Associated Press: A thick layer of smog stubbornly lingering over parts of Utah has fouled the state’s air so badly this week that health officials warned people not to exercise outside and some schools kept children inside for recess and sports. The haze that has obscured Utah’s picture-perfect mountain views for the last several days is blamed on a weather phenomenon called an inversion that pins pollution to the valley floors and doesn’t relent until a major storm blows through. The smog …