Influence of COVID-19 Event on Air Quality and their Association in Mainland China

Chen, Qixiang; Huang, Chuanjun; Yuan, Yuan; Tan, He-Ping

doi:10.4209/aaqr.2020.05.0224

Cited by 79 publications

(57 citation statements)

References 22 publications

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“…In particular, we observed a nationwide increase of O 3 during the lockdown period, except for the western area. Similarly, increased O 3 concentrations were observed during the lockdown period in several cities around world (Chen et al, 2020b;Collivignarelli et al, 2020;Dantas et al, 2020;Kerimray et al, 2020), which may be explained by a significant reduction of NO 2 concentrations (Sicard et al, 2020).…”

Section: Wind Direction (°)mentioning

confidence: 87%

Changes in Air Quality during the COVID-19 Lockdown in Singapore and Associations with Human Mobility Trends

Tartarini

2020

Aerosol Air Qual. Res.

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On the 7 th of April, the Singaporean government enforced strict lockdown measures with the aim of reducing the transmission chain of the coronavirus disease 2019. This had a significant impact on the movement of people within the country. Our study aims to quantify the impact that these measures had on outdoor air pollution levels. We obtained air quality and weather data from April 2016 to May 2020, satellite data for 2019 and 2020 and mobility data for 2020 from Apple, Google, and the Singaporean Housing & Development Board. We determined that outdoor air pollution during the lockdown significantly decreased when compared with the same period in the previous four years even if we included corrections for long time trends in the analysis. The concentrations of the following pollutants PM 10 , PM 2.5 , NO 2 , CO, and SO 2 decreased by 23, 29, 54, 6, and 52%, respectively, whilst that of O 3 increased by 18%. The Pollutant Standard Index decreased by 19%. The trends of PM 2.5 and NO 2 were significantly correlated with mobility data. The NO 2 and SO 2 tropospheric concentrations and the total aerosol optical depth at 550 nm obtained from satellite data during the lockdown in 2020 were also lower than during the same period in 2019. Our results can be used to evaluate possible mitigation strategies for outdoor air quality in a longer term beyond this lockdown.

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Section: Wind Direction (°)mentioning

confidence: 87%

Changes in Air Quality during the COVID-19 Lockdown in Singapore and Associations with Human Mobility Trends

Tartarini

2020

Aerosol Air Qual. Res.

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“…China: (Agarwal et al, 2020;Chauhan and Singh, 2020;Chen et al, 2020a;Chen et al, 2020c;Chen et al, 2020d;Fan et al, 2020;G Huang and Sun, 2020;Lian et al, 2020;Liu et al, 2020c;Miyazaki et al, 2020;Nichol et al, 2020;Pei et al, 2020;Shakoor et al, 2020;Shi and Brasseur, 2020;Silver et al, 2020;Wan et al, 2020;Wang et al, 2020a;Wang et al, 2020b;Wang et al, 2020f;Xu et al, 2020c;Zhang et al, 2020a;Yuan et al, 2021) Other: (Ghahremanloo et al, 2020;Han et al, 2020;Ju et al, 2020;Ma and Kang, 2020;Zhang et al, 2020b) South Asia India: (Bedi et al, 2020;Beig et al, 2020;Biswal et al, 2020;Chatterjee et al, 2020;Gautam et al, 2020;Harshita and Vivek, 2020;Jain and Sharma, 2020;Kant et al, 2020;Kumari and Toshniwal, 2020;Panda et al, 2020;Ranjan et al, 2020;Selvam et al, 2020;Sharma et al, 2020a;Siddiqui et al, 2020;Singh and Chauhan, 2020;…”

Section: East Asiaunclassified

“…The median transportation contribution for Annex I countries was 44% (36%-56%), 14% (8%-19%), and 25% (17%-44%) for the NO x , primary PM 2.5 , and CO emissions, respectively, whereas for Annex II countries, it was 29% (5%-49%), 9% (2%-42%), and 35% (1%-75%). Although the contribution of transportation emissions varied for the above pollutants, it is evident that East Asia China (Agarwal et al, 2020), (Bao and Zhang, 2020), a (Bauwens et al, 2020), (Chen et al, 2020c), (Diamond and Wood, 2020), (Forster et al, 2020), (Gautam, 2020a), (Griffith et al, 2020) (Zhang et al, 2021), (Liu et al, 2020b), (Liu et al, 2020c), (Wang et al, 2021), a (Su et al, 2020), (Miyazaki et al, 2020), (Huang and Sun, 2020), (Wang and Zhang, 2020), (Xu et al, 2020b), a (Park et al, 2020) Japan (Ghahremanloo et al, 2020), (Ma and Kang, 2020), a (Fu et al, 2020) South Korea (Fu et al, 2020), (Han et al, 2020), a (Ju et al, 2020), a (Bauwens et al, 2020), (Ma and Kang, 2020), a (Ghahremanloo et al, 2020) Taiwan (Forster et al, 2020) (continued)…”

Section: "Business As Usual" Emission Inventorymentioning

confidence: 99%

The global impacts of COVID-19 lockdowns on urban air pollution

Gkatzelis

Gilman

Brown

et al. 2021

Elementa: Science of the Anthropocene

132

154

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The coronavirus-19 (COVID-19) pandemic led to government interventions to limit the spread of the disease which are unprecedented in recent history; for example, stay at home orders led to sudden decreases in atmospheric emissions from the transportation sector. In this review article, the current understanding of the influence of emission reductions on atmospheric pollutant concentrations and air quality is summarized for nitrogen dioxide (NO2), particulate matter (PM2.5), ozone (O3), ammonia, sulfur dioxide, black carbon, volatile organic compounds, and carbon monoxide (CO). In the first 7 months following the onset of the pandemic, more than 200 papers were accepted by peer-reviewed journals utilizing observations from ground-based and satellite instruments. Only about one-third of this literature incorporates a specific method for meteorological correction or normalization for comparing data from the lockdown period with prior reference observations despite the importance of doing so on the interpretation of results. We use the government stringency index (SI) as an indicator for the severity of lockdown measures and show how key air pollutants change as the SI increases. The observed decrease of NO2 with increasing SI is in general agreement with emission inventories that account for the lockdown. Other compounds such as O3, PM2.5, and CO are also broadly covered. Due to the importance of atmospheric chemistry on O3 and PM2.5 concentrations, their responses may not be linear with respect to primary pollutants. At most sites, we found O3 increased, whereas PM2.5 decreased slightly, with increasing SI. Changes of other compounds are found to be understudied. We highlight future research needs for utilizing the emerging data sets as a preview of a future state of the atmosphere in a world with targeted permanent reductions of emissions. Finally, we emphasize the need to account for the effects of meteorology, emission trends, and atmospheric chemistry when determining the lockdown effects on pollutant concentrations.

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“…On national scale, PM 2.5 shows less obvious diurnal patterns throughout the day. This may be due low 24-h average concentration where the daily means exhibit values lower than 30 µg m -3 in all settings (Chen et al, 2020). The peaks for NO 2 , CO, and SO 2 concentrations were distributed in the morning starting at 8 am which was correlated to morning traffic rush hours (Afroz et al, 2003;Azmi et al, 2010).…”

Section: Temporal and Spatial Variations Of Air Pollutantsmentioning

confidence: 92%

“…Sharma et al (2020) reported maximum reduction in PM 2.5 concentration in most regions in India due to lock down, whereas Dantas et al (2020) found that CO, NO 2 , and PM 10 concentrations reduced during lockdown in Rio de Janeiro, Brazil. A study by Chen et al (2020) found that PM 2.5 , PM 10 , SO 2 , NO 2 and CO concentrations during lockdown period in 366 urban area in mainland China fell as much as 14%, 15%, 12%, 16%, and 12% respectively from the previous year level. A similar decreased was also reported in East China in first quarter of 2020 with highest reduction of CO and NO 2 were 20% and 30% respectively compared to first quarter of 2019 due to reduction in human activity, transport restriction, and commercial demand .…”

Section: Introductionmentioning

confidence: 98%

Spatiotemporal Variations and Contributing Factors of Air Pollutant Concentrations in Malaysia during Movement Control Order due to Pandemic COVID-19

Ash’aari

Aris

Ezani

et al. 2020

Aerosol Air Qual. Res.

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The restriction of daily and economic-related activities due to COVID-19 pandemic via lockdown order has been reported to improve air quality. This study evaluated temporal and spatial variations of four major air pollutant concentrations across Malaysia before (March 4, 2020-March 17, 2020) and during the implementation of different phases of Movement Control Order (MCO) (March 18, 2020-May 12, 2020) from 65 official regulatory air quality stations. Results showed that restriction in daily and economic activities has remarkably reduced the air quality in all suburban , urban, and industrial settings with relatively small contributions from meteorological conditions. Overall, compared to before MCO, average concentrations of PM 2.5 , CO, and NO 2 reduced by 23.1%, 21.74%, and 54.0%, respectively, while that of SO 2 was constant. The highest reduction of PM 2.5 , CO, and NO 2 were observed in stations located in urban setting, where 63% stations showed significant reduction (p < 0.05) for PM 2.5 and CO, while all stations showed significant reduction in NO 2 concentrations. It was also revealed that 70.5% stations recorded lower concentrations of PM 2.5 during MCO compared to before MCO, despite that high numbers of local hotspots were observed simultaneously from NASA's Moderate Resolution Imaging Spectroradiometer (MODIS). Spatial analysis showed that the northern part of Peninsular had the highest significant reduction of PM 2.5 , while the highest of NO 2 and CO reduction were found in stations located in the central region. All pollutants exhibit similar diurnal trends when compared between pre-and during MCO although significant lower readings were observed during MCO. This study gives confidence to regulatory body; the enforcement of strict air pollution prevention and control policies could help in reducing pollution.

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Influence of COVID-19 Event on Air Quality and their Association in Mainland China

Cited by 79 publications

References 22 publications

Changes in Air Quality during the COVID-19 Lockdown in Singapore and Associations with Human Mobility Trends

Changes in Air Quality during the COVID-19 Lockdown in Singapore and Associations with Human Mobility Trends

The global impacts of COVID-19 lockdowns on urban air pollution

Spatiotemporal Variations and Contributing Factors of Air Pollutant Concentrations in Malaysia during Movement Control Order due to Pandemic COVID-19

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