My grandmother (born in 1900), often spoke of Spring-cleaning in her younger years. The indoor walls were covered with soot from winter pollution. The 1920 Wasatch Front population was 273,775 (29 per square mile).
Automobiles were a luxury item and most people used animals for transportation. The warmth of a fire meant you could live to see a better, cleaner day.
In 2010, the Wasatch Front had a total population of 2,133,909 (228 per square mile). People no longer need to clean off the black soot that covered everything in the '20s. Why? Because, despite having eight times the 1920 population (and pretty much every person above age 16 drives an automobile), we burn much cleaner than we did in the '20s.
It also means that despite having a very rural population in 1920 the inversion wreaked havoc on air quality. We cannot prevent the inversions. Despite the giant growth Utah has experienced, we've cleaned our air.
Government cannot legislate the air quality desired by environmentalists without adverse economic results. Besides, only a massive reduction in population will reduce pollution levels during the inversion season and that is not reasonable.