Assessing the impact of long-term exposure to nine outdoor air pollutants on spatial spread of Covid-19: evidence from 107 Italian provinces

Abstract The coronavirus (COVID-19) pandemic has dramatically changed every aspect of people’s lives around the world over the past year and a half. Although the global vaccination campaign is progressing worldwide, new variants of COVID-19 have emerged, driving many countries into a fourth wave of COVID-19 contagion. This paper investigates the air quality in 107 Italian provinces in the period 2014–2019 and the association between long-term exposure to nine outdoor air pollutants and the prevalence of COVID-19 in the same areas. The methods used were negative binomial (NB) regressions, ordinary least squares (OLS) models, and spatial autoregressive models with autoregressive disturbances (SARAR). The air pollutants examined were common air pollutants (NO2, O3, PM2.5, PM10), polycyclic aromatic hydrocarbons (PAHs) (benzene and BaP), and heavy metals (As, Cd, and Ni). The results showed that i) common air pollutants were generally highly and positively correlated with density of large firms, energy and gas consumption, public transport, and the livestock sector; and ii) long-term exposure to NO2, PM2.5, PM10, benzene, BaP, and Cd was positively and significantly correlated with the spread of COVID-19, even after controlling for cofactors and spatial effects. This outcome seems of interest and relevance because PAHs and heavy metals have not been considered at all in recent literature. It also seems to suggest the need for a national strategy to drive down air pollutant concentrations in order to cope better with possible future pandemics.