Salt Lake County PM 2.5 levels (IMAGE) University of Utah Caption Mean 10-min PM 2.5 levels for each 48-hour scenario at the Salt Lake County schools during a clean, moderate winter persistent air pool (PCAP, inversion) and major PCAP event. The bigger the blue dot, the higher the concentration of PM 2.5 particles. In all three scenarios, the lowest PM 2.5 concentrations were on the south and east side of the study area along the bench where elevation ascends from the valley floor. Credit Mullen et. al. Enviro Res (2020) Usage Restrictions Non commercial with attribution License Licensed content Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.