Air pollution and mobility in the Mexico City Metropolitan Area, what drives the COVID-19 death toll?

This paper analyzes the relation between air pollution exposure and the number of deaths due to COVID-19 in the Mexico City Metropolitan Area. We test if short- and long-term exposure to air pollution is associated with a higher number of deaths due to the pandemic. Our results show that long-term exposure to particle matter of ten micrometers and smaller are associated with a higher death toll due to the pandemic. Nonetheless, in the short-term, the effect of air pollution on the number of deaths is less pronounced. Once we control for the short-term commonality among municipalities, contemporaneous air pollution exposure is no longer significant. Moreover, we show that the extracted unobservable common factor is highly correlated to mobility. Thus, our results show that mobility seems to be the main driver behind the number of deaths in the short-term. These results are particularly revealing given that the Metropolitan Area did not experience a decrease in air pollution during COVID- 19 inspired lockdowns. Thus, this paper highlights the importance of implementing policies to reduce mobility and air pollution to mitigate health risks due to the pandemic. Mobility constraints can reduce the number of deaths due to COVID-19 in the short-term, while pollution policies can reduce health risks in the long-term.