Health risks of dirty n dangerous air not just evident in increased health problems and deaths as air becomes filthier.
Also evident as air is cleaned, and people benefit, inc by living longer, as risks are reduced. Reuters reporting from US:
Reducing fine particles given off by automobiles, diesel engines, steel mills and coal-fired power plants have added as much as 15 percent of the 2.72 years of extra longevity seen in the United States since the early 1980s, they wrote in the New England Journal of Medicine.
Using life expectancy, economic, demographic and pollution data from 51 metropolitan areas, Pope and his colleagues found when fine-particle air pollution dropped by 10 micrograms per cubic meter, life expectancy rose by 31 weeks.
Areas such a Akron, Ohio, and Philadelphia showed that kind of drop in air pollution.
The bigger the decline, the longer people began living.