|
Table 1. Ambient Air Quality
Standards
|
|
Pollutant |
Averaging Time |
California Standards1 |
Federal Standards2 |
|
Concentration3 |
Method4 |
Primary3, 5 |
Secondary3, 6 |
Method7 |
|
Ozone (O3) |
1 Hour |
0.09 ppm
(180 µg/m3)
|
Ultraviolet Photometry |
--
|
Same as Primary Standard |
Ultraviolet
Photometry |
|
8 Hour |
0.070 ppm
(137 μg/m3)* |
0.075 ppm
(147 µg/m3)
|
Respirable
Particulate
Matter
(PM10) |
24 Hour |
50 µg/m3 |
Gravimetric or
Beta Attenuation |
150 µg/m3 |
Same as Primary Standard |
Inertial Separation
and Gravimetric
Analysis |
|
Annual
Arithmetic
Mean
|
20 µg/m3 |
-- |
|
Fine Particulate
Matter
(PM2.5)
|
24 Hour |
No
Separate State Standard |
35 µg/m3 |
Same as Primary Standard |
Inertial Separation
and Gravimetric
Analysis |
|
Annual Arithmetic Mean |
12 µg/m3 |
Gravimetric or
Beta Attenuation |
15.0 µg/m3 |
|
Carbon
Monoxide (CO)
|
8 Hour |
9.0 ppm
(10 mg/m3)
|
Non-Dispersive
Infrared Photometry
(NDIR) |
9 ppm
(10 mg/m3)
|
None |
Non-Dispersive
Infrared Photometry
(NDIR) |
|
1 Hour |
20 ppm
(23 mg/m3)
|
35 ppm
(40 mg/m3)
|
8 Hour
(Lake Tahoe) |
6 ppm
(7 mg/m3)
|
-- |
-- |
-- |
|
Nitrogen
Dioxide
(NO2)
|
Annual Arithmetic Mean
|
0.030 ppm
(57 µg/m3) |
Gas Phase
Chemi-luminescence |
0.053 ppm
(100 µg/m3)
|
Same as Primary Standard |
Gas Phase
Chemi-luminescence |
|
1 Hour |
0.18 ppm
(339 µg/m3)
|
-- |
|
Sulfur
Dioxide
(SO2)
|
Annual Arithmetic Mean |
-- |
Ultraviolet
Fluorescence |
0.030 ppm
(80 µg/m3)
|
-- |
Spectro-photometry
(Pararosaniline
Method) |
|
24 Hour |
0.04 ppm3
(105 µg/m3)
|
0.14 ppm
(365 µg/m3)
|
-- |
|
3 Hour |
-- |
-- |
0.5 ppm
(1,300 µg/m3)
|
|
1 Hour |
0.25 ppm
(655 µg/m3)
|
-- |
-- |
-- |
|
Lead8 |
30 Day
Average
|
1.5 µg/m3 |
Atomic Absorption |
-- |
-- |
|
|
Calendar
Quarter
|
-- |
1.5 µg/m3 |
Same as Primary Standard |
High Volume
Sampler and Atomic
Absorption |
|
Rolling 3-month Average9 |
-- |
0.15 µg/m3 |
|
Visibility
Reducing
Particles
|
8 Hour |
Extinction coefficient of 0.23 per kilometer — visibility of ten miles or
more (0.07 — 30 miles or more for Lake Tahoe) due to
particles when relative humidity is less than 70 percent. Method: Beta
Attenuation and Transmittance through Filter Tape. |
No Federal Standards |
|
Sulfates |
24 Hour |
25 µg/m3 |
Ion Chromatography |
|
Hydrogen
Sulfide
|
1 Hour |
0.03 ppm
(42 µg/m3)
|
Ultraviolet
Fluorescence |
|
Vinyl Chloride8
|
24 Hour |
0.010 ppm
(26 µg/m3)
|
Gas
Chromatography |
|
California Air Resources Board (11/17/08) |
Notes:
- California standards for ozone, carbon monoxide (except Lake
Tahoe), sulfur dioxide (1 and 24 hour), nitrogen dioxide,
suspended particulate matter—PM10, PM2.5, and visibility
reducing particles, are values that are not to be exceeded. All
others are not to be equaled or exceeded. California ambient air
quality standards are listed in the Table of Standards in
Section 70200 of Title 17 of the California Code of Regulations.
- National standards (other than ozone, particulate matter,
and those based on annual averages or annual arithmetic mean)
are not to be exceeded more than once a year. The ozone standard
is attained when the fourth highest eight hour concentration in
a year, averaged over three years, is equal to or less than the
standard. For PM10, the 24 hour standard is attained when the
expected number of days per calender year with a 24-hour average
concentration above 150 μg/m3 is equal to or less than one. For
PM2.5, the 24 hour standard is attained when 98 percent of the
daily concentrations, averaged over three years, are equal to or
less than the standard. Contact U.S. EPA for further
clarification and current federal policies.
- Concentration expressed first in units in which it was
promulgated. Equivalent units given in parentheses are based
upon a reference temperature of 25°C and a reference pressure of
760 torr. Most measurements of air quality are to be corrected
to a reference temperature of 25°C and a reference pressure of
760 torr; ppm in this table refers to ppm by volume, or
micromoles of pollutant per mole of gas.
- Any equivalent procedure which can be shown to the
satisfaction of the ARB to give equivalent results at or near
the level of the air quality standard may be used.
- National Primary Standards: The levels of air quality
necessary, with an adequate margin of safety to protect the
public health.
- National Secondary Standards: The levels of air quality
necessary to protect the public welfare from any known or
anticipated adverse effects of a pollutant.
- Reference method as described by the EPA. An “equivalent
method” of measurement may be used but must have a “consistent
relationship to the reference method” and must be approved by
the EPA.
- The ARB has identified lead and vinyl chloride as 'toxic air
contaminants' with no threshold level of exposure for adverse
health effects determined. These actions allow for the
implementation of control measures at levels below the ambient
concentrations specified for these pollutants.
- National lead standard, rolling 3-month average: final rule
signed October 15, 2008.
California Air Resources Board (11/17/08) | For more
information please call ARB-PIO at (916) 322-2990
Download this table in a printable PDF format:
aaqs.pdf
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