Evidence-Based Considerations Exploring Relations between SARS-CoV-2 Pandemic and Air Pollution: Involvement of PM2.5-Mediated Up-Regulation of the Viral Receptor ACE-2.

Marina Borro,Adriano Marcolongo,Ottavia De Luca,Stefano Ferracuti,Paolo Di Girolamo,Maurizio Simmaco,Robert Preissner,Giovanna Gentile

doi:10.3390/ijerph17155573

Abstract

The COVID-19/SARS-CoV-2 pandemic struck health, social and economic systems worldwide, and represents an open challenge for scientists —coping with the high inter-individual variability of COVID-19, and for policy makers —coping with the responsibility to understand environmental factors affecting its severity across different geographical areas. Air pollution has been warned of as a modifiable factor contributing to differential SARS-CoV-2 spread but the biological mechanisms underlying the phenomenon are still unknown. Air quality and COVID-19 epidemiological data from 110 Italian provinces were studied by correlation analysis, to evaluate the association between particulate matter (PM)2.5 concentrations and incidence, mortality rate and case fatality risk of COVID-19 in the period 20 February–31 March 2020. Bioinformatic analysis of the DNA sequence encoding the SARS-CoV-2 cell receptor angiotensin-converting enzyme 2 (ACE-2) was performed to identify consensus motifs for transcription factors mediating cellular response to pollutant insult. Positive correlations between PM2.5 levels and the incidence (r = 0.67, p < 0.0001), the mortality rate (r = 0.65, p < 0.0001) and the case fatality rate (r = 0.7, p < 0.0001) of COVID-19 were found. The bioinformatic analysis of the ACE-2 gene identified nine putative consensus motifs for the aryl hydrocarbon receptor (AHR). Our results confirm the supposed link between air pollution and the rate and outcome of SARS-CoV-2 infection and support the hypothesis that pollution-induced over-expression of ACE-2 on human airways may favor SARS-CoV-2 infectivity.

Highlights

Northern Italy was among the first and worst SARS-CoV-2 affected regions in Europe
Compared to the limit values of 25 μg/m3 for PM2.5 and 50 μg/m3 for PM10 stated by the WHO Air quality guideline [22], large areas in the Po Valley presented diffused and high concentrations of particulate matter, with a peak of intensity roughly corresponding with the Lombardia Region
While PM10 concentrations are typically higher than PM2.5 concentrations, comparable amounts of these two species were found in the last two weeks of February 2020 in most areas of the Po Valley, with temporary situations where PM2.5 concentrations were found to be systematically higher than corresponding PM10 values by approximately 10 μg/m3

Summary

Introduction

Northern Italy was among the first and worst SARS-CoV-2 affected regions in Europe. After about four months from the identification of the primary infection, the Lombardia Region still counts for about half of the total cases, new infections and total deaths. The peculiarity of the pandemic spread in a relatively small part of the country may represent a milestone to dissect and assess single factors contributing to the exacerbation of the pandemic. Industrial production and per capita wealth are distributed from north to south following a descending trend [1]. The high human mobility (national and international) in North

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Conclusion