Current National Ambient Air Quality Standards (NAAQS) Table

<Air pollution>

Current National Ambient Air Quality Standards (NAAQS) Table

Pollutant [links to historical tables of NAAQS reviews]		Primary/Secondary	Averaging Time	Level	Form
Carbon Monoxide (CO)		primary	8 hours	9 ppm	Not to be exceeded more than once per year
			1 hour	35 ppm
Lead (Pb)		primary and	Rolling 3 month average	0.15 μg/m3	Not to be exceeded
		secondary
Nitrogen Dioxide (NO2)		primary	1 hour	100 ppb	98th percentile of 1-hour daily maximum concentrations, averaged over 3 years
		primary and	1 year	53 ppb	Annual Mean
		secondary
Ozone (O3)		primary and	8 hours	0.070 ppm	Annual fourth-highest daily maximum 8-hour concentration, averaged over 3 years
		secondary
Particle Pollution (PM)	PM2.5	primary	1 year	9.0 μg/m3	annual mean, averaged over 3 years
		secondary	1 year	15.0 μg/m3	annual mean, averaged over 3 years
		primary and	24 hours	35 μg/m3	98th percentile, averaged over 3 years
		secondary
	PM10	primary and	24 hours	150 μg/m3	Not to be exceeded more than once per year on average over 3 years
		secondary
Sulfur Dioxide (SO2)		primary	1 hour	75 ppb	99th percentile of 1-hour daily maximum concentrations, averaged over 3 years
		secondary	3 hours	0.5 ppm	Not to be exceeded more than once per year

 

■   References

National ambient air quality standards. https://www.epa.gov/criteria-air-pollutants/naaqs-table. Access date: 2024-03-01