Pollutant |
Averaging
Time |
California Standards1 |
National Standards2 |
Concentration |
Attainment Status |
Concentration3 |
Attainment Status |
Ozone |
8 Hour |
0.070 ppm
(137µg/m3) |
N9 |
0.075 ppm |
N4 |
1 Hour |
0.09 ppm
(180 µg/m3) |
N |
|
See footnote # 5 |
Carbon Monoxide |
8 Hour |
9.0 ppm
(10 mg/m3) |
A |
9 ppm
(10 mg/m3) |
A6 |
1 Hour |
20 ppm
(23 mg/m3) |
A |
35 ppm
(40 mg/m3) |
A |
Nitrogen Dioxide |
1 Hour |
0.18 ppm
(338 µg/m3) |
A |
|
|
Annual Arithmetic Mean |
0.030
ppm
(56 µg/m3) |
|
0.053
ppm
(100 µg/m3)
|
A |
Sulfur Dioxide |
24 Hour |
0.04 ppm
(105 µg/m3) |
A |
0.14 ppm
(365 µg/m3) |
A |
1 Hour |
0.25 ppm
(655 µg/m3) |
A |
|
|
Annual Arithmetic Mean |
|
|
0.030 ppm
(80 µg/m3) |
A |
Particulate Matter (PM10) |
Annual Arithmetic Mean |
20 µg/m3 |
N7 |
|
|
24 Hour |
50 µg/m3 |
N |
150 µg/m3 |
U |
Particulate Matter - Fine (PM2.5) |
Annual Arithmetic Mean |
12 µg/m3 |
N7 |
15 µg/m3 |
A |
24 Hour |
|
|
35 µg/m3
See Footnote 10
|
U |
Sulfates |
24 Hour |
25 µg/m3 |
A |
|
|
Lead |
Calendar Quarter |
|
|
1.5 µg/m3) |
A |
30 Day Average |
1.5 µg/m3) |
A |
|
|
Hydrogen Sulfide |
1 Hour |
0.03 ppm
(42 µg/m3 |
U |
|
|
Vinyl Chloride (chloroethene) |
24 Hour |
0.010 ppm
(26 µg/m3 |
No information available |
|
|
Visibility Reducing particles |
8 Hour(1000 to1800 PST) |
See
Footnote 8 |
U |
|
|
A=Attainment N=Nonattainment U=Unclassified
|
mg/m3=milligrams per cubic
meter |
ppm=parts per million |
µg/m3=micrograms per cubic
meter |
- California
standards for ozone, carbon monoxide (except Lake Tahoe), sulfur dioxide
(1-hour and 24-hour), nitrogen dioxide, suspended particulate matter
- PM10, and visibility reducing particles are values that are not to
be exceeded. The standards for sulfates, Lake Tahoe carbon monoxide,
lead, hydrogen sulfide, and vinyl chloride are not to be equaled or
exceeded. If the standard is for a 1-hour, 8-hour or 24-hour average
(i.e., all standards except for lead and the PM10 annual standard),
then some measurements may be excluded. In particular, measurements
are excluded that ARB determines would occur less than once per year
on the average. The Lake Tahoe CO standard is 6.0 ppm, a level one-half
the national standard and two-thirds the state standard.
-
National standards
other than for ozone, particulates and those based on annual averages
are not to be exceeded more than once a year. The 1-hour ozone standard
is attained if, during the most recent three-year period, the average
number of days per year with maximum hourly concentrations above the
standard is equal to or less than one. The 8-hour ozone standard is
attained when the 3-year average of the 4th highest daily concentrations
is 0.075 ppm (75
ppb) or
less. The 24-hour PM10 standard is attained when the 3-year average
of the 99th percentile of monitored concentrations is less than 150
µg/m3. The 24-hour PM2.5 standard is attained when the 3-year average
of 98th percentiles is less than 35 µg/m3.
Except
for the national particulate standards, annual standards are met if
the annual average falls below the standard at every site. The national
annual particulate standard for PM10 is met if the 3-year average falls
below the standard at every site. The annual PM2.5 standard is met if
the 3-year average of annual averages spatially-averaged across officially
designed clusters of sites falls below the standard.
- National
air quality standards are set by US EPA at levels determined to be protective
of public health with an adequate margin of safety.
-
In
June 2004, the Bay Area was designated as a marginal nonattainment area
of the national 8-hour ozone standard. US EPA lowered the
national 8-hour ozone standard
from 0.80 to 0.75 PPM (ie.e. 75 ppb) effective May 27, 2008. EPA will
issue final designations based upon the new 0.75 ppm ozone standard
by March 2010.
-
The national 1-hour ozone standard was revoked by U.S. EPA on June 15,
2005.
-
In April 1998, the Bay Area was redesignated to attainment for the national
8-hour carbon monoxide standard.
-
In June 2002, CARB established new annual standards for PM2.5 and PM10.
- Statewide
VRP Standard (except Lake Tahoe Air Basin): Particles in sufficient
amount to produce an extinction coefficient of 0.23 per kilometer when
the relative humidity is less than 70 percent. This standard is intended
to limit the frequency and severity of visibility impairment due to
regional haze and is equivalent to a 10-mile nominal visual range.
-
The
8-hour CA ozone standard was approved by the Air Resources Board on
April 28, 2005 and became effective on May 17, 2006.
- U.S
EPA lowered the 24-hour PM2.5 standard from 65 µg/m3 to 35
µg/m3 in 2006. EPA is required to designate the attainment
status of BAAQMD for the new standard by December 2009.
Contact
David Burch (415)749-4641 dburch@baaqmd.gov
Updated 5/29/2008
|