I think PM10 rates are in similar orders of magnitude, in the "micrograms per cubic meter" range, so i don't think it would be that different. Maybe an order of magnitude larger, but not much more.
I agree, this is very surprising. Before I saw LeifCarrotson's calculation, I would have thought "tons" was the right unit as well. There's so much polluted air, you'd think that it would add up to some significant amount of matter, but apparently not.