Long-term (2006–2015) variations and relations of multiple atmospheric pollutants based on multi-remote sensing data over the North China Plain

Si, Ying; Wang, Hongmei; Cai, Kun; Chen, Liangfu; Zhou, Zhicheng

doi:10.1016/j.envpol.2019.113323

Cited by 29 publications

(22 citation statements)

References 70 publications

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“…In the case of NO2, multi-instrument analyses, which extend the observational record beyond the lifetime of a single instrument, depict a consistent regional picture of NO2 trends in China since 1996 (Geddes et al, 2016;Georgoulias et al, 2019;Xu et al, 2020). Column totals show an increasing trend during the first part of the satellite record, but this trend is reversed sometime between 2010 and 2014 (Georgoulias et al, 2019;Krotkov et al, 2016;Lin et al, 2019;Xu et al, 2020;Si et al, 2019;Shah et al, 2020). The trend reversal has been attributed to a combination of emission control measures (Zheng et al, 2018a) and variations in economic growth (Krotkov et al, 2016).…”

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confidence: 88%

Changes in satellite retrievals of atmospheric composition over eastern China during the 2020 COVID-19 lockdowns

Field

Hickman

Geogdzhayev

et al. 2020

Preprint

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Abstract. We examined daily Level-3 satellite retrievals of AIRS CO, OMI SO2 and NO2, and MODIS AOD over eastern China to understand how COVID-19 lockdowns affected atmospheric composition, taking into account trends that have occurred since 2005. Over central east China during the January 23–April 8 lockdown window, CO in 2020 was 12 % lower than the 2005–2019 mean, but only 2 % lower than what would be expected given the decreasing CO trend over that period. Similarly for AOD, 2020 was 30 % lower than the 2011–2019 mean, but not distinct from what would be expected from the trend. NO2 in 2020 was 43 % lower than the 2011–2019 mean, but only 17 % lower than what would be expected given the trend over that period. Over southern China, 2020 NO2 was not significantly different from anticipated, and CO and AOD were significantly higher that what would be expected, which we suggest was partly because of an active fire season in neighbouring countries. Over east central and southern China, SO2 was higher than expected, but the magnitude depended strongly on how daily regional values were calculated from individual retrievals. Future work over China, or other regions, needs to take these trends into account in order to separate the effects of COVID-19 on air quality from recent trends, or from variability in other sources.

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confidence: 88%

Changes in satellite retrievals of atmospheric composition over eastern China during the 2020 COVID-19 lockdowns

Field

Hickman

Geogdzhayev

et al. 2020

Preprint

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“…The spatial and temporal variations of satellite AOD, SO2, and NO2 reveal dramatic changes of anthropogenic pollutants in central China and their emission levels. OMI NO2 (~15 × 10 15 molecules cm −2 ) and SO2 (~0.5 DU) in the hotspot of Wuhan in central China is much lower than the high concentrations of NO2 (~20 × 10 15 molecules cm −2 ) and SO2 (~1.0 DU) in northern China [15,16]. Unlike the concentrated air pollution in northern China, pollution hotspots in central China have smaller scales and larger spatial variations.…”

Section: Discussionmentioning

confidence: 90%

Section: Spatial and Temporal Distribution Of Particle Pollution In 2mentioning

confidence: 99%

“…As shown in numerous studies, annual or seasonal mean maps of satellite AOD is usually used to denote particle pollution [19,33]. Different from the consistent distribution between gaseous precursors (NO2 and SO2) and AOD in northern China [15], the hotspots of gaseous pollutants and particles in central China are concentrated in completely different spatial locations of central China. Although sulfate and nitrate only account for at most about half of PM2.5 in major cities of China [11], anthropogenic emissions of SO2 and NOx have a much larger amount than organic Carbon (OC) and black Carbon (BC) [31].…”

Section: Spatial and Temporal Distribution Of Particle Pollution In 2mentioning

confidence: 99%

“…The heavy air pollution in China has drawn the attention of numerous observational studies from various perspectives. Besides ground-based measurements and chemistry model simulations, satellite studies have greatly renewed knowledge concerning spatial distribution of air pollution hotspots and variations of their major emissions in northern China [14][15][16], the Yangtze River Delta (YRD) [17], and Pearl River Delta (PRD) [18]. However, previous studies mostly focused on economically developed regions with extensive urban agglomeration.…”

Section: Introductionmentioning

confidence: 99%

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Long-Term (2005–2017) View of Atmospheric Pollutants in Central China Using Multiple Satellite Observations

Mei

Chen

et al. 2020

Remote Sensing

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The air quality in China has experienced dramatic changes during the last few decades. To improve understanding of distribution, variations, and main influence factors of air pollution in central China, long-term multiple satellite observations from moderate resolution imaging spectroradiometer (MODIS) and ozone monitoring instrument (OMI) are used to characterize particle pollution and their primary gaseous precursors, sulfur dioxide (SO2), and nitrogen dioxide (NO2) in Hubei province during 2005–2017. Unlike other regions in eastern China, particle and gaseous pollutants exhibit distinct spatial and temporal patterns in central China due to differences in emission sources and control measures. OMI SO2 of the whole Hubei region reached the highest value of ~0.2 Dobson unit (DU) in 2007 and then declined by more than 90% to near background levels. By contrast, OMI NO2 grew from ~3.2 to 5.9 × 1015 molecules cm−2 during 2005–2011 and deceased to ~3.9 × 1015 molecules cm−2 in 2017. Unlike the steadily declining SO2, variations of OMI NO2 flattened out in 2016 and increased ~0.5 × 1015 molecules cm−2 during 2017. As result, MODIS AOD at 550 nm increased from 0.55 to the peak value of 0.7 during 2005–2011 and then decreased continuously to 0.38 by 2017. MODIS AOD and OMI SO2 has a high correlation (R > 0.8), indicating that annual variations of SO2 can explain most changes of AOD. The air pollution in central China has notable seasonal variations, which is heaviest in winter and light in summer. While air quality in eastern Hubei is dominated by gaseous pollution such as O3 and NOx, particle pollutants are mainly concentrated in central Hubei. The high consistency with ground measurements demonstrates that satellite observation can well capture variations of air pollution in regional scales. The increasing ozone (O3) and NO2 since 2016 suggests that more control measures should be made to reduce O3-related emissions. To improve the air quality in regional scale, it is necessary to monitor the dynamic emission sources with satellite observations at a finer resolution.

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Comparison of PM2.5 and CO2 Concentrations in Large Cities of China during the COVID-19 Lockdown

Liu

Huang

et al. 2022

Adv. Atmos. Sci.

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Estimating the impacts on PM 2.5 pollution and CO 2 emissions by human activities in different urban regions is important for developing efficient policies. In early 2020, China implemented a lockdown policy to contain the spread of COVID-19, resulting in a significant reduction of human activities. This event presents a convenient opportunity to study the impact of human activities in the transportation and industrial sectors on air pollution. Here, we investigate the variations in air quality attributed to the COVID-19 lockdown policy in the megacities of China by combining in-situ environmental and meteorological datasets, the Suomi-NPP/VIIRS and the CO 2 emissions from the Carbon Monitor project. Our study shows that PM 2.5 concentrations in the spring of 2020 decreased by 41.87% in the Yangtze River Delta (YRD) and 43.30% in the Pearl River Delta (PRD), respectively, owing to the significant shutdown of traffic and manufacturing industries. However, PM 2.5 concentrations in the Beijing-Tianjin-Hebei (BTH) region only decreased by 2.01% because the energy and steel industries were not fully paused. In addition, unfavorable weather conditions contributed to further increases in the PM 2.5 concentration. Furthermore, CO 2 concentrations were not significantly affected in China during the short-term emission reduction, despite a 19.52% reduction in CO 2 emissions compared to the same period in 2019. Our results suggest that concerted efforts from different emission sectors and effective long-term emission reduction strategies are necessary to control air pollution and CO 2 emissions. Electronic supplementary material Supplementary material is available in the online version of this article at 10.1007/s00376-021-1281-x.

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Long-term (2006–2015) variations and relations of multiple atmospheric pollutants based on multi-remote sensing data over the North China Plain

Cited by 29 publications

References 70 publications

Changes in satellite retrievals of atmospheric composition over eastern China during the 2020 COVID-19 lockdowns

Changes in satellite retrievals of atmospheric composition over eastern China during the 2020 COVID-19 lockdowns

Long-Term (2005–2017) View of Atmospheric Pollutants in Central China Using Multiple Satellite Observations

Comparison of PM2.5 and CO2 Concentrations in Large Cities of China during the COVID-19 Lockdown

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