As you have probably noticed, Utah air quality has been the main subject of our recent Smog Blog posts. As Ruben pointed out in his Wednesday post, Utah physicians declared the air quality issue a public emergency and delivered a letter to the Governor's Office offering a list of suggestions in order to reduce pollutants emissions. Today the topic made it to national news both on NBC (video below) and NBC (link here).
If you've been following the news and also our recent posts about Utah air quality you are probably hearing/ reading the expression "temperature inversions" many times. Every winter many places across the globe face this problem. Big cities like Los Angeles, São Paulo (Brazil), Mumbai (India), Mexico City and also small cities like Provo and Salt Lake City in Utah are often the victims of temperature inversion. A very nice explanation of the phenomena can be found here at the National Weather Service page from Salt Lake City. So if after reading it, the concept is still not very clear, I hope I can help you out by showing in this plot two temperature profiles obtained by radiosondes in Salt Lake City. Here you can "see" the temperature inversion in the wintertime profile, comparatively to a summertime temperature profile (in red). See the difference in the slopes, closer to the ground? That's the inversion we're talking about.
According to the Salt Lake Tribune, the weeks-long inversion might finally get a break with the expected rainfall/ snowstorm towards the end of the weekend.
Below is the AIRNow animation from AIRNow zoomed in Salt Lake CIty area (left). Code orange persisted throughout the day and code red was observed in the early evening. In Eastern Utah, purple levels (Very Unhealthy) were also observed (right).
Elsewhere in the US (below), moderate levels were observed in Southeast (most likely due to the large number of fires reported in the region, as Daniel pointed out yesterday), Oklahoma, Midwest and Northeast. In the Western portion of the country, California, Oregon, Washington also experienced mostly moderate levels of PM2.5.