A new study ranks Oklahoma City and Tulsa among the unhealthiest of America's 100 largest cities. Learn more about the ranking.

Due to Canada’s raging wildfires, a thick haze has been cast over major cities triggering air quality alerts across multiple states.This marked New York City as the 7th most polluted ...

Smoke from Canadian wildfires hovered over several Midwestern states Saturday, bringing warnings of unhealthy air ...