Commentary on the HEI reanalysis of the Harvard Six Cities Study and the American Cancer Society Study of Particulate Air Pollution and Mortality.

The Health Effects Institute, established in 1980, is an independent and unbiased source of information on the health effects of motor vehicle emissions. HEI supports research on all major pollutants, including regulated pollutants (such as carbon monoxide, ozone, nitrogen dioxide, and particulate matter) and unregulated pollutants (such as diesel engine exhaust, methanol, and aldehydes). To date, HEI has supported more than 200 projects at institutions in North America and Europe and has published over 100 research reports. Consistent with its mission to serve as an independent source of information on the health effects of motor vehicle pollutants, the Institute also engages in special review and evaluation activities. Typically, HEI receives half its funds from the US Environmental Protection Agency and half from 28 manufacturers and marketers of motor vehicles and engines in the US. Occasionally, funds from other public and private organizations either support special projects or provide resources for a portion of an HEI study. Regardless of funding sources, HEI exercises complete autonomy in setting its research priorities and in reaching its conclusions. An independent Board of Directors governs HEI. The Institute's Research and Review Committees serve complementary scientific purposes and draw distinguished scientists as members. The results of HEI-funded research and evaluations have been used in public and private decision making. Shape of concentration-response function (with standardized residuals plotted) for cities in the ACS Study. Page 174. Part II. Table 32. After " O 3 (ppb) " in the left column, append footnote b that reads: " b Based on daily 1-hour maximum concentrations. " Page 178. Part II. Table 33. For O 3 (second row from bottom), in the column " Description of Covariate and Source of Data " , the entry should read exactly like the other three: " Daily average concentrations averaged by year for 1980; from residential, commercial, or mobile monitors " Page 259. Health Review Committee's Commentary. Gaseous Copollutants section. The third sentence should read: " For four gaseous copollutants (carbon monoxide, nitrogen dioxide, ozone, and sulfur dioxide), city-specific annual means of daily average concentrations from the year 1980 were obtained from AIRS and used in the reanalysis (see Appendix E, Part II). " At the end of the same paragraph, add this sentence: " For this analysis, the ozone values were based on daily 1-hour maximum concentrations. " Part II, Appendix E (available on request) Page 5. Gaseous Copollutants section. The second …