A giant step towards cleaner air—and longer lives

Ever since a toxic black cloud dubbed the Great Smog—made up primarily of coal-burning emissions and diesel exhaust—hovered over London in 1952 and killed an estimated 12,000 people within days, environmental scientists had worried about the mysterious ingredients composing industrial haze. In the US, that concern intensified in 1973 following the Arab oil embargo, when power plants were expected to substitute cheap, high-sulfur coal for expensive oil. What could the nasty emissions from dirtier fuel do to people?

It was against this backdrop that HSPH researchers conducted the so-called Six Cities Study, one of the single most influential research projects in public health history. The study—which examined the health effects of air pollution on more than 8,000 adults and 14,000 children over 14 to 16 years—paved the way for the nation’s first-ever Clean Air Act regulations on particulate matter smaller than 2.5 microns in diameter, rules that are by now responsible for adding years to thousands of lives.

These were no ivory tower academics: Led by Professors Frank Speizer and Ben Ferris (a legendary public health figure who died in 1996), the HSPH team was all-in and hands-on. Jack Spengler, now Akira Yamaguchi Professor of Environmental Health and Human Habitation, built the personal air quality monitoring equipment worn by study subjects. Douglas Dockery—now chair of HSPH’s Department of Environmental Health—traveled from city to city, setting up pollution monitors in residents’ homes.

The results were stunning. Residents of Steubenville, Ohio—the city with the dirtiest air among the six studied—were 26 percent more likely to die prematurely than citizens of Portage, Washington, which boasted the cleanest air. Air pollution translated to about a two year loss in life expectancy.

Over the past 30-plus years, the Six Cities Study and subsequent research by the School has had a substantial—and lasting—impact on air quality. It also provides a textbook case of how public health should work: Good science shapes policy. Good policy saves lives. Today, Dockery can look out of his window across the Charles River at the Cambridge skyline and see a view that, decades earlier, was often obscured in haze. “That’s gratifying,” he says.

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