18 Jun 2021

18 Jun 2021

Review status: a revised version of this preprint is currently under review for the journal ACP.

Impact of COVID-19 pandemic related to lockdown measures on tropospheric NO2 columns over Île-de-France

Andrea Pazmiño1, Matthias Beekmann2, Florence Goutail1, Dmitry Ionov3, Ariane Bazureau1, Manuel Nunes-Pinharanda1, Alain Hauchecorne1, and Sophie Godin-Beekmann1 Andrea Pazmiño et al.
  • 1LATMOS/IPSL, UVSQ, Université Paris-Saclay, Sorbonne Université, CNRS, Guyancourt, France
  • 2LISA/IPSL, UMR CNRS 7583, Université Paris Est Créteil, Université de Paris, Créteil, France
  • 3University of Saint Petersburg, Saint Petersburg, Russia

Abstract. The evolution of NO2, considered as proxy for air pollution, was analyzed to evaluate the impact of 1st lockdown (March 17th – May 10th 2020) over île-de-France region (Paris and surroundings). Tropospheric NO2 columns measured by two UV-Visible SAOZ spectrometers were analyzed to compare the evolution of NO2 between urban and suburban sites during the lockdown. The urban site is the observation platform QUALAIR (48°50' N/2°21' E) on the Pierre et Marie Curie Campus of Sorbonne University in the center of Paris. The suburban site is located at Guyancourt (48°46' N/2°03' E), University of Versailles Saint Quentin, 24 km south-west of Paris. Tropospheric NO2 columns above Paris and Guyancourt have shown similar values during the whole lockdown period from March to May 2020. One decade datasets were filtered to consider air masses at both sites with similar meteorological conditions. The median NO2 columns, as well as the surface measurements of AIPARIF (Air Quality Observatory in Ile de France) during the lockdown period in 2020 were compared to the extrapolated values estimated from a linear trend analysis for the 2011–2019 period at each station. Negative NO2 trends of −1.5 Pmolec cm−2 yr−1 (~−6.3 % yr−1) are observed from the columns and of −2.2 μg m−3 yr−1 (~−3.6 % yr−1) from the surface concentration.

The negative anomaly in tropospheric columns in 2020 attributed to lockdown (and related emission reductions) was found to be 56 % at Paris and 46 % at Guyancourt, respectively. Similar anomaly was found in the data of surface concentrations, amounting for 53 % and 28 % at the urban and suburban sites, accordingly.

Andrea Pazmiño 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-2021-456', Anonymous Referee #1, 26 Jul 2021
  • RC2: 'Comment on acp-2021-456', Anonymous Referee #2, 12 Aug 2021

Andrea Pazmiño et al.

Andrea Pazmiño et al.


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Short summary
NO2 tropospheric columns and concentrations at the surface were evaluated to quantify the impact of the lockdown measures in Paris to limit the COVID-19 propagation. Meteorological conditions and NO2 trends were considered. The negative anomaly in tropospheric columns in 2020 attributed to lockdown between March 17 and May 10 (and related emission reductions) were found to be 56 % at Paris and 46 % at a suburban site. A similar anomaly was found in the data of surface concentrations.