Environmental injustice in California revealed by the COVID-19 economic shutdown

Abstract:

In March 2020, California experienced a sudden, widespread economic shutdown due to public health concerns surrounding the spread of COVID-19. We use an empirical statistical model, with the shutdown as a treatment condition, to quantify the pre-/post- shutdown change in air pollution for different populations throughout CA. We analyze data from state-run stations, privately owned sensors, and satellites, while controlling for temperature, relative humidity, and precipitation. During the shutdown, air pollution improved disproportionately for Hispanic and low-income communities, revealing the environmental injustice that exists during non-shutdown conditions. A 10 percentage point increase in the Hispanic population of a census block group is associated with a 0.77 μg m^-3 reduction in PM2.5 after the shutdown, and a 10% reduction in median income is associated with a 0.34 μg m^-3 reduction in PM2.5. We observe a similar pattern when we use satellite column NO2 measurements as the pollution metric. After incorporating cell phone GPS data, we conclude that pollution reductions in these communities can not be explained by reductions in local mobility, indicating that pollution exposure inequities are largely driven by non-local economic activity. In this study, we use emerging citizen air quality networks and the unprecedented economic conditions to demonstrate the magnitude and location of environmental injustice caused by disproportionate air pollution exposure in CA.