Quantifying Air Pollutant Variations during COVID-19 Lockdown in a Capital City in Northwest China

Feng, Rong; Xu, Hongmei; Wang, Zexuan; Gu, Yan; Liu, Zhe; Zhang, Hai‐Jing; Zhang, Tian; Wang, Qiyuan; Zhang, Qian; Liu, Suixin; Shen, Zhenxing; Wang, Qin

doi:10.3390/atmos12060788

Cited by 19 publications

(11 citation statements)

References 73 publications

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“…This study and most related studies in other cities have similar findings. Same as the study by Cao, Feng and Lian et al [ 14 , 15 , 47 ], this study found an increase in O 3 values in Wuhan during the city closure and the main reason for this phenomenon may be related to the change in NOx, which is yet to be further investigated. However, this study did not take into account other factors that influence AQI, including temperature, wind, regional transport patterns and precipitation that are not identical for each year among years.…”

Section: Discussionsupporting

confidence: 62%

“…However, they agreed that overall source control measures should be implemented to improve urban ambient air quality [ 17 ]. In addition, studies by Cao and Feng et al have found some negative effects of city closure, reflected in the increase in O 3 pollution [ 14 , 15 ].…”

Section: Introductionmentioning

confidence: 99%

“…Cui, Cao and Feng et al studied the air quality in Dongying City, Shijiazhuang City and Xi'an City of China during and before and after the city closure. They found that (1) urban blockade had an improving effect on air quality in Dongying during the pandemic [13]; (2) the blockade reduced the emission of pollution sources to a certain extent and the pollutant concentrations of PM 2.5 , PM 10 , NO 2 , SO 2 and CO all decreased in Shijiazhuang [14]; (3) NO 2 levels in Xi'an substantially decreased during the city closure [15]. Tao et al used a TVP-VAR model to analyze the dynamic relationship between pandemic, economy and air quality in Beijing from January to August 2020, showing the positive impact of the urban blockade on air management.…”

Section: Introductionmentioning

confidence: 99%

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Analysis of Spatial and Temporal Changes of AQI in Wuhan City under the Urban Blockade of COVID-19 Pandemic

Yang

Sun

2022

IJERPH

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Wuhan was the primary city in the world to adopt lockdown measures during the Coronavirus Disease 2019 pandemic. The influence of the abrupt halt of human activities on the air quality of Wuhan is a subject of considerable attention. This study is based on air quality data from 21 monitoring stations in Wuhan from 2016 to 2020. The lag effect and seasonal factors of AQI were taken into account to analyze the changes in air quality in Wuhan under the influence of the pandemic blockade. The results showed the following during the city closure: (1) A lagging effect is observed in air quality changes, with the change point occurring on the 14th day after the city closure; (2) the air quality index is substantially decreased, demonstrating a reduction in spatial differences; (3) NO2, PM10, and PM2.5 significantly decreased whilst O3 increased, and SO2 and CO did not change significantly; (4) except for the insignificant changes in spatial differences of PM10, all pollutants demonstrated a changing pattern of decreasing geographical differences. This paper provides a reference for studying the influence of human activities on the natural environment.

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Section: Discussionsupporting

confidence: 62%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Analysis of Spatial and Temporal Changes of AQI in Wuhan City under the Urban Blockade of COVID-19 Pandemic

Yang

Sun

2022

IJERPH

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“…The decrease is pronounced in the Ruhr area and in urban areas such as Cologne, Frankfurt, Munich, and Berlin with reductions between 21% and 38%, attributable to strongly reduced road traffic and industrial production, but also to lower NO 2 levels in 2020 before the lockdown and meteorological conditions that are not further disentangled here. A detailed analysis of the lockdown effects on tropospheric NO 2 and their statistical significance considering source attributions of different sectors (Petit et al 2021;Feng et al 2021;Putaud et al 2021), adjustments to multiannual trend effects (Bekbulat et al 2020), or corrections for meteorological influences (Zhou et al 2012;Goldberg et al 2020) is out of scope of this paper. However, the presented findings are in the range of more detailed studies that consider wind corrections and adjustments to trend effects, but focus on different periods of the lockdown (e.g., Liu et al 2020;Goldberg et al 2020).…”

Section: Bluesky Flight Strategy and Scopementioning

confidence: 99%

Cleaner Skies during the COVID-19 Lockdown

Voigt

Lelieveld

Schläger

et al. 2022

Bulletin of the American Meteorological Society

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During spring 2020, the COVID-19 pandemic caused massive reductions in emissions from industry, ground and airborne transportation. To explore the resulting atmospheric composition changes, we conducted the BLUESKY campaign with two research aircraft and measured trace gases, aerosols, and cloud properties from the boundary layer to the lower stratosphere. From 16 May to 9 June 2020, we performed 20 flights in the early COVID-19 lockdown phase over Europe and the Atlantic Ocean. We found up to 50% reductions in boundary layer nitrogen dioxide concentrations in urban areas from GOME-2B satellite data, along with carbon monoxide reductions in the pollution hot spots. We measured 20 to 70% reductions in total reactive nitrogen, carbon monoxide and fine mode aerosol concentration in profiles over German cities compared to a 10-year data set from passenger aircraft. The total aerosol mass was significantly reduced below 5 km altitude, and the organic aerosol fraction also aloft, indicative of decreased organic precursor gas emissions. The reduced aerosol optical thickness caused a perceptible shift in sky color towards the blue part of the spectrum (hence BLUESKY) and increased shortwave radiation at the surface. We find that the 80% decline in air traffic led to substantial reductions in nitrogen oxides at cruise altitudes, in contrail cover, and in resulting radiative forcing. The light extinction and depolarization by cirrus were also reduced in regions with substantially decreased air traffic. General circulation-chemistry model simulations indicate good agreement with the measurements when applying a reduced emission scenario. The comprehensive BLUESKY dataset documents the major impact of anthropogenic emissions on the atmospheric composition.

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“…Air quality is deteriorating due to anthropogenic activities (e.g. vehicle exhaust, industrial emissions, fossil fuel combustion, resident, and household smoking and heating) (Feng et al 2021 ; Ismail et al 2021 ). Exhausts from motor vehicles cause about 50% of air pollution in Iran (Ghaffarpasand et al 2020 ).…”

Section: Introductionmentioning

confidence: 99%

The COVID-19 Pandemic: Quantification of Temporal Variations in Air Pollutants Before, During and Post the Lockdown in Jeddah City, Saudi Arabia

et al. 2022

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The government of Saudi Arabia imposed a strict lockdown between March and July 2020 to stop the spread of the coronavirus disease (COVID-19), which has led to a sharp decline in economic activities. The daily temporal variations of PM 10 , PM 2.5 , carbon monoxide (CO), nitrogen dioxide (NO 2 ), and ozone (O 3 ) were used to investigate the changes in air quality in response to COVID-19 lockdown control measures from January to December 2020 in Jeddah, Saudi Arabia. Meteorological parameters (wind speed, direction, temperature, relative humidity) were also analyzed to understand the changes during the pandemic. As a result, significant reductions in the concentrations of NO 2 (– 44.5%), CO (– 41.5%), and PM 2.5 , PM 10 (– 29.5%, each) were measured in the capital city of Jeddah during the quarantine compared to the pre-lockdown average. In contrast, the lockdown caused a significant increase in O 3 by 41%. The changes in air quality during the COVID-19 outbreak by comparing the average pollutant concentration before lockdown (January 1–March 21, 2020) and the following 12 weeks during the partial lockdown (March 22–July 28, 2020), reveal a very significant decrease in pollutants, and consequently a significant improvement in air quality. Observed differences are attributable to changes in point source emissions associated with changes in localized activities, possibly related to decreased economic and industrial activity in response to the lockdown. The results of the present study show during the study period indicated a positive response to lockdown during the COVID-19 pandemic. Furthermore, the results can be used to establish future control measures and strategies to improve air quality.

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Quantifying Air Pollutant Variations during COVID-19 Lockdown in a Capital City in Northwest China

Cited by 19 publications

References 73 publications

Analysis of Spatial and Temporal Changes of AQI in Wuhan City under the Urban Blockade of COVID-19 Pandemic

Analysis of Spatial and Temporal Changes of AQI in Wuhan City under the Urban Blockade of COVID-19 Pandemic

Cleaner Skies during the COVID-19 Lockdown

The COVID-19 Pandemic: Quantification of Temporal Variations in Air Pollutants Before, During and Post the Lockdown in Jeddah City, Saudi Arabia

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