Conversely, Missoula had no unhealthy ozone days, and ranked among the cleanest cities for ozone in the nation, as it has for each year data has been available. Ozone levels increased in most cities nationwide, in large part due to the record-breaking global heat experienced in the three years tracked in the report.

Fresno, California, had the worst air quality in the nation when looking at all three factors.

Last month, a panel of doctors and scientists convened in Missoula to discuss how climate change caused by the burning of fossil fuels is especially unhealthy for children in Montana and will only get worse.

Paul Smith, the director of pediatric pulmonology at Community Medical Center, said climate change is undoubtedly causing wildfires in western Montana to burn more acres, last longer and produce more smoke. That means children’s lungs, which are more vulnerable than those of adults, suffer the most.