Concentrations and Allocation of NO&amp;lt;sub&amp;gt;2&amp;lt;/sub&amp;gt; Emissions to Different Sources in a Distinctive Italian Region after the COVID-19 Lockdown

Marcello Ruberti,Luigi Romano

doi:10.4236/jep.2020.119042

Abstract

Nitrogen dioxide concentrations, being short-lived pollutants, are good indicators of changes in emission sources and economic slowdowns. This analysis focuses on the Greater Salento region (Italy) and aims to monitor, by investigating the relative sources, the changes of NO2 tropospheric concentrations notoriously related to vehicular traffic exhausts and, in general, to fossil fuel combustion processes which are now apparently linked to many COVID-19 patients deaths. The principle objective of this paper is to map the tropospheric NO2 local distribution and to extrapolate, from the overall data of average daily concentrations of NO2 as recorded by the ARPA-Puglia ground-based monitoring stations, the single contributions and their mutual relationships of the different diffuse emission sources (motor vehicles and domestic heating systems) by identifying, the environmental background threshold of this pollutant of each geographic area, thanks to the simplified situation determined by the COVID-19 lockdown. The analyzed territory (the so-called “Greater Salento” or Salento Peninsula) is very unusual because there are two provinces with large industrial settlements, Taranto, with the steel area of ex-ILVA, and Brindisi, with petrochemical and thermoelectric power plants, which enclose a territory, the province of Lecce, free of any industrial plants of such sizes and their environmental impacts. From the results of this study, in addition to confirming the obvious and overall decrease of NO2 concentrations (-23.2% compared to previous year) during the lockdown period, interesting and distinctive local allocations of nitrogen dioxide concentrations to different sources have also emerged: heating household systems, and not road traffic, are the main sources of this dangerous pollutant in this region, with an average quota of 44.3%. The studied regional situation is so significant as to allow broader considerations regarding to other similar international areas.

Highlights

Investigating, with accuracy, the contribution of the different and numerous sources that determine air pollution is not an easy matter because there are many anthropogenic and natural factors, meteorological dynamics and chemical mechanisms [1]
Nitrogen dioxide concentrations, being short-lived pollutants, are good indicators of changes in emission sources and economic slowdowns. This analysis focuses on the Greater Salento region (Italy) and aims to monitor, by investigating the relative sources, the changes of NO2 tropospheric concentrations notoriously related to vehicular traffic exhausts and, in general, to fossil fuel combustion processes which are apparently linked to many COVID-19 patients deaths
The principle objective of this paper is to map the tropospheric NO2 local distribution and to extrapolate, from the overall data of average daily concentrations of NO2 as recorded by the ARPA-Puglia ground-based monitoring stations, the single contributions and their mutual relationships of the different diffuse emission sources by identifying, the environmental background threshold of this pollutant of each geographic area, thanks to the simplified situation determined by the COVID-19 lockdown

Summary

Introduction

Investigating, with accuracy, the contribution of the different and numerous sources that determine air pollution is not an easy matter because there are many anthropogenic and natural factors, meteorological dynamics and chemical mechanisms [1]. The blocking of non-essential production activities and the corresponding provisions of self-quarantine and the population’s mobility restriction and transport shutdown—to which, though in different periods, all those countries affected by the COVID-19 global pandemic [2] have adopted in order to slow down and mitigate their SARS-CoV-2 infection [3]—have provided the exceptional opportunity for scientists to study more deeply, and better understand, the complex underlying problems of air pollution and, in particular, of NO2 tropospheric concentrations on a long-term basis In all those countries where strict containment measures on the population’s mobility, transport and production activities were adopted, there has been a clear improvement in the tropospheric air quality parameters, including a strong decrease of the dangerous concentrations of nitrogen dioxides [4] [5] [6] [7]. Recent studies indicate a strong fatal incidence associated with lung ACE-2 overexpression: in some areas, many COVID-19 patients’ deaths could be linked to a pre-exposure to air pollution, especially NO2 [12] [13] [14]

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Results