A review on the biological, epidemiological, and statistical relevance of COVID-19 paired with air pollution

•Evaluate studies done on the associations between air pollution and the COVID-19 pandemic.•Discuss the major air pollutants that have an influence in the association between Air pollution and the COVID-19 pandemic.•Address biological complications induced by the aforementioned association.•Discuss the epidemiological and statistical significance of Air pollution in the COVID-19 Pandemic.•This review is different in comparison to other reviews as we assess the three major aspects of the relationship between Air pollutants and its effects on the COVID-19 pandemic. This narrative review paper is aimed to critically evaluate recent studies of the associations between air pollution and the outcomes in the COVID-19 pandemic. The main air pollutants we have considered are carbon monoxide (CO), nitrogen dioxide (NO2), ground-level ozone (O3), particulate matter (PM2.5 and PM10), and sulfur dioxide (SO2). We, specifically, evaluated the influences of these pollutants, both individually and collaboratively, across various geographic areas and exposure windows. We further reviewed the proposed biological mechanisms underlying the association between air pollution and COVID-19. Ultimately, we aim to inform policy and public health practice regarding the implications of COVID-19 and air pollution.