2010 April 11: Bureau of National Affairs: EPA Science Advisers Support Stricter Standards for Airborne Fine Particles

2010 April 11: Bureau of National Affairs: EPA Science Advisers Support Stricter Standards for Airborne Fine Particles

By Andrew Childers

Available research into the adverse health effects of airborne fine particles supports the Environmental Protection Agency’s recommendation to significantly strengthen air quality standards for the particles, the agency’s science advisers said April 8.

Though the most recent research into the health effects of particulate matter largely restates conclusions that were available when EPA last reviewed the standards in 2006, that evidence still suggests stricter standards are needed to protect public health, members of the Clean Air Scientific Advisory Committee said in a review of EPA’s Policy Assessment for the Review of the Particulate Matter National Ambient Air Quality Standards: First External Review Draft, which recommends that the agency strengthen the national ambient air quality standards for fine particles.

“I’m not sure there’s a lot of newly available data that wasn’t present five years ago,” CASAC member Frank Speizer, a professor of environmental science at Harvard Medical School, said during the committee meeting, which took place via conference call. “There may be more of it. We need to keep in mind five years ago the administrator essentially ignored what we told him and [EPA] staff told him was there.”

Both the primary and secondary air standards for fine particles are 15 micrograms per cubic meter (µg/m3), averaged annually, and 35 µg/m3 averaged over 24 hours. The primary standard is set to protect public health, while the secondary standard protects against impacts on the environment and public welfare such as degraded visibility.

EPA last revised the standards in 2006, tightening the 24-hour standards while leaving the annual standards unchanged. That went against recommendations from CASAC that the annual standards should be strengthened as well, and that existing standards were insufficient to protect public health.

The draft policy assessment, released in March, was prepared by EPA as part of its periodic review of the national ambient air quality standards for particulates. The report said the agency’s existing standards for fine particles are insufficient to protect public health or to reduce the pollutant’s impact on visibility. The draft report recommends that EPA establish significantly more protective standards.

The report also recommends that EPA consider setting a separate secondary air quality standard for fine particles—those 2.5 microns in diameter or smaller—to protect visibility.

Assessment Recommends Tougher Standards

EPA’s draft policy assessment recommends the agency set significantly stronger annual and daily standards for fine particles. The draft policy assessment provides two scenarios for EPA to consider when revising the standards.

The first would revise the annual standard in a range between 12 µg/m3 and 13 µg/m3 while either retaining the existing 24-hour standard of 35 µg/m3 or revising it in a range between 30 µg/m3 and 35 µg/m3.

The second scenario recommends that EPA consider setting the annual standard in a range between 10 µg/m3 and 11 µg/m3, and revise the 24-hour standard to between 25 µg/m3 and 30 µg/m3. The second scenario would “reflect a more precautionary approach,” the draft report said.

Helen Suh, a CASAC member and associate professor of environmental chemistry at Harvard, said EPA’s “rationale is appropriate” for recommending those alternative air standards.

Coarse Particle Review Pending

EPA is also reviewing its air standards for coarse particles—those 10 microns in diameter or smaller but larger than 2.5 microns in diameter. The agency will provide recommendations for any needed revisions to the air standards for coarse particles in the second draft of the policy assessment.

Both the primary and secondary standards for coarse particles are 150 µg/m3, averaged over 24 hours.

EPA’s Policy Assessment for the Review of the Particulate Matter National Ambient Air Quality Standards: First External Review Draft is available at http://www.epa.gov/ttn/naaqs/standards/pm/data/20100308firstdraftpmpa.pdf. That report and other documents related to the review are available at http://www.epa.gov/ttn/naaqs/standards/pm/s_pm_index.html.

 

Copyright © 2010 by The Bureau of National Affairs, Inc., Washington, DC
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