Phoenix has once again earned a failing grade from the American Lung Association in the organization’s annual rankings of air quality across the U.S.
According to this year’s State of the Air report, Phoenix is the fourth-smoggiest city in the U.S. Phoenix had no improvement from last year, when the city also ranked fourth-worst for ozone pollution.
Ozone pollution, or smog, comes from tailpipe emissions, power plants and other industrial sources, but it’s exacerbated by heat and sun…