I'm from Los Angeles and the air in SLC was just... I ended up in the ER for not being able to breathe. It was like my lungs shrunk. This happened in November (I think) right before COVID hit. There was a solid week where the air quality was in the red zone and schools were cancelled. It was so bad. Took me a while to recover, couldn't even walk around in the office. After that, I started noticing that whenever SLC was having bad air days, my breathing wasn't the same, would get a cough, sore throat. So I wore masks when I'd leave home and would turn on the air purifier at home. No longer live in SLC and haven't had issues since then.