I live less than 20 miles downwind from East Palestine. In the immediate aftermath local subs were full of panic posts about "omg death cloud, look at PurpleAir!".

Turns out it just got cold, and people burned wood. Happens frequently with the Cracker Plant as well, people try to correlate PurpleAir with it, it's always wood burners.

You're using the sensors right. It should be more of general guidance, leave the actual testing to scientists. Like, I wouldn't walk into a hazmat scene with my air purifier if it's sensor was green.