Chronic exposure to air pollution implications on COVID-19 severity.

Populations in areas with higher levels of air pollution both indoors and outdoors show increased mortality rates when infected with coronavirus disease 2019 (COVID-19). The association between air quality and COVID-19 is commonly attributed to the risk of transmission. Although controlled transmission is crucial, further investigation into air quality traits that contribute to the lethality of COVID-19 in infected persons enables risk stratification and optimization of the allocation of resources. There is a need for a valid basis for the proactive identification of indicators of COVID-19 severity in air quality that allow for the implementation of systematic environmental improvements aimed at preventing COVID-19 mortality. In this paper, chronic exposure to fine particulate matter (PM) is identified as a source of disrupted activation of the hypothalamic-pituitary-adrenal (HPA) axis; it is therefore, a contributable variable to COVID-19 mortality.