_______________ Black line is the PM2.5 Non-Attainment Area.

* When calculating Air Quality Index Level on Near-Real-Time Data, the average PM2.5 for a one hour time frame is used. Since the EPA doesn't have index levels for the average one hour time frame, the levels indicated on this web page are calculated as if the one hour average PM2.5 were the peak value in an average 24 hour period with normally distributed emissions.