|The only negative thing about winters in Salt Lake City is the temperature inversion that traps all the smog in the valley.|
Here is how the National Weather Service describes it.
Those wonderful Wasatch mountains surrounding the valley only exacerbate the problem.
When driving along I215 on the Eastern bench of the valley you are almost above most of the muck.
Luckily a storm came through and cleared out all of the stifling yuck - even though it was building back up again the next day.
Here are a couple of pictures to illustrate this 'wonderful' weather phenomenon. The first one was taken last February and you can see across the whole city to the Ochre Mountains. They were taken in almost the same location (University of Utah Medical Center). If you look really close, you can just make out the temple.