ection 109 of the Federal Clean Air Act requires the administrator of the EPA to set national ambient air quality standards (NAAQS) for air pollutants. The section instructs the EPA to set NAAQS at levels to "protect the public health" with an "adequate margin of safety." Pursuant to Sec. 109, the EPA issued new standards for ozone and particulate matter emitted from the operation of trucks.

The American Trucking Association (ATA) sued the EPA, arguing the EPA should consider the cost caused to trucking firms before issuing the NAAQS. The EPA argued that it did not have to do so under the statute. At trial, the U.S. District Court found for the ATA, but the Court of Appeals held for the EPA on the issue.

Section 109 instructs the EPA to set primary ambient air quality standards, "the attainment and maintenance of which are requisite to protect public health" with an "adequate margin of safety".

This text does not permit the EPA to consider costs in setting the standards. The EPA is to identify the maximum airborne concentration of a pollutant that the public health can tolerate, decrease the concentration to provide an adequate margin of safety, and set the standard at that level. Nowhere are the costs of achieving that standard made part of that initial calculation.

ATA states that more factors than air pollution affect public health. They state that "the economic cost of implementing a very stringent standard might produce losses sufficient to offset the health gains achieved in cleaning the air, for example, industries will be closed down, thereby impoverishing the workers and consumers dependent upon those industries.

The case is now before the Supreme Court. If you were a justice, how would you vote? And why?