California Adopts World’s Most Stringent PM Standards, June 20, 2002
The California Air Resources Board has adopted stricter new ambient air quality standards for particulate matter, in response to state legislation calling for a review of air standards.
The Air Resources Board, in a unanimous vote on June 20, 2002, adopted the following PM standards:
– A new annual average PM2.5 standard was established at 12 micrograms per cubic meter (µg/m3), not to be exceeded. This is considerably more stringent than the federal annual average PM2.5 standard of 15 µg/m3.
– The annual average PM10 standard was lowered from 30 µg/m3 to 20 µg/m3, not to be exceeded. This compares with the federal annual average PM10 standard of 50 µg/m3.
– The 24-hour PM10 standard of 50 µg/m3 was retained, as compared to the federal standard of 150 µg/m3.
–The 24-hour standard for sulfates of 25 µg/m3 was retained. There is no comparable federal standard.
Consideration of a 24-hour PM2.5 standard was deferred until 2003, pending a review of the impact of changes in statistical methods on study results. The staff, in response to the unanimous recommendation of the Air Quality Advisory Committee, had developed a proposal for a 24-hour PM2.5 standard of 25 µg/m3, not to be exceeded. This is considerably more stringent than the comparable federal standard of 65 µg/m3 98th percentile, which allows seven exceedances per year.
The Air Resources Board estimated that statewide attainment of the new standards would reduce premature deaths by approximately 6,500 per year in California.
The Children’s Environmental Health Protection Act passed by the California state legislature in 1999, requires the Air Resources Board, in consultation with the Office of Environmental Health Hazard Assessment, to “review all existing health-based ambient air quality standards to determine whether, based on public health, scientific literature, and exposure pattern data, these standards adequately protect the health of the public, including infants and children, with an adequate margin of safety.”
In 2003, the staff will consider revisions to the 24-hour PM2.5 standard, and in 2004, the ozone standard will undergo review.
The Air Resources Board [arb.ca.gov] offers information about the standards online.
