Sickening fog settles over Salt Lake City area - Article Photos 1/8

In this Jan. 9, 2013, photo, an inversion cloud covers downtown Salt Lake City. A group of Utah doctors is declaring a health emergency over the Salt Lake City area's lingering air pollution problem. Utah Physicians for a Healthy Environment planned to deliver a petition Wednesday, Jan. 23, 2013, demanding immediate action by elected officials. (AP Photo/The Deseret News, Ravell Cal)