A global observational analysis to understand changes in air quality during exceptionally low anthropogenic emission conditions

Sokhi, Ranjeet S.; Singh, Vikas; Querol, Xavier; Finardi, S.; Targino, Admir Créso; Andrade, María de Fátima; Pavlovic, Radenko; Garland, R. M.; Massagué, Jordi; Kong, Shaofei; Baklanov, Alexander; Ren, Lu; Tarasova, Oksana; Carmichael, G. R.; Peuch, Vincent Henri; Anand, Vrinda; Arbilla, Graciela; Badali, Kaitlin; Beig, Gufran; Cerón, Luis Carlos Belalcázar; Bolignano, Andrea; Brimblecombe, Peter; Camacho, Patricia; Casallas, Alejandro; Charland, Jean Pierre; Choi, Jason; Chourdakis, Eleftherios; Coll, Isabelle; Collins, Marty; Cyrys, Josef; Silva, Cleyton Martins da; Giosa, Alessandro Domenico Di; Leo, A. di; Ferro, Camilo; Calderón, Mario Eduardo Gavidia; Gayen, Amiya; Гинзбург, А. С.; Godefroy, Fabrice; González, Yuri; Guevara-Luna, Marco Andrés; Haque, Sk. Mafizul; Havenga, Henno; Herod, Dennis; Hõrrak, Urmas; Hussein, Tareq; Ibarra, Sergio; Jaimes, Mónica; Kaasik, Marko; Ravindra, Khaiwal; Kim, Jhoon; Kousa, Anu; Kukkonen, Jaakko; Kulmala, Markku; Kuula, Joel; Violette, Nathalie La; Lanzani, G.; Liu, Xi; MacDougall, Stephanie; Manseau, Patrick M.; Marchegiani, Giada; McDonald, Brian; Mishra, Swasti Vardhan; Molina, Luisa T.; Mooibroek, D; Mor, Suman; Moussiopoulos, Ν.; Murena, Fabio; Niemi, Jarkko V.; Noe, Steffen M.; Nogueira, Thiago; Norman, Michael; Pérez-Camaño, Juan Luis; Petäj̈ä, Tuukka; Piketh, Stuart; Rathod, Aditi; Reid, Ken; Retama, Armando; Rivera, Olivia; Rojas, Néstor Y.; Rojas-Quincho, Jhojan Pool; José, Roberto San; Sànchez, Odòn; Seguel, Rodrigo; Sillanpää, Salla; Su, Yushan; Tapper, Nigel; Terrazas, Antonio; Timonen, Hilkka; Toscano, Domenico; Tsegas, George; Velders, Guus J. M.; Vlachokostas, Christos; Schneidemesser, Erika von; Vpm, Rajasree; Yadav, Ravi; Žalakevičiūtė, Rasa; Zavala, M.

doi:10.1016/j.envint.2021.106818

Cited by 134 publications

(87 citation statements)

References 80 publications

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“…Moreover, the concentration of O 3 increased three times during the COVID-lockdown period, which was similar to the observation in most Chinese cities (e.g., Chengdu, Shenyang, Wuhan, and Jinan). ( Sharma et al, 2020 ; Sokhi et al, 2021 ). Model results in eastern China suggested that the significant decrease in NO x emissions led to a substantial increase in O 3 concentration because O 3 was sensitive to the VOC reduction after the COVID-19 lockdown ( Chu et al, 2020 ).…”

Section: Resultsmentioning

confidence: 99%

Elevated particle acidity enhanced the sulfate formation during the COVID-19 pandemic in Zhengzhou, China

Yang

Wang

Zhang

et al. 2022

Environmental Pollution

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The significant reduction in PM 2.5 mass concentration after the outbreak of COVID-19 provided a unique opportunity further to study the formation mechanism of secondary inorganic aerosols. Hourly data of chemical components in PM 2.5 , gaseous pollutants, and meteorological data were obtained from January 1 to 23, 2020 (pre-lockdown) and January 24 to February 17, 2020 (COVID-lockdown) in Zhengzhou, China. Sulfate, nitrate, and ammonium were the main components of PM 2.5 during both the pre-lockdown and COVID-lockdown periods. Compared with the pre-lockdown period, even though the concentration and proportion of nitrate decreased, nitrate was the dominant component in PM 2.5 during the COVID-lockdown period. Moreover, nitrate production was enhanced by the elevated O 3 concentration, which was favorable for the homogeneous and hydrolysis nitrate formation despite the drastic decrease of NO 2 . The proportion of sulfate during the COVID-lockdown period was higher than that before. Aqueous-phase reactions of H 2 O 2 and transition metal (TMI) catalyzed oxidations were the major pathways for sulfate formation. During the COVID-lockdown period, TMI-catalyzed oxidation became the dominant pathway for aqueous-phase sulfate formation because the elevated acidity favored the dissolution of TMI. Therefore, the enhanced TMI-catalyzed oxidation affected by the elevated particle acidity dominated the sulfate formation, resulting in the slight increase of sulfate concentration during the COVID-lockdown period in Zhengzhou.

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Section: Resultsmentioning

confidence: 99%

Elevated particle acidity enhanced the sulfate formation during the COVID-19 pandemic in Zhengzhou, China

Yang

Wang

Zhang

et al. 2022

Environmental Pollution

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“…There are different ways to calculate the BAU conditions. In recent studies focused on the COVID-19 lockdown impact on air pollution, the average values on the weeks [47] or the years [48] preceding the event are used as an approximation of the BAU. A limitation of the latter technique is the fact that it does not consider the meteorological conditions, which can significantly modify the assumed BAU pollution concentrations.…”

Section: Assessment Of the Methodsmentioning

confidence: 99%

Gradient Boosting Machine to Assess the Public Protest Impact on Urban Air Quality

et al. 2021

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Political and economic protests build-up due to the financial uncertainty and inequality spreading throughout the world. In 2019, Latin America took the main stage in a wave of protests. While the social side of protests is widely explored, the focus of this study is the evolution of gaseous urban air pollutants during and after one of these events. Changes in concentrations of NO2, CO, O3 and SO2 during and after the strike, were studied in Quito, Ecuador using two approaches: (i) inter-period observational analysis; and (ii) machine learning (ML) gradient boosting machine (GBM) developed business-as-usual (BAU) comparison to the observations. During the strike, both methods showed a large reduction in the concentrations of NO2 (31.5–32.36%) and CO (15.55–19.85%) and a slight reduction for O3 and SO2. The GBM approach showed an exclusive potential, especially for a lengthier period of predictions, to estimate strike impact on air quality even after the strike was over. This advocates for the use of machine learning techniques to estimate an extended effect of changes in human activities on urban gaseous pollution.

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“…Restricted vehicles' movement, closure of industries, and other activities resulted in a significant reduction in anthropogenic emissions of air pollutants. This led to an improvement in the air quality of many cities worldwide [ 3 ], which was far possible to achieve despite several measures. With the halt of all major anthropogenic activities that are prominent sources of air pollution, air quality improved globally [ [4] , [5] , [6] , [7] , [8] , [9] ].…”

Section: Introductionmentioning

confidence: 99%

COVID-19 pandemic: What can we learn for better air quality and human health?

Ravindra¹,

Singh²,

Vardhan³

et al. 2022

Journal of Infection and Public Health

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The COVID-19 lockdown resulted in improved air quality in many cities across the world. With the objective of what could be the new learning from the COVID-19 pandemic and subsequent lockdowns for better air quality and human health, a critical synthesis of the available evidence concerning air pollution reduction, the population at risk and natural versus anthropogenic emissions was conducted. Can the new societal norms adopted during pandemics, such as the use of face cover, awareness regarding respiratory hand hygiene, and physical distancing, help in reducing disease burden in the future? The use of masks will be more socially acceptable during the high air pollution episodes in lower and middle-income countries, which could help to reduce air pollution exposure. Although post-pandemic, some air pollution reduction strategies may be affected, such as car-pooling and the use of mass transit systems for commuting to avoid exposure to airborne infections like coronavirus. However, promoting non-motorized modes of transportation such as cycling and walking within cities as currently being enabled in Europe and other countries could overshadow such losses. This demand focus on increasing walkability in a town for all ages and populations, including for a differently-abled community. The study highlighted that for better health and sustainability there. is also a need to promote other measures such as work-from-home, technological infrastructure, the extension of smart cities, and the use of information technology.

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A global observational analysis to understand changes in air quality during exceptionally low anthropogenic emission conditions

Cited by 134 publications

References 80 publications

Elevated particle acidity enhanced the sulfate formation during the COVID-19 pandemic in Zhengzhou, China

Elevated particle acidity enhanced the sulfate formation during the COVID-19 pandemic in Zhengzhou, China

Gradient Boosting Machine to Assess the Public Protest Impact on Urban Air Quality

COVID-19 pandemic: What can we learn for better air quality and human health?

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