For nearly 20-years, TRAX light rail trains have shuttled riders up and down the Salt Lake Valley, saving countless car trips and sparing Salt Lake’s air tons of petroleum-based pollutants. But for the past four years the trains have done even more for Utah’s air. Researchers have been sniffing and mapping out where and when different air pollutants are present along the train’s route. University of Utah scientists recently published the findings of this study in the Journal Atmospheric