Emissions requirements in my city (Atlanta) made an impact but the biggest change came from the city switching all the busses from diesel to natural gas. Only then we saw a visible difference. Sure, if every car was catless it would suck but 5 or 600 enthusiast cars would be negligible. There’s at least that many catless cars rolling everyday from theft here. 😂 LA is still bad in my opinion but that’s simply due to its topography. The western fires can be felt here if the wind is blowing the wrong way. I’ve always wondered if you guys have respirators for fire season. I’d definitely die without one there. Still LOVE to visit though.