| 1 | Satellite UV-Vis spectroscopy:implications for air quality trends and their driving forces in China during 2005-2017显示文摘Abundances of a range of air pollutants can be inferred from satellite UV-Vis spectroscopy measurements by using the unique absorption signatures of gas species.Here,we implemented several spectral fitting methods to retrieve tropospheric NO_(2),SO_(2),and HCHO from the ozone monitoring instrument(OMI),with radiative simulations providing necessary information on the interactions of scattered solar light within the atmosphere.We analyzed the spatial distribution and temporal trends of satellite-observed air pollutants over eastern China during 2005-2017,especially in heavily polluted regions.We found significant decreasing trends in NO_(2) and SO_(2) since 2011 over most regions,despite varying temporal features and turning points.In contrast,an overall increasing trend was identified for tropospheric HCHO over these regions in recent years.Furthermore,generalized additive models were implemented to understand the driving forces of air quality trends in China and assess the effectiveness of emission controls.Our results indicated that although meteorological parameters,such as wind,water vapor,solar radiation and temperature,mainly dominated the day-to-day and seasonal fluctuations in air pollutants,anthropogenic emissions played a unique role in the long-term variation in the ambient concentrations of NO_(2),SO_(2),and HCHO in the past 13 years.Generally,recent declines in NO_(2) and SO_(2) could be attributed to emission reductions due to effective air quality policies,and the opposite trends in HCHO may urge the need to control anthropogenic volatile organic compound(VOC)emissions. | Chengxin Zhang Cheng Liu Qihou Hu Zhaonan Cai Wenjing Su Congzi Xia Yizhi Zhu Siwen Wang Jianguo Liu | 2019 | Light(Science & Applications)2019，8，1： | 11 |
| 2 | First Chinese ultraviolet-visible hyperspectral satellite instrument implicating global air quality during the COVID-19 pandemic in early 2020显示文摘In response to the COVID-19 pandemic,governments worldwide imposed lockdown measures in early 2020,resulting in notable reductions in air pollutant emissions.The changes in air quality during the pandemic have been investigated in numerous studies via satellite observations.Nevertheless,no relevant research has been gathered using Chinese satellite instruments,because the poor spectral quality makes it extremely difficult to retrieve data from the spectra of the Environmental Trace Gases Monitoring Instrument(EMI),the first Chinese satellite-based ultraviolet–visible spectrometer monitoring air pollutants.However,through a series of remote sensing algorithm optimizations from spectral calibration to retrieval,we successfully retrieved global gaseous pollutants,such as nitrogen dioxide(NO2),sulfur dioxide(SO2),and formaldehyde(HCHO),from EMI during the pandemic.The abrupt drop in NO2 successfully captured the time for each city when effective measures were implemented to prevent the spread of the pandemic,for example,in January 2020 in Chinese cities,February in Seoul,and March in Tokyo and various cities across Europe and America.Furthermore,significant decreases in HCHO in Wuhan,Shanghai,Guangzhou,and Seoul indicated that the majority of volatile organic compounds(VOCs)emissions were anthropogenic.Contrastingly,the lack of evident reduction in Beijing and New Delhi suggested dominant natural sources of VOCs.By comparing the relative variation of NO2 to gross domestic product(GDP),we found that the COVID-19 pandemic had more influence on the secondary industry in China,while on the primary and tertiary industries in Korea and the countries across Europe and America. | Cheng Liu Qihou Hu Chengxin Zhang Congzi Xia Hao Yin Wenjing Su Xiaohan Wang Yizhou Xu Zhiguo Zhang | 2022 | Light(Science & Applications)2022，11，2： | 1 |
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