Nighttime Light Emissions Explain the Decline in No2 During a Covid-19-Induced Total Lockdown in France

Abstract

Referring to a total lockdown due to COVID-19 in Metropolitan France, this study investigates the geospatial correlation between nighttime light emission and the relative change of NO2 air pollution (dNO2 %). To address the research problem, near-surface NO2 data and nighttime light data were implemented. Stable night lights were obtained for a long period on average (2014-2019) using Day-Night Band (DNB) data from the Visible Infrared Imaging Radiometer Suite (VIIRS). The relative change in tropospheric NO2 was calculated using Sentinel-5P satellite data from the TroposphericMonitoring Instrument (TROPOMI). The dNO2 calculation was performed considering an equivalent reference period (April 2019) to the major lockdown period in France (April 2020). The correlation between the variables DNB nighttime lights and dNO2 was tested with a statistical T-test. The findings revealed an intense phenomenon of decreasing NO2 air pollution in France (decreases by -25% to -50%). Decreases < -50% were mainly recorded in the greater Paris metropolitan area, in Alsace, and other locations. The results showed a strong and statistically significant inverse geospatial correlation between the two variables under anti-COVID-19 control measures. The higher was the emission of nighttime lights, the higher was the degree of tropospheric NO2 decrease in the regions of France (R 2 =0.72). It is concluded that employing remote sensing techniques, DNB nighttime light is a reliable indicator to estimate the degree of air decontamination. DNB as an independent variable is recommended for future research on changes in the concentration of other pollutant gases.

Impact of Covid-19 Confinement on No2 Emissions in Mexico: Temporal Analysis and Outlook for Air Quality

“…Once all sectors resume normally, the amount of NO2 emissions appears to be picking up. Similar behaviors were observed worldwide, the decreases during confinement were: ➢ 39.1 % for Buenos Aires in Argentina (Represa et al, 2021) ➢ 58 % for Sao Paulo in Brasil (Debone et al, 2020) ➢ 30% approximately in European countries such as Italy (Bassani et al, 2021), France (Kumar et al, 2020) and Spain (Cárcel-Carrasco et al, 2021) ➢ Decreases < -50% were mainly recorded in the greater Paris metropolitan area, in Alsace, and other locations of France (Kovacs, 2022) ➢ 30% in populated cities in China (Liu et al, 2021) ➢ 42% in India (Liu et al, 2021) but in cities like Delhi by 52.68% (Siddiqui et al, 2022) ➢ 34.9% on average in in western regions of the United States such as California, 31% in Los Angeles (Naeger and Murphy, 2020) and in southwestern United States (Dutta et al, 2021) ➢ the average NO2 concentrations in Tabriz, Isfahan, and Mashhad in 2020 decreased by 19%, 13% and 17%, respectively, compared to those in 2019 (Shami et al, 2022) ➢ 9.5% throughout Thailand after the curfew was imposed, while in the Bangkok metropolitan area it decreased by 20.1% (Oo et al, 2021) ➢ in the capital of Ukraine, the monthly average of the tropospheric NO2 column in April 2022 was almost 60% lower than in 2019 and 2021, and about 40% lower than in 2020 (Ialongo et al, 2023).…”

Determination of the human impact on the drop in NO2 air pollution due to total COVID-19 lockdown using Human-Influenced Air Pollution Decrease Index (HIAPDI)

“…As a result of this impact, an immediate decline in air pollution was observed in France and the whole of Europe ( Ikhlasse et al, 2021 ; Magazzino et al, 2020 ; Piazzola et al, 2021 ; Sbai et al, 2021 ). Other authors pointed to the connection between economic development and loss of air pollution ( Kovács, 2022 ; Kovács & Haidu, 2021 ; Magazzino et al, 2021 ; Mele & Magazzino, 2021 ). Despite this, the correlation between human influence on land use and decreased near-surface air pollution due to lockdown have yet to be robustly investigated.…”