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Francisco Kjolseth | The Salt Lake Tribune A sizable source of emissions come from tailpipes, and idling and "warming up" Francisco Kjolseth | The Salt Lake Tribune A sizable source of emissions come from tailpipes, and idling and "warming up" Francisco Kjolseth | The Salt Lake Tribune A sizable source of emissions come from idling tailpipes as drivers line up for their m Francisco Kjolseth | The Salt Lake Tribune A sizable source of emissions come from tailpipes, and idling and "warming up" Francisco Kjolseth | The Salt Lake Tribune A sizable source of emissions come from idling tailpipes as drivers line up for their m Francisco Kjolseth | The Salt Lake Tribune Pool air quality blankets the valley, obscuring visibility and increasing health concer Francisco Kjolseth | The Salt Lake Tribune Pool air quality blankets the valley, obscuring visibility and increasing health concer Francisco Kjolseth | The Salt Lake Tribune Pool air quality blankets the valley, obscuring visibility and increasing health concer Francisco Kjolseth | The Salt Lake Tribune A sizable source of emissions come from idling tailpipes as drivers line up for their m Francisco Kjolseth | The Salt Lake Tribune A sizable source of emissions come from tailpipes, and idling and "warming up"