Environmental Factors Influencing COVID-19 Incidence and Severity

Emerging evidence supports a link between environmental factors- including air pollution and chemical exposures, climate, and the built environment-and severe acute respiratory syndrome coronavirus 2 (SARSCoV-2) transmission and coronavirus disease 2019 (COVID-19) susceptibility and severity. Climate, air pollution, and the built environment have long been recognized to influence viral respiratory infections, and studies have established similar associations with COVID-19 outcomes. More limited evidence links chemical exposures to COVID-19. Environmental factors were found to influence COVID-19 through four major interlinking mechanisms: increased risk of preexisting conditions associated with disease severity; immune system impairment; viral survival and transport; and behaviors that increase viral exposure. Both data and methodologic issues complicate the investigation of these relationships, including reliance on coarse COVID-19 surveillance data; gaps in mechanistic studies; and the predominance of ecological designs. We evaluate the strength of evidence for environment-COVID-19 relationships and discuss environmental actions that might simultaneously address the COVID-19 pandemic, environmental determinants of health, and health disparities.

Automated summary

Emerging evidence suggests that environmental factors, such as air pollution, chemical exposures, climate, and the built environment, are linked to the transmission, susceptibility, and severity of SARS-CoV-2 and COVID-19. These factors have long been known to influence viral respiratory infections, and similar associations have been found with COVID-19 outcomes. While there is more limited evidence regarding chemical exposures, environmental factors were found to affect COVID-19 through various mechanisms including increased risk of preexisting conditions, immune system impairment, viral survival and transport, and behaviors that increase viral exposure. However, there are challenges in investigating these relationships due to data and methodological issues. This article evaluates the strength of evidence for environment-COVID-19 relationships and discusses environmental actions that can address both the pandemic and health disparities.