Effects of the COVID-19 Lockdown on Urban Light Emissions: Ground and Satellite Comparison

Abstract

’Lockdown’ periods in response to COVID-19 have provided a unique opportunity to study the impacts of economic activity on environmental pollution (e.g. NO2, aerosols, noise, light). The effects on NO2 and aerosols have been very noticeable and readily demonstrated, but that on light pollution has proven challenging to determine. The main reason for this difficulty is that the primary source of nighttime satellite imagery of the earth is the SNPP-VIIRS/DNB instrument, which acquires data late at night after most human nocturnal activity has already occurred and much associated lighting has been turned off. Here, to analyze the effect of lockdown on urban light emissions, we use ground and satellite data for Granada, Spain, during the COVID-19 induced confinement of the city’s population from March 14 until May 31, 2020. We find a clear decrease in light pollution due both to a decrease in light emissions from the city and to a decrease in anthropogenic aerosol content in the atmosphere which resulted in less light being scattered. A clear correlation between the abundance of PM10 particles and sky brightness is observed, such that the more polluted the atmosphere the brighter the urban night sky. An empirical expression is determined that relates PM10 particle abundance and sky brightness at three different wavelength bands.

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

“…Observations on the magnitude of the NO2 decrease due to COVID-19 control measures were in agreement with recent research on this phenomenon in different countries (Cameletti, 2020;Dutheil et al, 2020;Kumari & Toshniwal, 2020;Muhammad et al, 2020;Rugani & Caro, 2020;Zaib et al, 2021;Zambrano-Monserrate et al, 2020). Recent investigations addressed the phenomenon of nighttime light's dimming during confinements (Bustamante-Calabria et al, 2021;Christopher D. Elvidge et al, 2020;Ghosh et al, 2020;S. Zheng et al, 2021), however, these studies focused on specific urban areas where particularly there was an effect on nighttime illumination, therefore dimming was not a general and widespread phenomenon in many areas.…”

“…The use of night light data for economic growth studies is well known (Beyer et al, 2018;Ghosh et al, 2017;Ivan et al, 2020;Prakash et al, 2019). Besides, there are recent studies that addressed the phenomenon of dimming night lights during COVID-19 lockdowns (Bustamante-Calabria et al, 2021;Elvidge et al, 2020;Ghosh et al, 2020;S. Zheng et al, 2021).…”

Environmental risks from artificial nighttime lighting widespread and increasing across Europe

“…This is a simple outcome of the spectral sensitivity of the associated sensors. However, this may have very important implications because the emission intensities measured by SNPP/VIIRS-DNB are used for a wide diversity of purposes, including the estimation of levels of human population density and urbanization ( 41 , 42 ), economic activity ( 43 ) and wilderness areas ( 44 ), and the impacts of the coronavirus disease 2019 pandemic ( 45 , 46 ).…”

Impacts of the COVID‐19 pandemic on human–nature interactions: Pathways, evidence and implications

“…air and water pollutants, noise, artificial light) due to reduced economic activity and human mobility (e.g. Bustamante‐Calabria et al., 2021; Chen et al., 2020; Derryberry et al., 2020; Mandal & Pal, 2020; Venter, Aunan, et al., 2020; Venter, Barton, et al., 2020), and in some there has been a reduction in management (e.g. cutting vegetation) associated with greenspaces (e.g.…”