[woodruffw]

That is indeed very surprising!

My understanding is that here in NYC the single largest (non-industrial?) source of air pollution is heating oil. The city banned the two worst heating oils back in 2015, but with a long phase-out period[1]. I would have expected the situation to be the same in most other cities, although SF's weather certainly doesn't justify oil burning the way NYC's does :-)

[1]: https://www.ny-engineers.com/blog/how-nyc-is-phasing-out-hea...

[s0rce]

I'm not sure how much heating oil use there is in California, seemed like most people without natural gas use either wood or propane.