It was the suppression of volatile vapors, the smog being photocatalytic hydrocarbons as you point out. Catalytic converters were indeed a big deal, as were the vapor barriers on fuel pumps.
But that witches’ brew of smog was (is) a mixture of all sorts of volatiles from many sources (e.g. paint shops and factories).
There’s by definition no one solution to diffuse fugitive emissions, and I’m glad the various AQMDs and CARB are working on it. I’m also glad they are organized in a decentralized fashion, so that different districts can have different rules and programs.
Oh and the ECUs (and their O2 sensors) came in after a lot of the work had been accomplished back in the carburetor days, but things are a lot cleaner today because they continued.
But that witches’ brew of smog was (is) a mixture of all sorts of volatiles from many sources (e.g. paint shops and factories).
There’s by definition no one solution to diffuse fugitive emissions, and I’m glad the various AQMDs and CARB are working on it. I’m also glad they are organized in a decentralized fashion, so that different districts can have different rules and programs.
Oh and the ECUs (and their O2 sensors) came in after a lot of the work had been accomplished back in the carburetor days, but things are a lot cleaner today because they continued.