aNot to be exceeded more than once per calendar year.
bTo attain this standard, the expected annual average PM10 concentration at each monitor in an area must not exceed 50 µg/m3.
cTo attain this standard, the 3-year average of the annual average PM2.5 concentrations from single or multiple community-oriented monitors must not exceed 15 µg/m3.
dTo attain this standard, the 3-year average of the 98th percentile of 24-hr concentrations at each population-oriented monitor in an area must not exceed 65 µg/m3.
eTo attain this standard, the 3-year average of the fourth-highest daily maximal 8-hr average O3 concentrations measured at each monitor in an area over each year must not exceed 0.08 ppm.
fEPA has recently proposed to revise these standards (see 71 Fed. Reg. 2620 ).
SOURCE: EPA 2004a.