[dredmorbius]

What are the other major sources of air pollution / particulate pollution in the Bay Area?

There's no coal consumption to speak of. There's diesel fuel consumption, though that is largely concentrated on transport corridors (I-80, I-580, US-101).

Wildfire emissions all but certainly swamp woodstove usage.

That said, yes, a small number of poorly-tuned fireplaces can create a large amount of smoke. Where the intent is actual useful heating, and not fireplace-as-decoration, thats' a solvable problem.

[s0rce]

See here for the other sources: https://www.baaqmd.gov/~/media/files/communications-and-outr...

Look on page 7

39% Wood Smoke 12 Cooking 12 Other Mobile Sources 12 Road Dust 7 On-Road Motor Vehicles 6 Combustion: Stationary Sources 5 Industrial/Commercial Processes 3 Construction and Farming Dust 2 Animal Waste 1 Wind-Blown Dust 1 Wildfires

Wildfires are basically non-existent in the winter, although the Colorado fire currently doesn't bode well for future California winters.