A cautionary tale on the use of scientific data.

Lamar Smith (R-TX), chairman of the House Committee on Science, Space and Technology, issued a widely publicized letter stating his concern that the Environmental Protection Agency (EPA) uses scientifically discredited and secret data on the health impacts of ozone and particulate matter to justify its emissions restrictions, which force billions of dollars in compliance costs. He has called on EPA to release the data from the Harvard Six Cities Study and the American Cancer Society’s (ACS) Cancer Prevention Study. The ACS study of 500,000 people ran from 1982  to 1989. The Harvard study collected data on 8,000 people over 14-16 years starting in the mid-1970s.

On August 1, the House Science Committee issued a subpoena to EPA requiring the data be delivered to the Committee by August 19.

Chairman Smith asserts that EPA did commit to providing the data two year’s ago, but has not yet sent the data, while moving forward on new ozone limits. EPA’s position is that the data includes health information about individuals who were assured of confidentiality when they enrolled in these studies. As an alternative, the Health Effects Institute was granted access to all the data and published its analysis in July 2000.

So, is this a tempest in a teapot or a serious conspiracy to restrict the use of fossil fuels without adequate scientific justification. A few observations on the “facts”:

  • According to Rep. Smith the National Academy of Sciences (NAS) in 2004 found that the data used by EPA is of “little use for decision making”. The 2004 NAS report, Research Priorities for Airborne Particulate Matter: IV, Continuing Research Progress, does use the words quoted above but in a slightly different context. The NAS report observes that additional tracking of the cohort populations used in the two old studies would be of little value because people have moved and air quality has changed over time in the target locations.
  • Rep. Smith stated that the White House Office of Management and Budget found the EPA claims based on its data sets “may be misleading” and should be treated with caution. OMB’s analysis seems more scathing to me. OMB states, “EPA’s estimates of mortality due to PM2.5 exposure are implausibly large when compared against other references.”
  • By way of background, the two old studies did conclude that people living in areas with poor air quality faced higher mortality:  The six-cities study showed that excess mortality risk was about 26% for the city with the highest levels of particles (Steubenville, Oh.) compared to the city with the lowest levels (Portage, Wis.) based on death records for the period 1979-1989. The ACS study found that higher levels of sulfate were associated with higher levels of mortality.

Last 5 posts by Edie Allison

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