It's not really about the environment in CA. It's about money.
Used to live in Riverside (home of the Bro Life. lol) Case in point, my Pop's '73 CJ-5 had to be smog checked before the rolling exemption year hit it (this is about ten years ago I think) and we have a 401 AMC V8 underhood. Had an edelbrock manifold, holly 650 quad, etc. on it. When run thru the test, it passed with flying colors on emissions, yet failed on visual. My pops had a Ref. leter signed excluding the parts on it, but the station refused to accept it and called in their own ref, who denied it, and told him he had to put the stock manifold and carb on it.
So we find some stock parts, buy them, put them on, and re-test. Passes visual, runs damn near failing on the emissions (way dirtier than with the other parts.) and gets passed.
I love NM. no smog testing except for Bernallillo county. I used to be a certified inspector there, and the test was pretty easy to pass even there. Nothing like CA.