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It's probably a lot due to the California fires. Last November we had the worst air quality I've seen since I moved here in 93.

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This would seem to be consistent with the presented data; the bulk of the increase is in the West and Midwest (which I believe picked up a fair amount of the smoke from the fires). The Northeast and South are mostly the same.

The article suggests increases in driving as a contributing factor; but does not explain why that would be concentrated in the West and Midwest, and not the South or Northeast. Likewise with EPA regulation changes: why would they dominate in the West and Midwest? There may be reasons, it's unfortunate the article doesn't explore them.

Midwest here, we got some weird cold grey, but not cloudy weather during the 2018 California fires. It was noticable, both visually and in the air quality.

Yes I agree and feel the whole article is skewed by averaging.

West Coast and Midwest rose by ~10 percent while East Coast and the South is still falling by almost 1 percent.

I wonder how much particulate matter is coming across the Pacific from Asia in addition to the fires causing a raise.

I also question how we could have dropped to Zero particulate matter. That seems wrong to me.

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