22. Fort Collins, CO
Fort Collins is next in line on our list of most polluted cities in the US in 2017. It is one of the most polluted cities in the US for this year as it is ranked 46th for 24-hour particle pollution out of 186 metropolitan areas and 158th for annual particle pollution out of 184 metropolitan area. Moreover, there are 141 people that deal with lung cancer and more than 20,000 with adult asthma.
