Wednesday, July 15, 2009

Reflections on History of Particulate Air Quality Standards

BrooklynDodger(s) comment: This seems an important review of the evolution of scientific knowledge and public health intervention. Dockery and his work were in the center of the dispute. The Dodger(s) reading of the history is that the epidemiologic evidence emerged in the published literature around 1995 and later, and that toxicologic evidence emerged within the time frame that the new NAAQS limit for PM2.5 was proposed. The NAAQS limits for PM2.5 then proposed of 15 ug/m^3 annual and 65 ug 24-hour were not fully protective and were roughly equivalent to the old PM10 limits. The 2006 NAAQS of 35 ug for 24 hours was the first true reduction in allowable exposure.

Annals of Epidemiology, Volume 19, Issue 4, Pages 257-263
Health Effects of Particulate Air Pollution

Douglas W. Dockery ScD, a,
aDepartments of Environmental Health and Epidemiology, Harvard School of Public Health, Boston, MA

In the 1980's it was generally felt that particulate air pollution concentrations in the United States were not a hazard to the public health. However, in the early 1990's the application of econometric time-series studies and prospective cohort studies suggested increased mortality associated with acute (daily) and chronic (decades) exposures to particulate air pollution commonly observed in the developed world. The epidemiologic evidence was not supported by evidence of causal associations from other disciplines. Nevertheless, the EPA moved to tighten controls on fine particulate air pollution. The debate over the science was played out in public hearings and the courts. The experience provides lessons on the use of epidemiologic data in setting public policy.

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