Speaking of man made climate - I live in one of the smoggier parts of a smoggy area - Southern California. It comes and goes. Some years are better - some are worse. Overall - it is improving here.
I thought I'd seen some pretty heavy smog here, over the years, but I got a wake-up call to REAL Super Smog when I spent a week in Beijing! It was terrible! Every day was worse than anything I had experienced here - even on our very worst days! It was eye burning, nose stopping and running, and contained a heavy unpleasant odor. I tried not to breath deeply, as I did not want all that junk down deep in my lungs. Felt like a 5 pack a day smoker! Other than the bad air - the city is great.
I would not return there without a gas mask.
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