Are there differences between the calculations for determining NAAQS attainment and for determining the EPHT air quality measures for ozone?
Yes. The calculation for the EPHT air quality measures for ozone (i.e., the number of days that the ozone NAAQS is exceeded and the number of total number of persons living in a county when the ozone NAAQS is exceeded over a one year period) is based on the number of days that the highest daily maximum 8-hour ozone concentration exceeds the 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 area. Both the NAAQS and the EPHT air quality measures are based on monitoring data submitted by the MassDEP to US EPAs 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 spill
Related Questions
- Are there differences between the calculations for determining NAAQS attainment and the EPHT air quality indicator for ozone?
- Are there differences between the calculations for determining NAAQS attainment and the EPHT air quality indicator for PM2.5?
- How is attainment of the National Ambient Air Quality Standard (NAAQS) for ozone determined using monitoring data?
