NCPA - National Center for Policy Analysis

Science Behind EPA's Soot Standard Still Questionable

June 25, 2001

The Environmental Protection Agency's 1997 standard for fine particulate matter was perhaps the most controversial environmental rule enacted during the Clinton administration. Implementation of the rule has been delayed by litigation; however, a recent Supreme Court decision should allow EPA to move forward.

Currently, the EPA regulates larger particles of soot (10 microns) released into the air by power plants and now the agency wants to separately regulate fine particulate matter (2.5 microns). 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.

  • The Office of Science and Technology Policy declared the database for levels of PM2.5 was very poor and only a handful of studies actually studied PM2.5 effects.
  • George Wolff, the Clean Air Scientific Committee chair, informed Congress of the lack of scientific support for the PM2.5 standard.
  • The EPA and researchers who conducted the original study of health problems related to fine particulate matter refused all access to the data and denied any chance of an independent review.
  • To the limited extent PM2.5 data was available to other researchers, some concluded that PM2.5 was not shown to be a public-health threat.

Critics say the evidence has yet to implicate fine particulate matter as a serious public-health threat. Recent research has only reinforced the original doubts as to the necessity of a new standard.

Source: Kay Jones and Ben Lieberman, "The Ongoing Clean-Air Debate: The Science Behind EPA's Rule On Soot," June 2001, Competitive Enterprise Institute, 1001 Connecticut Avenue, N.W., Suite 1250, Washington, D.C. 20036, (202) 331-1010.


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