Air Quality Crisis: Multiple US Regions Among Worst in Nation.

Reno and Las Vegas are among the top 25 most polluted cities in the US for short-term particle pollution and/or ozone levels, according to the American Lung Association's "State of the Air" report. Reno ranked 19th for ozone levels and fifth worst for short-term particle pollution, while Las Vegas improved slightly, moving from 11th to 15th worst. Both Washoe and Clark counties received an "F" grade for ozone pollution and short-term particle pollution. Wildfires were a major contributor to the "unprecedented levels of short-term particle pollution" in Reno and Vegas.