County and City Air Quality

This database reports annual summaries of Air Quality Index (AQI) values for counties and core based statistical areas (CBSA). (CBSAs, areas designated by the Office of Management and Budget (OMB), refer collectively to metropolitan statistical areas and micropolitan statistical areas and consist of the county or counties (or equivalent entities) associated with at least one core (urban area) of at least 10,000 population, plus adjacent counties having a high degree of social and economic integration with the core as measured through commuting ties.)

Data reported indicate overall air quality as they take into account all of the criteria air pollutants measured within a geographic area. The AQI includes all available pollutant measurements, although many areas have monitoring stations for some, but not all, of the pollutants. The summary values include both qualitative measures (days of the year having "good" air quality, for example) and descriptive statistics (median AQI value, for example).  Each category also contains the national standard to compare counties and CBSAs to this standard.