Harvard Six Cities study

The study found that people living in the most polluted city (Steubenville) were 26 percent more likely to die than those in the least polluted city (Portage),[7]^[11] suggesting an association between particulate pollution and higher death rates in urban areas: "Although the effects of other, unmeasured risk factors cannot be excluded with certainty, these results suggest that fine-particulate air pollution, or a more complex pollution mixture associated with fine particulate matter, contributes to excess mortality in certain U.S. cities."^[1][12]

Confirmation

The Six Cities study was followed (and its findings effectively confirmed) by a much bigger epidemiological project, generally referred to as the American Cancer Society (ACS) study, which was carried out by three authors of the original study (Pope, Dockery, and Frank E. Speizer) and four other collaborators. The ACS study correlated air pollution data, lifestyle factors, and death records for a sample of 552,138 adults in 151 urban areas followed over a 16-year period and concluded, just as the original had done, that breathing particulate pollution increases a person's risk of death: "Particulate air pollution was associated with cardiopulmonary and lung cancer mortality but not with mortality due to other causes. Increased mortality is associated with sulfate and fine particulate air pollution at levels commonly found in U.S. cities."^[12][13] A variety of similar epidemiological studies have also supported the association between fine particulate pollution and higher mortality.^[6] Crucially, a 2006 paper by Francine Laden and members of the original Harvard team (Frank Speizer and Douglas Dockery) also confirmed the opposite effect: reductions in particulate pollution save lives.^[14]

Impact

Following the publication of the Six Cities and ACS studies, there were new calls for tougher pollution standards in the United States, and The American Lung Association ultimately sued the US Environmental Protection Agency to bring that about.^[6][15] As a result, in 1997, the EPA introduced the National Ambient Air Quality Standards (NAAQS) with new limits on particulates.^[16] This, in turn, prompted pushback from industry groups and various legal challenges, including a request to release data from the original studies for scrutiny by third parties.^[8] Medical confidentiality agreements prevented this, so, as a compromise, the studies were independently re-analyzed by Daniel Krewski, Richard Burnett, and colleagues on behalf of the Health Effects Institute, which used different statistical methods but essentially confirmed the original findings.^[8][17]

The legal challenges were eventually settled by a Supreme Court ruling on February 27, 2001 (Whitman v. American Trucking Associations, S.Ct. No. 99-1257) that unanimously sided with the EPA.^[18][19][20] Since then, largely as a result of the initial Six Cities and ACS studies, and the follow-up research they inspired, air quality standards and guidelines for particulate pollution have been introduced throughout the world - potentially saving many millions of lives.^[4][12] According to air pollution scientist Gary Fuller: "It is hard to overstate the impact of the Six Cities study on global health... the results still offer the best estimate for how much our lives are shortened by the particle pollution that we breathe."^[21]

Proposed EPA "Honest Act"

When then-EPA director, Scott Pruitt, announced his proposed scientific research policy requiring full transparency of all studies that inform public environmental policies, this would have excluded studies, such as the Six Cities studies, because they used confidential data in personal medical reports that could not be made openly available.^[22] Critics of Pruitt's policy traced its roots to the Harvard Six Cities study.^[22] Various iterations of the bill have been supported by American Chemistry Council, an organization that advises DuPont and Monsanto, among others. It has also been supported by Koch Industries, Peabody Energy, and ExxonMobil. According to the American Association for the Advancement of Science, some within the chemical, manufacturing and energy sector did not approve of the clean air regulations that were implemented because of the Six Cities studies, so they are trying to "attack the science underlying the regulation". The "demand for transparency" was in reality a way to "undermine scientific independence." The Honest and Open New E.P.A. Science Treatment Act, which was sponsored by Lamar Smith (R-Texas) provided the basis for Pruitt's plans for transparency in science policy that he announced on The Daily Caller in March 2018.^[22]

References