How "dirty" is the air?

A few people were wondering how bad the air is right now in the Salt Lake Valley.  I know little about health, but we can look a bit at the quasi-real-time particulate matter data that is available on the Utah Division of Air Quality web site.

The National Ambient Air Quality Standard (NAAQS) for a 24-h average PM2.5 concentration is 35 µg/m3. For this location, the 24-h running average remains below 20 µg/m3. 

In major events, we typically flirt with the NAAQS at this location, so we are not approaching the severity of the worst mid-winter inversions.