This prompted an intense backlash from industry groups in the late 1990s, culminating in a Supreme Court case, in what Science magazine termed "the biggest environmental fight of the decade".
[6][7] The Six Cities study was born in the wake of the 1970s energy crisis amid growing concerns that a squeeze on oil supply would lead to greater use of low-quality coal and, therefore, higher mortality from air pollution.
[6] Dockery and colleagues studied a cohort of 8,111 adults living in six American cities "selected as representative of the range of particulate air pollution in the United States": Harriman, Tennessee; Portage, Wisconsin; St Louis, Missouri; Steubenville, Ohio; Topeka, Kansas and Watertown, Massachusetts.
[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] 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.
[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.
[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.