Accumulation post dispersion is also a thing. If the combined effects of individually harmless activities was not an issue, this comment thread wouldn't exist.
I won’t fact check this, but the Bay Area Spare the Air page says the following, which seems pretty reasonable. It’s easier to find science on the danger of the particulate smoke, which you don’t seem to object to.
> During the cooler winter months, more than one-third of particulate pollution comes from wood smoke. On some days, in certain areas, wood smoke can account for up to 90 percent of particulate pollution.
> On cold, calm days, wood smoke can become trapped close to the ground by an inversion layer, typically formed when a layer of warm air acts as a lid over a layer of cooler air. Inversions prevent the air below from rising, which causes pollutants to build up.
tpmx|3 years ago
swid|3 years ago
> During the cooler winter months, more than one-third of particulate pollution comes from wood smoke. On some days, in certain areas, wood smoke can account for up to 90 percent of particulate pollution.
> On cold, calm days, wood smoke can become trapped close to the ground by an inversion layer, typically formed when a layer of warm air acts as a lid over a layer of cooler air. Inversions prevent the air below from rising, which causes pollutants to build up.
https://www.sparetheair.org/about/what-is-spare-the-air