Pollution Doesn't Take a Holiday

A truly spectacular airmass pushed into the Salt Lake Valley and gave us a remarkably clear Christmas Eve.  As the sun was setting and Santa approached, one could breath easy for their long winter's nap. 

4:30 PM MST Christmas Eve, 2013

However, it didn't take long for a veil of smog to begin to develop.  On Christmas, air quality was still good, but one could begin to see the effects of all the yule log burning on the visibility over the valley (I'm not sure if wood pollution is the problem, but "yule log burning" seemed to fit well there).  Note in particular the smoggy tint in the right-hand side of the image below.  

4:30 PM MST Christmas

The view from the Avenues Foothills also showed a veil of Christmas smog hanging over the valley on an otherwise unbelievably spectacular day.

A thin veil of Christmas smog over the Salt Lake Valley

The latest observations from the Division of Air Quality shows that the hourly PM2.5 concentrations peaked last night at 33.5 ug/m3 and the 24-h average PM2.5 now sits at about 15 ug/m3.  Although these are only in the moderate air quality category, this case provides an example of just how fast we see our air quality deteriorate after the valley has been flushed out and the inversion builds in.  From good to moderate air quality in 24 hours.  Pollution doesn't take a holiday. 

Source: Utah Division of Air Quality

There is, however, a small Christmas gift on the way.  The inversion will strengthen today and probably reach peak intensity tomorrow.  On Friday night through Saturday morning, the models are calling the ridge to shift just far enough upstream to let a weak front push through Utah.    

Hopefully this will give us at least a partial mix out, if not better.