The Relation between Atmospheric Aerosol Concentration and SARS-CoV-2 Variants’ Infection and Mortality Rates in the United States: A Remote-Sensing Perspective

Abstract

Numerous studies have highlighted the health benefits associated with reducing aerosol particles and other pollutants. Recent studies have shown a positive correlation between exposure to aerosol particles and COVID-19 cases. In this study, we investigate the relationship between aerosol particle concentration and COVID-19 variants’ infection and mortality rates. Remote-sensing data on aerosol optical depth (AOD), a surrogate for atmospheric aerosol levels, were collected and analyzed in three regions within the states of California, Illinois, and North and South Carolina. These regions were selected to reflect the variability in aerosol concentration and anomalies during the COVID-19 period (2020–2022) compared to a reference period (2010–2019). We found consistent positive linear correlations across most regions between COVID-19 mortality rates and AOD levels below 0.2. These correlations were found to be independent of the change in aerosol levels relative to the reference period. In North and South Carolina, the Delta variant was associated with not only a high mortality rate but also a steeper increase in mortality rate per AOD of 39.6 ± 1.5 (R2 = 0.87) compared to Alpha at 10.5 ± 0.3 (R2 = 0.85). However, due to the lower mortality rate of the Delta variant compared to the Alpha variant in Illinois, the Delta variant has a lower correlation slope of 28.3 ± 1 (R2 = 0.94) compared to the Alpha variant at 52.1 ± 1.8 (R2 = 0.78). No correlation between mortality rate and AOD was observed for the Omicron variants in any of the investigated regions except in California where a weak positive correlation was evident. Our findings establish a compelling link between aerosol concentrations and SARS-CoV-2 infection and mortality. Our results underscore the urgent need for further research to elucidate the underlying mechanisms and broader implications, leading to more sustainable solutions to curb the airborne transmission of COVID-19 viruses and other viral infections in general.