In this Jan. 5, 2013 photo, an inversion cloud partially obscures shrouds the cities in the northern Wasatch Front from the Snowbasin ski resort boundary in Utah. 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/Standard-Examiner, Robert Johnson)
