I grew up in Southern California, in the 50's, and remember taking deep breaths, and it would hurt. Thirty years later, the Clean Air Act was passed, and I thought that was great! California would become livable again. Wrong. It's worse now. More cars and trucks, bigger cars (SUV's) and trucks, faster cars and trucks, and smog devices illegally manipulated. The sleepy quiet neighborhoods are disrupted with motorists "racing" through the streets, causing even more pollution.
My solution was to buy a hybrid car (I was one of the first 100 buyers in California), and then switch to an all electric car (I was one of the first 3000 buyers), and install solar panels on my roof (after winning a big battle against my HOA, who initially refused, saying it wasn't "pretty," I'm doing my part for cleaner air). Unfortunately, I moved to the wrong neighborhood and didn't know it. The air pollution around my house is 10 times the legal maximum, set by the EPA, and it seems I'm doomed to have early "dementia," among other complications from excess smog.