Ambient Air Quality Standards

Ambient Standards

Ambient Air Quality Standards
Pollutant	Standard	Unit	Comments
Particulate Matter
PM10 - 24 hour	150	ug/m3	Primary and Secondary Standard: Maximum 24 – hour average concentration with not more than one expected exceedance per year.
PM2.5 - 24 hour	35	ug/m3	Primary and Secondary Standard: based upon the annual 98th percentile averaged over a three year period.
PM2.5 - Annual	15	ug/m3	Primary and Secondary Standard: Maximum expected annual arithmetic mean averaged over three years.
Sulfur Dioxide
Annual	0.030	ppm	Primary Standard: (80 micrograms per cubic meter of air), maximum annual arithmetic mean concentration.
24 hour	0.14	ppm	Primary Standard: (365 micrograms per cubic meter of air), maximum 24-hour average concentration not to be exceeded more than once per year.
3 hour	0.5	ppm	Secondary Standard: (1300 micrograms per cubic meter of air), maximum 3-hour average concentration not to be exceeded more than once per year.
Carbon Monoxide
8 hour	9.0	ppm	Primary Standard: (10 milligrams per cubic meter of air), maximum 8-hour average concentration not to be exceeded more than once per year.
1 hour	35.0	ppm	Primary Standard: (40 milligrams per cubic meter of air), maximum 1-hour average concentration not to be exceeded more than once per year.
Ozone
8 hour	0.080	ppm	Primary and Secondary Standard: Fourth highest maximum 8-hour average concentration.
Nitrogen Dioxide
Annual	0.053	ppm	Primary and Secondary Standard: (100 micrograms per cubic meter of air), maximum annual arithmetic mean concentration.
Lead
3 month	1.5	ug/m3	Primary and Secondary Standard: maximum arithmetic mean averaged over a calendar quarter.