This whole clean air thing is a crock. Our ancestors in England, Europe or where ever spent their darkness hours in smoky huts with only a hole in the roof as a chimney. A bit over a 100 years ago cities like London had "fog" that was mostly coal and wood smoke, plus all the dirt of having horses and oxen as the prime movers.
The point is, mankind has lived for thousands of years around more polluted air than today and survived to the point there are almost 4 billion of people. The air today in the USA is almost as pure as air in an Intel chip fab clean room.
And their life expectancy was 45 years. Yeah - what a great life that was.