Reduction of Air Pollution in Poland in Spring 2020 during the Lockdown Caused by the COVID-19 Pandemic

Patryk Tadeusz Grzybowski,Krzysztof Mirosław Markowicz,Jan Paweł Musiał

doi:10.3390/rs13183784

Patryk Tadeusz Grzybowski, Krzysztof Mirosław Markowicz + Show 1 more

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https://doi.org/10.3390/rs13183784

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Abstract

The COVID-19 pandemic has affected many aspects of human well-being including air quality. The present study aims at quantifying this effect by means of ground-level concentrations of NO2, PM2.5, as well as aerosol optical depth (AOD) measurements and tropospheric NO2 column number density (NO2 TVCD), during the imposed governmental restrictions in spring 2020. The analyses were performed for both urban and non-built-up areas across the whole of Poland accompanied by Warsaw (urban site) and Strzyzow (a background site). The results revealed that mean PM2.5 concentrations in spring 2020 for urban and non-built-up areas across Poland and for Warsaw were 20%, 23%, 15% lower than the 10-year average, respectively. Analogous mean NO2 concentrations were lower by 20%, 18%, 30% and NO2 TVCD revealed 9%, 4%, 9% reductions in 2020 as compared to 2019. Regarding mean AOD, retrieved from MERRA-2 reanalysis, it was found that for the whole of Poland during spring 2020 the reduction in AOD as compared to the 10-year average was 15%. The contribution of the lockdown within total air pollution reduction is not easily assessable due to anomalous weather conditions in 2020 which resulted in advection of clean air masses identified from MERRA-2 reanalysis and Strzyzow observatory.

Highlights

This research consists of data analysis obtained from ground-based (PM2.5, NO2, aerosol optical depth (AOD), equivalent black carbon concentration, aerosol scattering coefficient) and satellite observation for the NO2 column, as well as from model simulations and reanalysis
Preliminary results for PM2.5 atmospheric concentration within this study revealed a need for an extended analysis of background aerosol concentration in order to facilitate interpretation of the unusual fluctuations, which occurred in spring 2020
The analyses were based on multi-source datasets consisting of in-situ measurements from GIOS air quality stations, in-situ aerosol properties measured at the Strzyzow Aerosol Robotic Network (AERONET) site, NO2 derived from Sentinel-5P satellite data, MERRA-2 climatic reanalysis, climatic statistics based on surface synoptic observations, directions of airmass advections from Hybrid Single-Particle Lagrangian Integrated Trajectory (HYSPLIT) model reanalysis, radiosonde measurements from Legionowo weather station, and ancillary data on vehicle traffic

Summary

Introduction

Preliminary results for PM2.5 atmospheric concentration within this study revealed a need for an extended analysis of background aerosol concentration in order to facilitate interpretation of the unusual fluctuations, which occurred in spring 2020. The main drivers for AOD reduction in 2020 with respect to the 2010–2019 average were sulphates (−18%), mineral dust (−16%) and organic carbon (−15%), black carbon (−8%) while sea salt increased by 18% (Table 2). This indicates the advection of clear atlantic air masses from NW and W which dominated Poland in April–May 2020 (Figure 2b)

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