Pandemic-induced changes in traffic patterns and localized air quality in inland Southern California

Abstract:

Because of high population density, various sources of emissions coupled with topography, and atmospheric conditions in the South Coast Air Basin (California), this region historically experiences the worst air quality in the United States. Poor air quality of the region combined with minorities and underserved communities being disproportionally exposed to pollutants makes health conditions much worse for this susceptible part of society. While governmental agencies are doing extensive research to find out the most effective scenario to improve human exposure to pollutants, lockdowns due to COVID-19 presented an opportunity to investigate the relationship between air quality, meteorology, and emissions to design regulatory plans. Lockdown orders to prevent the spread of COVID-19 led to traffic volume reduction of more than 50% on some California highways. In this work, we quantify the changes in traffic due to COVID-19 lockdowns to estimate traffic-related emissions (CO, NO2, PM_2.5) precisely at corridor level in the cities of Riverside and San Bernardino, CA. By aggregating traffic-related emissions at census tract level, we relate localized air quality to localized transportation emissions and disproportionate impacts on environmental justice communities using GIS spatial clustering and joins. Results are provided for the 2020 pre-COVID-19 period and phases 1-3 of government reopenings.