I've lived in SF since 1972 and have pretty much always known about Asian smog. And while it's rarely talked about, 29% of San Francisco's pollution comes from

I've lived in SF since 1972 and have pretty much always known about Asian smog. And while it's rarely talked about, 29% of San Francisco's pollution comes from Asia [1]. I don't know about ships, but I assume they contribute significantly as well. I did notice a massive increase in smog during the height of the pandemic from all the ships anchored in the bay, so there is that. [1] https://pubs.acs.org/doi/abs/10.1021/es101450t#afn2 https://pubs.acs.org/doi/abs/10.1021/es101450t#afn2