The Ongoing Clean Air Debate: The Science Behind EPA's Rule on Soot

The Ongoing Clean Air Debate: The Science Behind EPA's Rule on Soot

June 01, 2001

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The Environmental Protection Agency’s 1997 standard for fine particulate matter is perhaps the most controversial environmental rule enacted during the Clinton administration.  Critics both inside and outside the administration raised doubts about the claimed public-health benefits to be derived from this costly new standard, and EPA’s own science advisory committee questioned its scientific support.  Indeed, this rule, along with a concurrent new standard for ozone, drew more opposition than any other in the 30-year history of the Clean Air Act.

Implementation of the fine particulate matter rule has been delayed by litigation, but a recent Supreme Court decision should allow EPA to move forward.  Meanwhile, the research on the health effects of fine particulate matter has continued, including an extensive reanalysis of the two key studies that were heavily relied upon by EPA in promulgating the rule.  The agency has cited this research as vindication of its regulatory agenda and as justification for moving forward with it as soon as possible.

In truth, the evidence has yet to implicate fine particulate matter as a serious public-health threat.  The recent research has only reinforced the original doubts as to the necessity of a new standard.