Medical breakthroughs are not the only reason Americans are living longer today than they were 20 years ago. Another factor is the air we are breathing in is cleaner.
A study from Harvard and Brigham Young analyzed pollution levels from 51 cities over the past 20 years, and compared it to life expectancy in those cities. They found that Americans are living about 2.5 years longer now than in the 1980's. They believe that is due to tighter air pollution standards that went into effect 12 years ago.