It seems obvious that people who breathe filthy air would die young. Yet people in Shanghai live 13 years longer than those in poor provinces (source), which are presumably less densely populated and therefore might have cleaner air (but maybe they are breathing indoor smoke from coal used to heat?).
Another possibility is that people in Shanghai are being slowly killed by air pollution, but they’re so smart that their high IQ gives them a longer life expectancy to begin with. (Scientific American) Without the massive welfare state that the U.S. operates, it is tough for a person without a high IQ to move to Shanghai and thrive there (apartments are comparable in price to the most expensive U.S. cities; see Forbes).
There is supposedly a five-year difference in life expectancy in north versus south China due to worse air pollution from heating with coal in the north (source). But, again, how to square that with the 13-year boost in life expectancy in Shanghai, a city that is spectacularly polluted.
Mist or filth?