Support WBUREPA Science Panel Considering Guidelines That Upend Basic Air Pollution SciencePlay03:38Download AudioRebecca HersherMarch 28, 2019 ShareSmog fills Utah's Salt Lake Valley in January 2017. Winter weather in the area often traps air pollution that is bad for public health. (Getty Images)
Smog fills Utah's Salt Lake Valley in January 2017. Winter weather in the area often traps air pollution that is bad for public health. (Getty Images)