AQMD Urges Tougher Standards for Particulate Pollution

March 3, 2006

The South Coast Air Quality Management District’s Board today urged the U.S. Environmental Protection Agency to significantly strengthen its proposal for new health standards for fine particulate pollution.

“EPA’s current proposal will not adequately protect public health,” said William Burke, Ed.D., Governing Board Chairman of the South Coast Air Quality Management District.  “We think EPA should follow the recommendations of its own expert panel and adopt standards that will provide an adequate margin of safety for our most vulnerable residents.”

AQMD’s Governing Board today directed its staff to submit a formal comment letter to EPA detailing AQMD’s concerns about the proposed air quality standard.

At issue is the degree to which EPA’s Proposed National Ambient Air Quality Standard for Particulate Matter will strengthen – and in some cases drop – health standards for particulates known as  PM10, PM2.5 and PM10-2.5. ( PM10 refers to particles smaller than 10 microns in diameter; PM2.5 to those smaller than 2.5 microns and PM10-2.5 to those in between 10 microns and 2.5 microns in size.  One micron represents one-millionth of one meter.  A human hair is typically about 70 microns in diameter.)

In its comment letter to EPA, AQMD will outline three main areas of concern:

1. The proposal does not follow the recommendation of EPA staff or that of EPA’s Clean Air Scientific Advisory Committee (CASAC).  Numerous studies have linked PM2.5 levels below the current standard to serious adverse health effects, including increased risk of cardiovascular disease and decreased lung function in children.  The U.S. EPA’s own science advisory committee stated that lowering both the 24-hour average and the annual average standards for PM2.5 is necessary to protect public health.  AQMD’s review concluded that only the most health-protective standard should be adopted.
    
2. The proposal establishes for the first time a national standard that treats urban and rural areas differently.  Review of health studies support a new federal standard for coarse particles in the PM10-PM2.5 range, although little information is known about the toxicity of specific components of this particle size.  EPA’s proposal would exempt areas where wind-blown dust, and agriculture and mining sources, are the predominant components of the particulate mix.  Even in areas where the standard applies, these sources would be exempt from controls to meet the standard.  Studies conducted in the Coachella Valley area of Riverside County have shown adverse health effects from coarse PM.  This area is heavily impacted by sources of coarse PM that would be excluded in EPA’s proposed new standard.
    
3. The proposal establishes criteria for air monitoring sites that would not provide adequate information to assess health impacts in rural areas.  AQMD opposes EPA’s proposal to place monitors in areas that would exclude measurement of re-suspended particulate matter from agricultural and mining sources.  While EPA claims there is insufficient health data to continue such monitoring, EPA’s proposal would only perpetuate the lack of information in this area.

The following table summarizes the current federal PM standards, EPA’s proposal and AQMD recommendations.

Current/Proposed/Recommended PM Standards

* Excludes areas impacted by windblown dust, as well as agriculture and mining

Particulate matter is a complex mix of microscopic particles from myriad sources including diesel soot, tire dust, soil and condensation of combustion gases.  When inhaled, fine particles are readily trapped deep in lung tissues and even transferred to the blood stream.  They have emerged as one of the greatest health threats from air pollution and are associated with a wide range of health effects from increased hospital visits to exacerbation of respiratory diseases including asthma, and premature deaths.

Although the Southland is close to complying with the federal PM10 standard, the area continues to have the highest PM2.5 levels in the nation.  EPA must finalize new PM standards by Sept. 27 as a result of a lawsuit by environmental groups and a subsequent court-ordered consent decree.

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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