I've taken the liberty of adding to the graph a couple of horizontal lines that roughly denote the current 24-h averaged PM2.5 concentrations at the Salt Lake City (54 ug/m3) and North Provo (74.1 ug/m3) based on provisional data available on the Division of Air Quality web site. In accordance with school spirit, Salt Lake is red and North Provo blue.
While this is a bad event in Salt Lake, current PM2.5 levels are not exceptional compared to past events (compare horizontal red line to the green "Hawthorne" line). All but one year during the 10 year period below saw at least one event with higher concentrations.
|Source: DAQ (my horizontal red and blue lines annotated)|
And, adding to the misery, it now appears that Tooele has joined the other Wasatch Front counties with an exceedance of the National Ambient Air Quality Standard.