S18: Landmarks of Air Pollution Epidemiology: Legacy of Douglas Dockery, Beatrix Theater, August 27, 2019, 1:30 PM - 3:00 PM

Twenty-six years ago, Doug Dockery and colleagues introduced the world to the Harvard Six Cities Study. Their landmark publication showed strong evidence that people in dirtier cities were dying faster than people in clean cities and the mortality risk was strongly associated with fine particle (PM2.5) emissions. In 2006, continued follow-up showed that the associations persisted, and that life expectancy increased in cities that had cleaned up over time. The Six Cities Study motivated the intensive study of the long-term effects of air pollution in numerous populations all over the world, and the overwhelming weight of the evidence supported the findings of the original study. The original findings in the Six Cities was used by the US Environmental Protection Agency as the foundation for the first Clean Air Act regulations on PM2.5 in 1997. The continued follow-up was one of many studies motivating the lowering of the standards in 2012. The 1997 regulations set off protests from industries affected by the standards, leading to extensive efforts trying to disprove the science and discredit the EPA. Doug was forced to hand over all of the Six Cities data to a third party for reanalysis. The reanalysis unequivocally confirmed the original findings; however, to this day efforts trying to discredit the findings persist. Regardless, there is concrete evidence that the benefits of air pollution regulation far outweigh the costs. In 2009, Doug and colleagues examined changes in life expectancy and changes in PM2.5 in 211 counties in the US 1980-2000. They found that average life expectancy had increased by ~2.7 years and that declining PM2.5 was likely responsible for ~0.8 years of that increase. Doug’s work has led to a new agenda for air pollution research, new air quality standards, improved air quality, and evidence of the benefits of cleaner air.