Over the past three decades, American life expectancy has increased by more than two and a half years. The majority of that improvement is attributable to the diminishing popularity of smoking and to improved medicine and socioeconomic conditions. But pollution reduction—mostly due to the Clean Air Act—makes a significant contribution.
As Scientific American reports:
A 2009 study published in the New England Journal of Medicine found that efforts to reduce fine particle pollution from automobiles, diesel engines, steel mills and coal-fired power plants have added between four and eight months to the average American’s life expectancy in recent years.\n
Since the seminal environmental law was passed in 1970, levels of all major air pollutants are down. Are we're living longer for it.