There are presently 21 areas that violate
the current PM-10 standard. The standard for PM10 limits PM10
concentrations to 150 µg/m3 based on a 24-hour average.
The annual PM-2.5 standard (2012) was 12 ug/m3 and was changed
to 9 ug/m3 in 2024. The level
of the 24-hour PM-2.5 standard (2006) is 35 micrograms per cubic
meter (µg/m3). Maps
of the EPA's PM-10 and PM-2.5 designations for nonattainment
can be reviewed by clicking here.
