The Bush administration loves to talk about the virtues of “sound science,” by which it usually means science that buttresses its own political agenda. But when some truly independent science comes along to threaten that agenda, the administration often ignores or minimizes it. The latest example involves the Environmental Protection Agency’s decision to reject the recommendations of experts inside and outside the government who had urged a significant tightening of federal standards regulating the amount of soot in the air.

At issue were so-called fine particles, tiny specks of soot that are less than one-thirtieth the diameter of a human hair. They penetrate deep into the lungs and circulatory system and have been implicated in tens of thousands of deaths annually from both respiratory and coronary disease. The E.P.A., obliged under the Clean Air Act to set new exposure levels every five years, tightened the daily standard. But it left unchanged the annual standard, which affects chronic exposure and which the medical community regards as more important.

In so doing, the agency rejected the recommendation of its own staff scientists and even that of its Clean Air Scientific Advisory Council, a 22-member group of outside experts that had recommended a significant tightening of the standards. Stephen Johnson, the agency administrator, claimed there was “insufficient evidence” linking health problems to long-term exposure. He added that “wherever the science gave us a clear picture, we took clear action,” noting also that “there was not complete agreement on the standard.”

One wonders how much evidence Mr. Johnson requires, and how “complete” an “agreement” must be before he takes action. A 20-2 vote in favor of stronger standards seems fairly convincing to us; likewise the unanimous plea for stronger standards from mainstream groups like the American Medical Association.