* Although preliminary annual statistics are continually released, SAGE Stats only provides final statistics, which are released in May of the following year. Report includes exceptional events; these events (such as wildfires) are not "reasonably controllable" and are hence excluded from assessments relating to air quality regulation, but they nevertheless affect air quality.
Years Available: 2000–2019
Permanent Link: http://data.sagepub.com/sagestats/4026
General Notes: *Median value shows the 50th percentile of counties reporting data to the Air Quality Statistics (AQS)Data Mart; it is not reflective of the entire country. **Hourly average concentrations measured by monitoring equipment and reported to AQS. Second-highest 1-hour values in the year, in parts per million by volume (ppm). For more on exceptional events, see http://www.epa.gov/ttn/analysis/exevents.htm