Measure E2: Daily Air Quality

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• For the reported years 1998 to 2007, these results reflect the recent reduction of the eight-hour ozone standard from 0.08 ppm to 0.075 ppm, effective May 2008.
• The percentage of days that were designated as having “unhealthy” air quality (including days that were unhealthy for everyone as well as those that were unhealthy for sensitive groups) decreased between 1998 and 2007, dropping from an average of 6.0 percent in 1998-2002 to 4.6 percent in 2007. The percentage of days with “moderate” air quality was 12% in 1998 and 21% in 2007. Much of this increase is due to the adoption of a PM2.5 standard and implementation of widespread monitoring of PM2.5 in the late 1990s.
  • The coverage of monitoring for this measure, in terms of area and percentage of days monitored, increased between 1998 and 2007. Approximately 24 percent of children’s days of exposure to air pollutants were not monitored in 2007. This percentage includes days for which no AQI was reported in counties where the AQI is sometimes reported, as well as counties in which the AQI is not reported at all. On days that were monitored, in many cases only one or a few pollutants were monitored.

Related Measures:

• Respiratory Illnesses