I lived in the LA basin for a handful of years commencing in the Fall of 1979. Flew in at night. Awoke the next morning, stepped outside and was immediately cloaked in a thick veil of orangish-brownish-grayish smog. I kid you not: Looking westward from the backyard of my parent's house, a large hillside that was 3/8 of a mile away was indiscernable. It wasn't until 3-4 weeks later on a clear day once I'd formed a sense of the lay of the land that I realized the hill was there. Serious smog. Brass lamps inside the house became pitted after a year or so. Aluminum window frames discolored and oxidized. Paper products left out in the garage turned into brittle, brown fragments. I can only imagine what it did to people's lungs.
For all of their legislative overreach and nanny state shenanigans for which California is famous, they did succeed in clearing up the air in the LA basin. However I'd note that this is the time of year out there when the air is the cleanest and clearest. Check stats immediately after a major Pacific front passes through, and it should be even better. The converse occurs in September.
“They didn’t do shit” The world evolved with less plotting cars, some by mandate, some by innovation.
You would be mistaken. They regulated businesses into oblivion - anything emitting volatile compounds was at first required to be permitted, and then they ratcheted requirements down so hard businesses complied, shuttered or moved. Fireplaces are all but banned. Burn wood in one? Yeah, that might be a death penalty offense. Gas fireplaces may be ok though? Print shops I worked at first started getting scrutiny in the early 80s. Print shops you ask? Lots of volatile organics in use there: Press wash, strippers, deglazing compounds, etc.
So yeah, they did lots of shit - all off it detrimental or costly to businesses. And you can thank these guys for it all.

Don’t reallize. Mainly because I haven’t been to cali since like 1997.
Fuck it into the ocean.