International Regulation of Urban Smog Since the 1940s - Air Pollution and Global Warming: History, Science, and Solutions - page 179

Table 8.2. California ambient air quality standards (CAAQS) and U.S. federal primary and secondary national
ambient air quality standards (NAAQS), as of 2011

Federal Federal

California primary secondary

standard standard standard

Pollutant (CAAQS) (NAAQS) (NAAQS)

Ozone [O 3 (g)] a
1-hour average 90 ppbv b 120 ppbv b Same as primary

8-hour average 70 ppbv c 75 ppbv c Same as primary

Carbon Monoxide [CO(g)] a
8-hour average

9 ppmv 9 ppmv None

1-hour average 20 ppmv 35 ppmv None

Nitrogen Dioxide [NO 2 (g)] a
Annual arithmetic average 30 ppbv 53 ppbv Same as primary

1-hour average 180 ppbv 100 ppbv None

Sulfur Dioxide [SO 2 (g)] a
Annual average None 0.03 ppmv None

24 hours 0.04 ppmv 0.14 ppmv None

3 hours None - 0.5 ppmv

1 hour 0.25 ppmv 0.075 ppmv None

Particulate Matter ≤ 10 minDiameter (PM 10 ) a
Annual arithmetic average

20 gm − 3

None None

50 gm − 3 150 gm − 3 d 24-hour average Same as primary

Particulate Matter ≤ 2.5 minDiameter (PM 2.5 ) a
Annual arithmetic average

12 gm − 3 15 gm − 3 e

Same as primary

35 gm − 3 f 24-hour average None Same as primary

Lead [Pb(s)] a
30-day average

1.5 gm − 3 None None

0.15 gm − 3

Rolling 3-month average None Same as primary

gm − 3 Quarterly average None 1.5 Same as primary

Particulate Sulfates
24-hour average 25 gm − 3 None None

Hydrogen Sulfide [H 2 S(g)]
1-hour average

0.03 ppmv None None

Vinyl Chloride
24-hour average 0.01 ppmv None None

a

Criteria air pollutants.

b

Standard exceeded if the daily maximum 1-hour average concentration exceeds given value more than once per year, averaged over
3consecutive years. The California 1-hour standard applies in California. The federal standard applies only to areas designated as
nonattainment areas prior to the 1997 Clean Air Act revision.

c

Standard exceeded if the 3-year average of the fourth highest daily maximum 8-hour average ozone mixing ratio exceeds the given
value.

d

Standard exceeded if the 99th percentile of the distribution of the 24-hour concentrations for a period of 1 year, averaged over 3 years,
exceeds 150 gm − 3 at each monitor within an area.

e

Standard exceeded if the 3-year average of the annual arithmetic mean of 24-hour measured concentrations exceeds 15 gm − 3 .

f

Standard exceeded if the 98th percentile of the distribution of 24-hour concentrations measured for 1 year, averaged over 3 years, exceeds
35 gm − 3 at each monitor within an area.