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In response to the COVID-19 pandemic, governments have implemented policies to curb the spread of the novel virus. Little is known about how these policies impact various groups in society. This paper explores the relationship between social distancing policies, traffic volumes and air quality and how they impact various socioeconomic groups. This study aims to understand how disparate communities respond to Stay-at-Home Orders and other social distancing policies to understand how human behavior in response to policy may play a part in the prevalence of COVID-19 positive cases. We collected data on traffic density, air quality, socio-economic status, and positive cases rates of COVID-19 for each zip code of Salt Lake County, Utah (USA) between February 17 and June 12, 2020. We studied the impact of social distancing policies across three periods of policy implementation. We found that wealthier and whiter zip codes experienced a greater reduction in traffic and air pollution during the Stay-at-Home period. However, air quality did not necessarily follow traffic volumes in every case due to the complexity of interactions between emissions and meteorology. We also found a strong relationship between lower socioeconomic status and positive COVID-19 rates. This study provides initial evidence for social distancing's effectiveness in limiting the spread of COVID-19, while providing insight into how socioeconomic status has compounded vulnerability during this crisis. Behavior restrictions disproportionately benefit whiter and wealthier communities both through protection from spread of COVID-19 and reduction in air pollution. Such findings may be further compounded by the impacts of air pollution, which likely exacerbate COVID-19 transmission and mortality rates. Policy makers need to consider adapting social distancing policies to maximize equity in health protection., Comment: 34 pages, 7 figures, 2 tables

Residents near the Great Salt Lake in northern Utah, USA have been exposed to ozone levels during recent summers exceeding the current United States National Ambient Air Quality Standard. Accurately forecasting those exceedances has been difficult as a result of the complex meteorological and photochemical processes fostering them. To help improve such forecasts, a low-cost field study was conducted during summer 2015 to provide comprehensive observations of boundary-layer ozone concentrations in the context of the prevailing meteorological conditions. A network of surface ozone sensors was supplemented by sensors mounted on vehicles, a public transit light-rail car, news helicopter, tethered sonde, and unmanned aerial vehicle. The temporal and spatial evolution of boundary-layer ozone concentrations were compared with the prevailing regional and local meteorological conditions on the basis of gridded operational analyses, surface weather stations, and additional sensors deployed for the field study. High ozone concentrations during June 2015 resulted primarily from local processes while smoke transported from distant wildfires contributed to elevated ozone concentrations during August. The Great Salt Lake influenced ozone concentrations along the Wasatch Front through several mechanisms, most importantly its impact on local wind circulations. The highest ozone concentrations were often found in a narrow zone between the Great Salt Lake and the urban regions to its south and east. Observations from multiple fixed site and mobile platforms during 18–19 August illustrate the complex variations in ozone concentrations as a function of elevation at the surface as well as vertically through the deep boundary layer.

Poster presented at the 17th GHRSST science meeting (XVII), Washington DC, USA, June 6 - 10, 2016. &nbsp

Numerical studies of sea and lake breezes are reviewed and gaps in our current understanding of these thermally-driven circulations are discussed. A numerical sensitivity study is conducted using large-eddy simulations to determine the dependence of sea- and lake-breeze speed and length scales to variations in the land-surface sensible heat flux, offshore background wind, initial atmospheric stability, and lake diameter. This study is the first to test the dependence of sea- and lake-breeze characteristics to variations in these geophysical variables using a three-dimensional large-eddy simulation capable of explicitly resolving boundary-layer turbulence and vertical motion near the sea-breeze front. This study provides new understanding on the sensitivity of sea and lake breezes to variations in the land-surface sensible heat flux, opposing background wind, and lake diameter as well as the complex interactions that occur among these geophysical variables. For the first time, the daytime life cycle of sea and lake breezes in the presence of variations in these variables is simulated, in contrast to many earlier studies that focused primarily on the mature midafternoon sea-breeze circulation. Significant spatial variability in the intensity and vertical structure of lake and sea breezes is noted in the large-eddy simulations. The critical value of an opposing wind at which a sea or lake breeze is destroyed by synoptic-scale pressure gradients is approximately 20% lower in this study than that documented in earlier numerical studies. The depth of sea and lake breezes has also been found to be highly sensitive to the magnitude of the opposing background wind. Finally, the results of this study show that lake breezes for small and medium-sized lakes evolve much differently than sea breezes during the afternoon due to a limited quantity of cool air over the lake.