Assessing Spatiotemporal Variability of PM2.5 Sources in Salt Lake County Utah during Persistent Cold Air Pool Events

Michael Hannigan, Colleen Reid, Daniel Mendoza, Emma Rieves, MiKyla Harjamaki, JONATHAN SILBERSTEIN, University of Colorado at Boulder

     Abstract Number: 179
     Working Group: Urban Aerosols

Abstract
Persistent cold air pools (PCAP), also referred to colloquially as inversions, are responsible for some of the greatest enhancements in air pollution in Utah's Wasatch Front. PCAPs trap warm air beneath a layer of colder air, which results in the accumulation of particulates during the inversion. In Salt Lake County, PCAPs form with the greatest regularity during the wintertime. These meteorological events can continue for a period of up to several weeks, and pollutants may continue to accumulate until large scale meteorological events disperse pollutants accumulated during the inversion.

Previous research has demonstrated that source profiles of fine particulate matter can differ dramatically on local scales. During inversion episodes, limited mixing and transport may produce a differing suite of local and regional sources when compared to non-inversion periods.

Outdoor fine particulate matter (PM2.5) sampling occurred in seven homes across Salt Lake County (SLCo) during inversion season (November-March). Particulate matter source profiles across the seven sampling sites were generated using positive matrix factorization (PMF). PMF generated source profiles were compared during wintertime inversion and non-inversion periods to assess the influence of these climatic events on spatial distribution of fine particulate sources. A combination of statistical, spatial, and machine learning methods were employed to further understand the sources of fine particulates within SLCo and how regional climatic events may alter the dispersion and mixing of particulate sources.