|Looking north over the smog of Utah County. |
Courtesy Jeff Massey.
Online data from the North Provo site operated by the Division of Air Quality show that 24-hour average PM2.5 concentrations reached 104.3 ug/m3 this morning. That is almost 3 times the National Ambient Air Quality Standard.
|Source: Utah Division of Air Quality|
Plotted below is a comparison with our current event (the data for 2012 was not available). Assuming I'm using the data in the archive correctly (this is an important caveat to consider as the data tables on the DAQ web site contain limited information), current readings at the North Provo site are higher than any measured in Utah county since 2000.
We will have to see if this stands up to a more careful analysis, including quality control of the North Provo data, but this does appear to be an exceptional event by recent standards.
Addendum 11:25 AM:
Airnow.gov suggests that North Provo has the highest air quality index (hourly PM2.5) in the US, with Logan a close second.