Presentation description

Salt Lake City experiences Persistent Cold-Air Pools (PCAPs) in the winter months, leading to elevated levels of CO2, PM2.5, and other pollutants in the valley. PCAPs occur when high atmospheric stability, synoptic-scale high-pressure ridges, and reduced surface temperatures inhibit vertical mixing. With the 2034 Winter Olympics Games approaching, understanding how PCAPs affect CO2 enhancements (ΔCO2) and traffic, and their relationship, is crucial. High CO2 levels often indicate other pollutants, so this knowledge can help mitigate air quality issues during large events. Additionally, evaluating the impact of the 2002 WOG on these variables can provide insights into how similar future events might affect local air quality and traffic patterns. We compared the diurnal patterns of ΔCO2 and traffic during the 2002 WOG to those of a typical winter day. This comparison accounts for differences between weekdays and weekends, as well as PCAP and non-PCAP days, as they have distinct patterns in both traffic and ΔCO2. On PCAP days, traffic tends to be slightly reduced, suggesting that societal behaviors are influenced by higher pollution levels and the associated health risks. During the 2002 WOG, traffic was significantly reduced on Foothill Dr since classes were suspended. However, ΔCO2 was higher than average, showing that the WOG likely had other sources of pollution and a more stable boundary layer. Observing ΔCO2 and traffic variations at different WOG events revealed their impacts on traffic and pollution. PCAP days exhibit higher ΔCO2 levels, particularly in the morning when compared to non-PCAP days. Afternoon dips in ΔCO2 levels happen later during the day than on non-PCAP days as more vertical mixing is required to break the capping inversion and reduce ΔCO2. The stable boundary layer on PCAP days accumulates pollutants, reducing the correlation between ΔCO2 and traffic compared to non-PCAP days. ΔCO2 correlates more with State Street and 700E traffic than Foothill Drive, likely due to the University of Utah CO2 measurement location being downwind of downtown.