country.
The Clean Air Act requires US Environmental Protection Agency (EPA) to establish “national ambient air quality standards”’ or NAAQS (expressed as concentration in air) for all “criteria pollutants.” Criteria pollutants are those pollutants that US Environmental Protection Agency (EPA) has determined (1) “cause or contribute to air pollution which may reasonably be anticipated to endanger public health or welfare,” and (2) exist in ambient air as a result of “numerous or diverse mobile or stationary sources.” EPA has identified the following as criteria pollutants: ozone, nitrogen oxides (NOx), sulfur dioxide (SO2), particulate matter (PM), fine particulate matter (PM 2.5), carbon monoxide (CO), and lead.
One of the six pollutants for which EPA is required to set National Ambient Air Quality Standards to protect human health and welfare. Criteria pollutants include ozone (ground-level), carbon monoxide, particulate matter, sulfur dioxide, lead, and nitrogen oxides. They are called "criteria" pollutants because the Clean Air Act required EPA to describe the criteria for setting or revising standards.