The group’s annual State of the Air report tracks ozone pollution, commonly known as smog, and fine particle pollution, which can come from wildfire smoke, vehicle exhaust and industrial emissions.
This year, Phoenix ranks fourth in the nation for ozone pollution. Denver comes in eighth, followed by Las Vegas at 11th and Salt Lake City at 13th. Fort Collins (18th), Albuquerque (19th) and Boise (24th) also appear on the list.
Melissa Ramos, senior manager for clean air advocacy with the American Lung Association, said climate change is worsening air quality.
“Extreme heat is a serious issue among Mountain West states, and that essentially drives up a lot of the pollution that we’re seeing,” Ramos said.
Ozone pollution is a persistent problem across the Mountain West, where hotter temperatures help drive those chemical reactions.
Geography can make conditions worse. Many cities in the region sit in valleys or basins, where polluted air can become trapped and linger. Wildfire smoke adds another layer, especially as fires burn longer and more intensely in a hotter, drier climate, Ramos said.
The report shows a more mixed picture for particle pollution. In northern Nevada, the Reno area improved across categories this year and dropped out of the top 25 most polluted cities for fine particle pollution, known as PM2.5.
Ramos said some of that improvement may reflect fewer extreme wildfire years included in this year’s data, and warned progress could be short-lived without further action. Nationwide, more than 4 in 10 people live in areas with at least one failing air quality grade.
Ramos said reducing pollution will require major changes.
“If we can be transitioning away from fossil fuels and investing more in clean energy and clean transportation options, that’s going to reduce a lot of the pollution that we’re seeing,” Ramos said.
This story was produced by the Mountain West News Bureau, a collaboration between KUNR, Wyoming Public Media, Nevada Public Radio, Boise State Public Radio in Idaho, KUNC in Northern Colorado, KANW in New Mexico, Colorado Public Radio, KJZZ in Arizona and NPR, with additional support from affiliate newsrooms across the region. Funding for the Mountain West News Bureau is provided in part by the Corporation for Public Broadcasting and Eric and Wendy Schmidt.
