May 6, 2005
Thanks in part to cooler weather and an early start to the rainy season,
the region has experienced the cleanest year on record for particulate air
quality since monitoring began in 1987.
“Particulate pollution is shaping up as our most serious air pollutant,
responsible for a wide range of adverse health effects from increased
hospital admissions to increased premature deaths,” said Barry Wallerstein,
executive officer for the South Coast Air Quality Management District.
“While we are encouraged by the improving trend, we will need significant
additional controls and programs to meet federal health-based particulate
standards, particularly for fine particulates known as PM2.5.”
Last year, annual average levels for particulate matter PM10 and PM2.5
were the lowest since monitoring began for PM10 in 1987 and PM2.5 in 1999.
Even so, the region continues to exceed the US Environmental Protection
Agency’s health standard for both PM10 and PM2.5. (See following charts)
Bold horizontal lines indicate US EPA health standards.
Last year also was the cleanest on record for ozone, the region’s other
serious pollutant. That was also due in part to unseasonably cool weather
and weak atmospheric inversions that help trap smog.
Last year, the PM10 annual average health standard of 50 micrograms per
cubic meter (µg/m3) was exceeded at just one monitoring site – Rubidoux in
Riverside County – which registered 55.4 µg/m3. AQMD conducts regular
monitoring for PM10 and PM2.5 at approximately 20 stations throughout its
four-county jurisdiction.
AQMD will conduct a study this year in Rubidoux to identify any
additional local or county measures that can be implemented to help reduce
PM10 in the area.
The Los Angeles Basin has not exceeded the short-term PM10 standard
(measured over 24 hours) for a decade. The Coachella Valley area did exceed
the short-term PM10 standard on one windy day last year, but an EPA natural
events policy may allow that day to be excluded from consideration in
meeting the standard.
Particulate air quality trends indicate the region will approach the
federal PM10 standard for 2006 but will not achieve it without further
emission controls. Additional emission reductions are expected through
implementation of current and proposed rules.
Recent health studies prompted federal and state air agencies to review
annual and short-term particulate standards. The California Air Resources
Board recently revised the state standards for both PM10 and PM2.5 to better
protect health and the U.S. EPA is considering similar changes.
PM10 particles are 10 microns or smaller, and PM2.5 particles are 2.5
microns or smaller. One micron is one-thousandth of one millimeter. A
human hair is about 70 microns in diameter. PM10 and PM2.5 particles come
from a variety of mobile and industrial sources.
In other action today, the Board:
- Adopted a guidance document for use by local governments when
developing or revising their general plans. The document provides a list
of voluntary measures local governments can do to control air pollution
and reduce health risks in their communities, particularly those
associated with land use decisions. Many land use decisions made by local
governments represent opportunities to complement air quality regulations
in preventing or lowering air pollution impacts. The AQMD will distribute
the guidance document to local governments and continue outreach, as well
as develop a web page to provide resources to assist local governments in
addressing air quality issues;
- Conducted a pre-hearing for Proposed Rule 1401.1 – Requirements for
New and Relocated Facilities Near Schools;
- Approved additional funding to extend field monitoring for the
Multiple Air Toxics Exposure Study (MATES III) one additional year. Due
to the unusually high levels of rainfall this winter, there is a desire to
collect air toxics data during more normal meteorological conditions. The
additional monitoring will provide an understanding of the variability in
air toxic levels from year to year;
- Awarded contracts to cosponsor three projects to demonstrate and
advance plug-in hybrid technology in commuter vans and passenger cars.
The plug-in technology has the potential of improving engine performance
and mileage, and reducing vehicle emissions to near zero; and
- Awarded a contract for the purchase of a larger, transit-style
compressed natural gas (CNG) school bus, to be used along with an existing
smaller CNG school bus, in a demonstration and loaner program. The buses
will be available to school districts and school bus transportation
providers for a 30- to 45-day period to provide familiarity with the
characteristics of a CNG bus prior to purchase.
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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