National Ambient Air Quality Standards (NAAQS)

The National Ambient Air Quality Standards (NAAQS) define the maximum permissible concentrations for certain pollutants, known as criteria pollutants. Click on the pollutant name for the relevant DEQ factsheet.

Pollutant		Standard	Averaging Time	Level	Form
Carbon Monoxide (CO)		Primary	8-hour	9 ppm	Not to be exceeded more than once per year
			1-hour	35 ppm
Lead (Pb)		Primary and Secondary	Rolling 3 month average	0.15 μg/m³	Not to be exceeded
Nitrogen Dioxide (NO2)		Primary	1-hour	100 ppb	98th percentile (3 yr avg)
		Primary and Secondary	Annual	53 ppb	Annual mean
Ozone (O3)		Primary and Secondary	8-hour	0.070 ppm	Annual 4th-highest daily max 8-hr concentration (3 yr avg)
Particulate Matter	PM10	Primary and Secondary	24-hour	150 μg/m³	Not to be exceeded more than once per year (3 yr avg)
	PM2.5	Primary	Annual	9.0 μg/m³	Annual mean (3 yr avg)
		Secondary	Annual	15 μg/m³	Annual mean (3 yr avg)
		Primary & Secondary	24-hour	35 μg/m³	98th percentile (3 yr avg)
Sulfur Dioxide (SO2)		Primary	1-hour	75 ppb	99th percentile of 1-hour daily max concentrations (3 yr avg)
		Secondary	3-hour	0.5 ppm	Not to be exceeded more than once per year

Where do we stand in relation to the NAAQS?

These charts keep track of the highest values for continuously-monitored criteria pollutants for the current year. The charts are updated each weekday (quarterly for annual PM2.5). For data from previous years, visit our Past Air Data page.