Are there differences between the calculations for determining NAAQS attainment and the EPHT air quality indicator for ozone?
Yes. The calculation for the EPHT air quality indicator for ozone is based on exceedances of NAAQS in a county over a one-year period whereas the calculation for determining NAAQS attainment is based on the 3-year average of the fourth-highest daily maximum 8-hour average ozone concentrations measured at each monitor within an area2. The EPHT air quality indicator is based on monitoring data submitted by the MassDEP to US EPA’s Air Quality System, or AQS (http://www.epa.gov/ttn/airs/airsaqs/). EPHT data may also include air quality monitoring results during “exceptional events”, whereas the US EPA allows states to exclude certain “exceptional events” when assessing NAAQS attainment. Exceptional events may include chemical spills and industrial accidents, structural fires, and natural events (volcanoes and earthquakes, high wind events, wildfires). For example, data for several 2002 ozone exceedances were flagged as an “exceptional event”, because they were caused by emissions from a fo
Related Questions
- Are there differences between the calculations for determining NAAQS attainment and for determining the EPHT air quality measures for ozone?
- Are there differences between the calculations for determining NAAQS attainment and the EPHT air quality indicator for ozone?
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