| Sept. 28, 2006 This year’s
smog season is drawing to a close with 86 days of unhealthy air quality – a
number similar to that experienced during the past two years.
“Personal exposure to air pollution is diminishing but not at the
dramatic pace that we experienced during the past two decades,” said Barry
Wallerstein, executive officer for the South Coast Air Quality Management
District.
“This trend makes it imperative that we redouble our efforts to reduce
emissions, particularly from mobile sources, in order to meet upcoming
federal ozone and particulate matter standards.”
AQMD plans to release its updated blueprint for achieving healthful air –
the draft 2007 Air Quality Management Plan – in early October. Under state
and federal law, the plan must scientifically demonstrate how specific
future air pollution control measures can achieve the emissions reductions
needed to achieve health-based air quality standards.
As of Sept. 27, the Southland exceeded the federal 8-hour ozone health
standard on 86 days, compared to 83 days during all of 2005 and 88 days in
2004. (Smog season officially begins on May 1 and ends on Oct. 31. While
autumn’s cooler temperatures and shorter days dramatically reduce the
potential for ozone formation, next month may bring one or more additional
days exceeding the ozone standard.)
The peak 8-hour ozone concentration as of Sept. 27 was 0.143 parts per
million (ppm), slightly below the peak of 0.145 ppm experienced in 2005 and
2004. The 1-hour ozone average -- no longer a regulatory standard but still
an important air quality benchmark -- was exceeded on 35 days this year, up
from 31 days last year and 27 days in 2004.
The 2006 smog season peaked early this year due to unusually warm weather
patterns in June and July. Summer weather returned to normal in August and
September.
Weather plays a major role in smog levels from year to year, and for that
reason air quality trends need to be examined over a period of several years
to judge progress toward clean air goals.
Despite the strictest air quality requirements in the nation, Southern
California continues to have the worst overall air pollution. Two other
areas of the country – Houston and the San Joaquin Valley – also have severe
ozone problems and periodically surpass the Southland in the number of ozone
violations. This year Southern California again surpassed both Houston and
San Joaquin Valley with the worst air quality in the nation. As of Sept.
27, Houston exceeded the 8-hour ozone standard on 34 days and the one-hour
standard on 19 days. San Joaquin Valley violated the 8-hour ozone standard
on 82 days and the one-hour standard on 18 days as of the same date.
The U.S. Environmental Protection Agency has enacted an 8-hour ozone
standard, exceeded when ozone levels rise above 0.08 parts per million (ppm)
during an 8-hour average. It is tougher and more health protective than the
former one-hour standard, exceeded when ozone levels are above 0.12 ppm
during a one-hour average. Southern California must meet the 8-hour
standard by 2021
Ground-level ozone, a colorless and pungent gas, damages lung cells and
may be linked to permanent lung damage. (Ozone in the stratospheric “ozone
layer,” several miles above Earth, protects people from the sun’s harmful
radiation.) Ground-level ozone can cause short-term health effects
including chest pain, coughing, and nose and throat irritation, and is
linked to increased symptoms for those with asthma and bronchitis.
AQMD is the air pollution control agency for Orange County and major
portions of Los Angeles, San Bernardino and Riverside counties.
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