Sunday, January 6, 2013

Pollution Event in Perspective

Mechanical Engineering Professor Eric Pardyjak pointed out that Division of Air Quality has a graph showing the highest PM2.5 levels by year for 1998–2007.  Although not quite up to date, it allows us to provide some context for the current event.

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)
On the other hand, it appears that the current event features unusually high PM2.5 concentrations at the North Provo observing site (compare horizontal blue line to purple "North Provo" line).  It's a bit tough to see all the trend lines in the graph above, but it appears that current PM2.5 concentrations are at or above those observed during the 1998–1007 period at that or any other site in Utah county.

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.

Source: DAQ

No comments:

Post a Comment