Strong Evidence of a Small Harm

In American Farm Bureau Federation v. EPA, a consortium of states and environmental groups challenge the EPA's 2006 rule setting a National Ambient Air Quality Standard for fine particulate matter air pollution. EPA Administrator Stephen Johnson made a clean sweep of the medical and scientific communities, rejecting the advice of physicians, an external advisory committee, and internal agency scientists. Consider the two-pronged legal defense offered by the Department of Justice: The science is uncertain. And the agency's decision should receive deference. The evidence that there are significant health impacts of fine particular air pollution below the standard set by EPA is quite strong.