Science Panel Challenges EPA

A science advisory committee is challenging the Environmental Protection Agency's decision to tighten the air quality standard for particulate matter, saying the proposal falls far short of what is necessary to protect public health from microscopic soot particles produced by burning fuel in vehicles, power plants, and factories.

During a Feb. 3 teleconference, Rogene Henderson, chair of the Clean Air Scientific Advisory Committee (CASAC), said the panel would draft a letter to EPA Administrator Stephen L. Johnson reiterating and clarifying its recommendation that the agency tighten the standard limiting long-term exposure to fine particles, those less than 2.5 mm in diameter.

Henderson, senior biochemist and toxicologist at the Lovelace Respiratory Research Institute in Albuquerque, acknowledged, "We are in uncharted waters here since this is the first time that CASAC has replied to an administrator's proposed ruling."

In May 2005, the 22-member advisory committee comprising scientists, academics, and state air regulators recommended that EPA tighten the standards for both short-term and long-term exposure to fine particles.

But on Dec. 20, the agency proposed lowering the standard for a 24-hour period from 65 µg/m³ to 35 µg/m³, while leaving the existing annual standard unchanged at 15 µg/m³.

CASAC had recommended tightening the annual standard to either 13 or 14 µg/m³ and setting the 24-hour standard between 30 and 35 µg/m³.

William Wehrum, EPA acting assistant administrator for the Office of Air & Radiation, stressed during the teleconference that the agency had based its policy judgments on the best available science and had examined thousands of new studies on particle pollution as part of its review. EPA is under a court order to issue a final particulate matter standard by Sept. 27.