Sunday, February 7, 2016

This Inversion Is Going to Be Ugly

Smog in the Salt Lake Valley this afternoon as viewed from the Mt. Olympus Wilderness.  Antelope Island sticking up in the distance.
It's time to get real about the air quality this week.  The system that passed by yesterday, and the strong crest-level winds today, have done essentially nothing to stir up the air in the Salt Lake Valley.  We are now facing a situation where the air quality is already poor as a remarkably strong upper-level ridge builds over northern Utah.  With snow on the ground, this is essentially a worst-case scenario for air quality in February and it needs to be treated as such.

How bad is the air qualty?  Well if you wanted to know this afternoon and had to rely on the Utah Division of Air Qualty, the answer is unclear.  Here's what I got when I tried to go to their web site this afternoon. 

This is simply unacceptable, because the air quality is indeed poor this afternoon.  We know because the University of Utah operates a PM2.5 sampler at the Neil Armstrong Academy in West Valley City and it shows PM2.5 concentrations near or above 35 ug/m3.  That puts it into the unhealthy for sensitive groups category.

The graphs above show that the PM2.5 climbed quite dramatically today, more than we typically see.  I'm not sure if that might be due to photochemistry or perhaps an especially dirty airmass over the Great Salt Lake (there was a bump when the flow switched to west).

The situation is only going to worsen from here.  We will be in the grips of the upper-level ridge through at least Friday.  After that, we'll have to see.  There are some weaker systems being advertised as perhaps influencing things next weekend, but it's too far out to say how things will evolve.

The bottom line is that this is a very serious situation in which we will see poor air quality for several days.  

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