20 Dec 2021
20 Dec 2021
Status: a revised version of this preprint is currently under review for the journal ACP.

PM10 variation, composition, and source analysis in Tuscany (Italy) following the COVID-19 lockdown restrictions

Fabio Giardi1,2, Silvia Nava1,2, Giulia Calzolai2, Giulia Pazzi1,2, Massimo Chiari2, Andrea Faggi1, Bianca Patrizia Andreini3, Chiara Collaveri3, Elena Franchi4, Guido Nincheri4, Alessandra Amore5, Silvia Becagli5, Mirko Severi5, Rita Traversi5, and Franco Lucarelli1,2 Fabio Giardi et al.
  • 1Department of Physics and Astronomy, University of Florence, Sesto Fiorentino (FI), 50019, Italy
  • 2National Institute of Nuclear Physics (INFN), Sesto Fiorentino (FI), 50019, Italy
  • 3Environmental Protection Agency of Tuscany - Regional Center for Quality Air Protection, Livorno, 57126, Italy
  • 4Environmental Protection Agency of Tuscany - Central wide area laboratory, Florence, 50144, Italy
  • 5Department of Chemistry, University of Florence, Sesto Fiorentino (FI), 50019, Italy

Abstract. To control the spread of COVID-19, in March 2020 exceptional restrictive measures were taken imposing a radical change in the lifestyle of millions of citizens around the world, albeit for a short period of time. The national lockdown, which in Italy lasted from 10 March to 18 May 2020, was a unique opportunity to observe the variation in air quality in urban environments in a condition of almost total traffic block and a strong reduction in work activities. In this paper, the data from seventeen urban monitoring sites in Tuscany are presented by comparing PM and NO2 of the two months before the start of the lockdown and the two after with the corresponding months of the previous three years. The results show that the total load of PM2.5 and PM10 decreased but it did not exhibit significant changes compared to previous years, while NO2 undergoes a drastic reduction. For three of these sites, the chemical composition of the collected samples was measured by thermo-optical, ion chromatography and PIXE analysis, and the application of multivariate PMF analysis allowed the PM10 source identification and apportionment. Thanks to these analyses it was possible to explain the low sensitiveness of PM10 to the lockdown effects as due to different, sometimes opposite, behaviors of the different sources that contribute to PM. The results clearly indicated a decline in pollution levels related to urban traffic and an increase in the concentration of sulfate for all sites during the lockdown period.

Fabio Giardi et al.

Status: final response (author comments only)

Comment types: AC – author | RC – referee | CC – community | EC – editor | CEC – chief editor | : Report abuse
  • RC1: 'Comment on acp-2021-995', Anonymous Referee #1, 17 Jan 2022
  • RC2: 'Comment on acp-2021-995', Anonymous Referee #2, 28 Mar 2022
  • AC1: 'Response to the referee comments on acp-2021-995', Fabio Giardi, 16 May 2022

Fabio Giardi et al.

Fabio Giardi et al.


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Short summary
The restrictions adopted for the containment of COVID-19 infections offered a unique opportunity to study urban particulate emissions in almost absence of traffic, which is one of the main sources in the urban environment. However, the drastic decrease of this source of particulate matter during the months of national lockdown did not lead to an equal decrease in the total particulate load. This is due to the opposite behavior shown by different sources, especially those of the secondary type.