Characteristics of air quality in different climatic zones of China during the COVID-19 lockdown

Wang, Honglei; Tan, Yue; Lian-xia, Zhang; Zhao, Tianliang; Dai, Qihang; Guan, Tianyi; Ke, Yue; Li, Xia

doi:10.1016/j.apr.2021.101247

Cited by 20 publications

(12 citation statements)

References 67 publications

(88 reference statements)

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Our study found that the classification of city scale, pollution level, and population mobility is consistent with the characteristics of the cluster mappers of the local Moran's I. This distribution characteristic of the population, economy, urban processes, topography, and climate are consistent in China (H. Wang et al, 2021 ). Large urban agglomerations (e.g., the Yangtze River Delta, the Sichuan Basin, the Great Bay area, and Jing-Jin-Ji Region) are densely populated, resulting in serious anthropogenic pollution.…”

Section: Discussionsupporting

confidence: 82%

“…COVID-19 has deeply impacted environmental quality in certain areas in the short term ( He et al, 2021a ; Zhao et al, 2021 ), because of restrictions to limit exposure to the highly contagious virus ( Bashir et al, 2020 ; Gautam, 2020 ; Rugani and Caro, 2020 ; Sharma et al, 2020 ). However, past air quality control studies have primarily focused on specific areas (H. Wang et al, 2021 ). Methods based on large sample cities (including many small- and medium-sized cities) have rarely been examined.…”

Section: Introductionmentioning

confidence: 99%

“…Because there are obvious differences in climate, population distribution, economic structure, and urbanization process in Chinese regions with a vast territory (H. Wang et al, 2021 ), air pollution variation during the lockdown also has regional characteristics. As shown in Table S1 , only a few studies have identified larger lockdown effects in colder, richer, larger, more industrialized, and more air-polluted cities with previous heterogeneity analysis, suggesting interactions with city attributes ( He et al, 2020 ; Hu et al, 2021 ; Shen et al, 2021 ; H. Wang et al, 2021 ; Zeng and Bao, 2021 ). However, this cannot be deduced in all cases.…”

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Association of population migration with air quality: Role of city attributes in China during COVID-19 pandemic (2019–2021)

Luo

Wang

2022

Atmospheric Pollution Research

View full text Add to dashboard Cite

Section: Discussionsupporting

confidence: 82%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Association of population migration with air quality: Role of city attributes in China during COVID-19 pandemic (2019–2021)

Luo

Wang

2022

Atmospheric Pollution Research

View full text Add to dashboard Cite

“…In addition to population density, the factors that cause air pollution are complex [ 9 ], and meteorological aspects have an essential role in their alteration [ 10 , 11 , 12 , 13 , 14 , 15 , 16 , 17 , 18 ], depending on the location. Moreover, disaggregating and quantifying the characteristics to improve air quality is challenging.…”

Section: Introductionmentioning

confidence: 99%

The Long-Term Impact of COVID-19 Lockdowns in Istanbul

Tan

2022

IJERPH

View full text Add to dashboard Cite

The World Health Organization (WHO) have set sustainability development goals to reduce diseases, deaths, and the environmental impact of cities due to air pollution. In Istanbul, although average pollutant concentrations have been on a downward trend in recent years, extreme values and their annual exceedance numbers are high based on the air quality standards of WHO and the EU. Due to COVID-19 lockdowns, statistically significant reductions in emissions were observed for short periods. However, how long the effect of the lockdowns will last is unknown. For this reason, this study aims to investigate the impact of long-term lockdowns on Istanbul’s air quality. The restriction period is approximated to the same periods of the previous years to eliminate seasonal effects. A series of paired t-tests (p-value < 0.05) were applied to hourly data from 12 March 2016, until 1 July 2021, when quarantines were completed at 36 air quality monitoring stations in Istanbul. The findings reveal that the average air quality of Istanbul was approximately 17% improved during the long-term lockdowns. Therefore, the restriction-related changes in emission distributions continued in the long-term period of 476 days. However, it is unknown how long this effect will continue, which will be the subject of future studies. Moreover, it was observed that the emission probability density functions changed considerably during the lockdowns compared to the years before. Accordingly, notable decreases were detected in air quality limit exceedances in terms of both excessive pollutant concentrations and frequency of occurrence, respectively, for PM10 (−13% and −13%), PM2.5 (−16% and −30%), and NO2 (−3% and −8%), but not for O3 (+200% and +540%) and SO2 (−10% and +2.5%).

show abstract

“…The formation mechanisms of typical PM 2.5 pollution episodes over China have been extensively studied to provide references for local governments to take air pollution control measures (Gao et al, 2012;Zhou et al, 2015;Jin et al, 2017;Wu et al, 2020;Wang, et al, 2021a;Wang, et al, 2021b). Normally, meteorological factors play a significant role in the generation, development and end of pollution events through a complex combination of processes, including pollutant transitions, secondary particle production, particle hygroscopic growth and wet removal processes, and are principally responsible for heavy pollution episodes (Pasch et al, 2011;Wang and ChenSun, 2014;Wang et al, 2015;Miao et al, 2017;Yang et al, 2018).…”

Section: Introductionmentioning

confidence: 99%

Joint Occurrence of Heavy PM2.5 Pollution Episodes and Persistent Foggy Days in Central East China

Yang

Liu

2022

Front. Environ. Sci.

View full text Add to dashboard Cite

Although many severe pollution events in Central and East China have been analyzed in recent years, the heavy PM2.5 pollution episode happened on persistent foggy days from January 13 to 18, 2018 was unique, characterized by explosive increase and sharp decrease in PM2.5 (particles with kinetic equivalent diameter less than or equal to 2.5 microns) concentration. Based on hourly data of ground level meteorological parameters, PM2.5 data and CALIPSO-based (the Cloud-Aerosol Lidar and Infrared Pathfinder Satellite Observation) aerosol data, combined with ECMWF (European Centre for Medium-Range Weather Forecasts) reanalysis data and radiosonde temperature profile, a comprehensive analysis was conducted to reveal the meteorological reasons for the evolution of the episode at horizontal and vertical scales. The PM2.5 concentration experienced four stages: a slow-increase phase, rapid-increase phase, rapid-decrease phase, and rebound phase. Results show that because Central and East China (CEC) were located at the back of a high-pressure system, humid southerly winds and near surface inversion (NSI) were responsible for the slow accumulation of pollutants. The rapid-increase phase was attributed to pollution transport at both ground level and in the lower troposphere because of weak cold air invasion. The significant subsidence at 500 hPa and 700 hPa intensified the NSI and led to dense fog. In that case, corresponding to the supersaturated atmosphere, the particles entered the fog droplets and were scavenged partly by deposition at night and were resuspended on the next day when the atmosphere was unsaturated. Our findings provide convincing evidence that surface PM2.5 rapid-decrease phase and the rebound phase were closely associated with dense fog process.

show abstract

Characteristics of air quality in different climatic zones of China during the COVID-19 lockdown

Cited by 20 publications

References 67 publications

Association of population migration with air quality: Role of city attributes in China during COVID-19 pandemic (2019–2021)

Association of population migration with air quality: Role of city attributes in China during COVID-19 pandemic (2019–2021)

The Long-Term Impact of COVID-19 Lockdowns in Istanbul

Joint Occurrence of Heavy PM2.5 Pollution Episodes and Persistent Foggy Days in Central East China

Contact Info

Product

Resources

About