[tokenadult]

I live upwind of Chicago (by prevailing winds) in Minnesota, and we have read in our weather reports that forest fires in Canada have added a lot of particulate matter to our air. The sunsets here have been spectacularly red in recent days. I suppose checking those city-by-city reports of measured pollution for long-term trends and recent spikes might help figure out how unusual Chicago's current conditions are, as you thoughtfully suggest.