Monday, November 4, 2013

The New Air Quality Alert System

The January 2013 "Mother of All Inversions" event from Little Cottonwood Canyon
The Salt Lake Tribune reports this morning on a revamping of the Utah air quality index by the Utah Division of Air Quality.  According to the DAQ press release, this revamping consists of two parts:

Part 1: Action alerts named "unrestricted action" (symbol=circle), "voluntary action" (symbol=inverted triangle), and "mandatory action" (symbol=X).

Source: DAQ
Part 2: Health guidance based on the EPA's national standard Air Quality Index.

Source: DAQ
I took a look at the new DAQ web pages this morning and they appear to be an improvement, but otherwise I don't see much difference between this system and the old.  Perhaps the action alert descriptions and symbols are clearer, but I suspect this won't make much of a difference.

There is some discussion in the Salt Lake Tribune article about state air-quality officials using weather forecasts to help them decide when to call for voluntary and mandatory action days.  I believe this has been done in the past.  For example, the DAQ issued a red air-quality action alert (what is now mandatory action) early in last year's "Mother of All Inversions" event (see blog post and trib article).  It would be great if such a proactive and aggressive approach became the de facto standard and was applied to shorter, less intense inversion events.

Of course, that assumes that the declaration of mandatory action leads to behavioral change that actually reduces emissions.  As some of you may have read in the Salt Lake Tribune a couple of months ago, a recent study by Tribby et al. (2013) (may be paywalled to those of you outside the University of Utah) suggests that air quality alerts reduce driving within the city center, but lead to increases at the edge of the metropolitan area.  Part of the reason for this is people driving to the mountains to escape the poor air quality (yours truly guilty as charged).

Nevertheless, I think I'd still take my changes with a more proactive and aggressive system restricting word wood burning and encouraging mass transit.  Beyond that, it's best to make a sacrifice to Ullr and hope for "good" meteorology with regular storms this winter.


  1. Hey, I really like your blog and I read it every day. I must say though, unrestricted "word" burning definitely leads to inversion events. ... See your last paragraph.