Pollution was way worse in the past. Old pictures of american cities from 50 years ago look like Beijing. We hadn't yet offshored heavy industry by that point and like you said, a larger percent of the metro was living closer to it. And whatever you saw outside was actually better than your air quality inside where these pollutants would accumulate and mix with Dad's cigarette smoke.

This was the air you were breathing back then (1, 2, 3).

1. https://www.washingtonpost.com/wp-apps/imrs.php?src=https://...

2. https://upload.wikimedia.org/wikipedia/commons/0/0a/SKYSCRAP...

3. https://www.saturdayeveningpost.com/wp-content/uploads/satev...