Particulate Matter and COVID-19 Disease Diffusion in Emilia-Romagna (Italy). Already a Cold Case?

Giovanni Delnevo,Marco Roccetti,Silvia Mirri

doi:10.3390/computation8020059

Abstract

As we prepare to emerge from an extensive and unprecedented lockdown period, due to the COVID-19 virus infection that hit the Northern regions of Italy with the Europe’s highest death toll, it becomes clear that what has gone wrong rests upon a combination of demographic, healthcare, political, business, organizational, and climatic factors that are out of our scientific scope. Nonetheless, looking at this problem from a patient’s perspective, it is indisputable that risk factors, considered as associated with the development of the virus disease, include older age, history of smoking, hypertension and heart disease. While several studies have already shown that many of these diseases can also be favored by a protracted exposure to air pollution, there has been recently an insurgence of negative commentary against authors who have correlated the fatal consequences of COVID-19 (also) to the exposition of specific air pollutants. Well aware that understanding the real connection between the spread of this fatal virus and air pollutants would require many other investigations at a level appropriate to the scale of this phenomenon (e.g., biological, chemical, and physical), we propose the results of a study, where a series of the measures of the daily values of PM2.5, PM10, and NO2 were considered over time, while the Granger causality statistical hypothesis test was used for determining the presence of a possible correlation with the series of the new daily COVID19 infections, in the period February–April 2020, in Emilia-Romagna. Results taken both before and after the governmental lockdown decisions show a clear correlation, although strictly seen from a Granger causality perspective. Moving beyond the relevance of our results towards the real extent of such a correlation, our scientific efforts aim at reinvigorating the debate on a relevant case, that should not remain unsolved or no longer investigated.

Highlights

COVID-19 has originated in Wuhan, China in late 2019, several provinces of northernItaly have soon become among the hardest-hit regions in Europe
In this study we are interested in reasoning around the plausibility of a correlation between air pollution and the spread of COVID-19 infections in the Emilia-Romagna region, by subjecting such hypothesis to a statistical hypothesis testing from a Granger-causality perspective
We present the results returned by our Granger causality testing model, differentiating between those illustrating the situation before the lockdown measures were adopted that contained the infection surge, and those showing the ex-post situation

Summary

Introduction

COVID-19 has originated in Wuhan, China in late 2019, several provinces of northernItaly have soon become among the hardest-hit regions in Europe. While we are aware that what went wrong will be a subject of studies for years, we are concerned, here, with the fact that COVID-19 manifests as a severe respiratory disease, mostly pneumonia This motivates why many researchers have focused their attention on the potential relationship between the exposure to particulate pollution and the rapid contagion brought by this virus. Neither the Granger causality method, nor any other statistical test can provide a final and convincing evidence that two phenomena are correlated, from an epistemological viewpoint, if one has neither a clear knowledge of the motivation that causes that relationship, nor has developed sufficient experiments at a scale that should be appropriate to the observed phenomena With this regard, the Granger causality approach suffers from an additional problem.

Methods

Results

Conclusion