Linkages Between Air Pollution and the Health Burden from COVID-19: Methodological Challenges and Opportunities

Benmarhnia, Tarik

The COVID-19 pandemic revealed and exacerbated existing social and economic health disparities and actionable epidemiological evidence is needed to identify potential vulnerability factors to help inform targeted responses. In this commentary, methodological challenges and opportunities regarding the links between air pollution and COVID-19 are discussed with a focus on: i) the role of differential exposure to air pollution across populations and explain spatio-temporal variability of the epidemic spread and resultant mortality; ii) the indirect impacts of interventions treated as natural experiments to control COVID-19 person-to-person spread on air pollution and population health. I first discuss the potential mechanisms between exposure to air pollution and COVID-19 and the opportunity to clearly formulate causal questions of interest through the target trial framework. Then, I discuss challenges regarding the use of quasi-experimental designs that capitalize on the differential timing of COVID-19 policies including the selection of control groups and potential violations of the common shock assumption. Finally, I discuss environmental justice implications of this many-headed beast of a crisis.