The measures presented here can be used to inform the public and policy makers of the degree of potential exposures within a state during a year.
The daily National Ambient Air Quality Standards (NAAQS) for Fine Particulate Matter (PM2.5) is 35 micrograms per cubic meter (mcg/m^3).
Person-days are units for a population-weighted measure to estimate the exposure to high levels of PM2.5 at the county level. Person-days are highly influenced by county populations. If two counties have the same number of days above the NAAQS, and one of the counties has a much larger population, that county will have more person-days above the NAAQS.
Measure Description:
- Percent of days with PM2.5 levels over the daily NAAQS of 35 mcg/m^3
- Number of person-days with PM2.5 over the daily NAAQS of 35 mcg/m^3