| 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 ?g/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 ?g/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
Return to Annual Air Quality Report 2010
