The EPA’s Implausible Return on its Fine Particulate Standard

los angeles smog

by Susan E. Dudley, Director

April 10, 2013

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Last January 14th, the Environmental Protection Agency published a final rule in the Federal Register updating the National Ambient Air Quality Standards (NAAQS) for particulate matter. The rule reduces by 20 percent the allowable annual concentrations of fine particles less than 2.5 micrometers in size (PM2.5), from the current 15.0 micrograms per cubic meter (μg/m3) that was affirmed in 2006, to 12.0 μg/m3. 

According to the EPA, meeting the standard “will provide health benefits worth an estimated $4 billion to $9.1 billion per year in 2020—a return of $12 to $171 for every dollar invested in pollution reduction.” This is such an impressive return on investment that it raises the question why the EPA chose a standard of 12.0 μg/m3 when, by its logic, a tighter standard would yield even greater returns.

The Clean Air Act directs the EPA administrator to set standards “requisite to protect the public health…, allowing an adequate margin of safety.” The U.S. Supreme Court has confirmed the EPA’s interpretation that this statutory language precludes consideration of any impacts other than direct health effects from pollutant exposure. Thus, the EPA administrator cannot consider the costs of meeting the standard in determining what levels are “requisite to protect public health” with an “adequate margin of safety.”

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