California Air Resources Board

SACRAMENTO – The California Air Resources Board (ARB) Thursday passed new, stricter standards for particulate matter (PM), the tiny dust-like particles that represent a danger to human health.

"This is an important step because these particles seriously impact human health, particularly infants, children, the elderly and those with existing heart or lung problems," said ARB Chairman, Dr. Alan Lloyd.

These particles are so small they can by-pass the body's defenses and lodge in the lungs. One 10 micron particle is one-seventh the size of a human hair. ARB calculations show that statewide attainment of the new standards would reduce premature deaths by approximately 6,500 per year.

The Children's Environmental Health Protection Act (Senate Bill 25), passed by the state legislature in 1999, requires the ARB, 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." As a result of the review requirement, the ARB today adopted the new PM standards: 

• The annual-average standard for PM10 is lowered from 30 micrograms per cubic meter (µg/m³) to 20 µg/m³, not to be exceeded.

   

• A new annual-average standard is established for PM 2.5 at 12 µg/m³, not to be exceeded.

   

• Retained the 24-hour average standard of 50 µg/m³ for PM10.

   

• Also retained the 24-hour average standard for sulfates at 25 µg/m³.

The potential health impacts from exposure to particulate matter are significant, especially to sensitive populations. The health effects associated with PM exposure include: premature mortality, increased hospital admissions for cardiopulmonary causes, acute and chronic bronchitis, asthma attacks and emergency room visits, respiratory symptoms, and days with some restriction in activity. As directed by the Children's Environmental Health Protection Act, the ARB will be reviewing all air quality standards to assure the protection of infants and children's health.

The new standards amount to new clean air goals for the state. The standards will go into effect late this year or early next year, after going through California's review process for new regulations.