It only sucks in February and parts of November. Most of the year it's totally fine. Most days are green, with a handful of red and yellow throughout the year, and most of the red days are from Cali and Nevada wildfires.
I grew up near Seattle, and I regular visit family there. We visit Cali (LA) almost every year too (my in-laws), and I visit family in Montana as well. My in-laws almost always have crappier air than us because smog in LA is a constant, instead of inversion-based like it is in Utah.
And yeah, I wish they air was better. We're doing something to fix it, with tier 3 gas at most stations (lower particulate emissions), lots of people moving to solar power (net metering), and EV charging stations getting more and more available. I wish we'd do more (e.g. tax big trucks like crazy), but air quality is rarely an issue.
That said, I'm acutely aware of air quality issues here because I used to commute almost every day by bike. It's worse near SLC, which is part of why I'm in northern Utah county (close-ish to downtown, but less pollution).