Hm. I wonder about some of these results. That number for chicago is wild - that would be clearly visible, serious pollution. And my old haunt BKK, which I left specifically because of the awful air, 32!? The city where I would come home from work with a grey shirt that was white when I left is cleaner than zurich? From personal experience in both cities I assure you it is not.
It's anecdotal, I know, but I wonder about some of this data.
It's anecdotal, I know, but I wonder about some of this data.