Top Scientist Testifies at House Science Committe Hearing, May 8, 2002
On May 8, 2002, the U.S. House of Representatives Science Committee chaired by Rep. Sherwood Boehlart (R-NY) held a hearing to examine what is known about the impact of small particle air pollution on human health. The hearing was intended to assess the state of scientific knowledge about small particle air pollution and its effects on health and to ask how we should go forward with a research agenda to address outstanding questions. Dr. Joel Schwartz, Associate Professor in the Harvard School of Public Health and the Harvard Medical School, and a leading researcher on the health effects of particulate matter presented some very compelling testimony.
His testimony lays out how recent science has addressed each of the major criticisms that industry made of the science on particulate matter. The criticisms made were:
1. The dozens of studies showing day to day changes in airborne particle (PM) levels were associated with day to day changes in how many people died were flawed, due to inadequate control for weather, season, and other pollutants, or to only reporting results from cities where there was an association;
2. Even if those studies were true the deaths were only of persons who were going to die soon anyway, whose deaths were brought forward by a few days;
3. Even if those studies were true, there was a threshold below which no effects would be seen, and hence the health benefits of reducing pollution levels were low;
4. Even if those associations were true, we did not know which types of particles were associated with these deaths, and could not regulate until we resolved that question;
5. The two prospective studies, which followed groups of people over time, controlled for individual risk factors, and found higher death rates in more polluted cities were flawed, and would not stand up to more rigorous analysis. Because they contained confidential medical records of participants, they were not publicly available for re-analysis, and this was attacked as hiding the data.
6. There were no biologically plausible mechanisms to support the epidemiological associations, or information on who is sensitive.
7. That the associations were implausible because personal exposures to particles were not related to ambient exposures.
In his testimony, Schwartz addressed each of these arguments in turn, citing new scientific studies that debunk these criticisms. The Committee [www.house.gov/science/] offers the Schwartz testimony online.
Additional information on the hearing is available online.
