Article
Environmental Sciences
Dilek Savas, Gaelle Dufour, Adriana Coman, Guillaume Siour, Audrey Fortems-Cheiney, Gregoire Broquet, Isabelle Pison, Antoine Berchet, Bertrand Bessagnet
Summary: The Chinese government introduced regulations in 2011 to control emissions and reduce NOx pollutants. This study estimates anthropogenic NOx emissions in Eastern China in 2015 and 2019 using different approaches. The results show a slight global decrease in NOx emissions, mainly in urban and industrial areas. Our estimates suggest that the reduction in emissions between 2010 and 2015 may be underestimated in the most polluted regions, while MEIC inventory likely overestimates emissions in certain regions compared to 2010.
Article
Geosciences, Multidisciplinary
Vitali E. Fioletov, Chris A. McLinden, Debora Griffin, Ihab Abboud, Nickolay Krotkov, Peter J. T. Leonard, Can Li, Joanna Joiner, Nicolas Theys, Simon Carn
Summary: Measurements of sulfur dioxide (SO2) from three satellite spectrometers, OMI, OMPS, and TROPOMI, were used to update and extend a global catalogue of large SO2 emission sources. The catalogue includes 759 continuously emitting point sources from volcanoes, power plants, smelters, and sources related to the oil and gas industry. The data show a decline in global SO2 emissions between 2005 and 2021, with emissions remaining stable in recent years.
EARTH SYSTEM SCIENCE DATA
(2023)
Article
Engineering, Environmental
Kanishka B. Narayan, Steven J. Smith, Vitali E. Fioletov, Chris A. McLinden
Summary: We conducted a comprehensive evaluation of errors in anthropogenic SO2 emission estimates from NASA's OMI point source catalog. We found relatively low errors in aggregate, but substantial errors for individual sources in any given year. The errors are not random over time and there can be consistently positive or negative biases for individual sources. The OMI-based SO2 emissions are accurate in aggregate but must be interpreted cautiously at the individual source level.
ENVIRONMENTAL SCIENCE & TECHNOLOGY
(2023)
Article
Environmental Sciences
Daniel L. Goldberg, Susan C. Anenberg, Zifeng Lu, David G. Streets, Lok N. Lamsal, Erin E. McDuffie, Steven J. Smith
Summary: This study uses satellite remote sensing to estimate urban nitrogen oxide emissions for 80 global cities between 2005 and 2019, revealing a larger downward trend compared to inventory reports, especially in Africa, China, India, Latin America, and the Middle East.
ENVIRONMENTAL RESEARCH LETTERS
(2021)
Article
Environmental Sciences
Dmitry V. Ionov, Maria V. Makarova, Vladimir S. Kostsov, Stefani C. Foka
Summary: This study estimates the NOx emissions of the metropolitan area of St. Petersburg using experimental and simulation methods. The contribution of urban thermal power plants to the total emissions is also determined.
ATMOSPHERIC POLLUTION RESEARCH
(2022)
Article
Meteorology & Atmospheric Sciences
Jia Jung, Yunsoo Choi, Amir H. Souri, Seyedali Mousavinezhad, Alqamah Sayeed, Kyunghwa Lee
Summary: This study quantifies the impact of transported air pollutants on local air quality using inverse modeling technique and satellite data. The results show that using satellite-constrained emissions data can significantly improve model performance and reveal the contributions of emissions from neighboring regions to local air quality.
JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES
(2022)
Article
Environmental Sciences
Ruijun Dang, Hong Liao, Yu Fu
Summary: The study used the GEOS-Chem model to investigate the factors driving the summer surface ozone trend in China during the period of 2012-2017, showing that both anthropogenic emissions and meteorological changes contributed to the increases in O3 concentrations in the North China Plain and Yangtze River Delta. In particular, meteorological factors played a more significant role in driving O3 increases in the Yangtze River Delta.
SCIENCE OF THE TOTAL ENVIRONMENT
(2021)
Article
Engineering, Environmental
Jia Xing, Siwei Li, Shuxin Zheng, Chang Liu, Xiaochun Wang, Lin Huang, Ge Song, Yihan He, Shuxiao Wang, Shovan Kumar Sahu, Jia Zhang, Jiang Bian, Yun Zhu, Tie-Yan Liu, Jiming Hao
Summary: In this study, a novel machine-learning method based on a physically informed variational autoencoder (VAE) emission predictor was proposed to infer NOx emissions from satellite-retrieved surface NO2 concentrations. By training a neural network with a chemical transport model, the computational burden can be significantly reduced, enabling the VAE emission predictor to provide timely estimates of posterior emissions. The results showed that the VAE emission predictor successfully corrected the underestimation and overestimation of NOx emissions in different areas, leading to improved accuracy. Sensitivity analysis further confirmed the importance of NO2 concentration and planetary boundary layer (PBL) height in estimating NOx emissions.
ENVIRONMENTAL SCIENCE & TECHNOLOGY
(2022)
Article
Environmental Sciences
Yi Wang, Cui Ge, Lorena Castro Garcia, G. Darrel Jenerette, Patty Y. Oikawa, Jun Wang
Summary: The study investigates the impact of soil and lightning NOx emissions on the trend of OMI NO2, finding that improvements in estimating soil NOx emissions have led to a slowdown in the reduction of total NOx emissions. With background emissions becoming relatively larger and inter-annual variations uncertain, relying solely on NO2 VCDs is insufficient to discern trends in anthropogenic emissions.
ENVIRONMENTAL RESEARCH LETTERS
(2021)
Article
Environmental Sciences
Ke Che, Zhaonan Cai, Yi Liu, Lin Wu, Dongxu Yang, Yichen Chen, Xiaoyan Meng, Minqiang Zhou, Jing Wang, Lu Yao, Pucai Wang
Summary: The study estimated CO2 emissions in the winter from the Beijing region of China using differential ground-based observations and simulated enhancements based on different emission inventories. The posterior emissions were obtained through a Lagrangian inversion framework using Bayesian theory. The differences in transport errors and spatially uneven corrections in Beijing were identified as the main reasons for the discrepancies in the emission estimates.
ENVIRONMENTAL RESEARCH LETTERS
(2022)
Article
Engineering, Environmental
Gary A. Bishop, Molly J. Haugen, Brian C. McDonald, Adam M. Boies
Summary: There have been few studies on wintertime NOx emissions from heavy-duty vehicles (HDVs) in the United States, and fleet characterization to identify the cause has been lacking. In this study, wintertime measurements of NOx emission factors were collected from 1591 HDVs at a Utah Port of Entry in December 2020, showing that NOx emission factors for 2011 and newer chassis model year HDVs are significantly higher than those for 2017 spring measurements from California. The newest chassis model year HDVs (2017-2021) have similar NOx emission factors, indicating no significant deterioration over the 5 year period. The study also estimated that ambient temperature increase has a limited impact on NOx emissions in the newer HDVs, while the 2011-2013 chassis model year vehicles have significantly higher NOx emissions and have lost their NOx control capabilities within 8 years. The MOVES3 modeling of the Utah fleet underestimated mean NOx emissions, but including a larger fraction of high-emitting glider kit trucks in the estimates improved the accuracy.
ENVIRONMENTAL SCIENCE & TECHNOLOGY
(2022)
Article
Geosciences, Multidisciplinary
Wenjian Hua, Minhua Qin, Aiguo Dai, Liming Zhou, Haishan Chen, Wanxin Zhang
Summary: The recent summer surface air temperature changes over densely populated Eurasia show a non-uniform pattern, with amplified warming over Europe and East Asia but weak warming over Central Asia, forming a wave train-like structure. External forcing may play a significant role in the SAT multidecadal variations over Europe-west Asia and EA, while internal variations in the Atlantic and Pacific oceans primarily influence the recent SAT over CA. Forced SAT multidecadal variations over Eurasia are mainly attributed to changes in greenhouse gases and aerosols according to large ensemble model simulations.
GEOPHYSICAL RESEARCH LETTERS
(2021)
Article
Multidisciplinary Sciences
Shuchita Srivastava, Asfa Siddiqui, D. Mitra, Prakash Chauhan
Summary: The nationwide lockdown in India led to a significant reduction in nitrogen dioxide levels across the country, particularly in the Indo Gangetic Plain, eastern and southern regions. However, the western region showed a slight increase, possibly due to polluted air transport from the Middle East and Pakistan, as well as higher biomass burning activity in 2020.
Article
Environmental Sciences
Karol Szymankiewicz, Jacek W. Kaminski, Joanna Struzewska
Summary: The research aimed to adjust emission inventories using observed tropospheric NO2 columns from satellite instruments, improving the accuracy of the chemical weather model GEM-AQ. The spatial distribution of NO2 was found to be correlated with major anthropogenic sources. The proposed method showed potential for correcting emission estimates and led to significant improvements in modelling results.
Article
Multidisciplinary Sciences
Karn Vohra, Eloise A. Marais, William J. Bloss, Joel Schwartz, Loretta J. Mickley, Martin Van Damme, Lieven Clarisse, Pierre-F Coheur
Summary: The study reveals that many fast-growing tropical cities are experiencing worsening air pollution mainly due to emerging anthropogenic sources, rather than traditional biomass burning, posing a serious health threat to urban residents. Urgent regulatory action is needed to address this issue.
Article
Environmental Sciences
Xiangyunong Cao, Dasa Gu, Xin Li, Ka Fung Leung, Hao Sun, Yuchen Mai, Wai Ming Chan, Zhenxing Liang
Summary: This study conducted an eight-month air sampling in a coastal site in Hong Kong and investigated seventeen halocarbon species. The results showed lower enhancements for regulated CFCs and CCl4, indicating progress in implementing the Montreal Protocol. Non-regulated halocarbons from China were found to have high enhancement values. Source apportionment analysis identified six emission sectors contributing to the measured halocarbons.
SCIENCE OF THE TOTAL ENVIRONMENT
(2023)
Article
Computer Science, Information Systems
Yuan Liu, Chuang Zhang, Yu Yan, Xin Zhou, Zhihong Tian, Jie Zhang
Summary: This study proposes a semi-centralized trust management system architecture based on blockchain to support various applications and services with massive IoT devices. The IoT devices are centralized organized by cloud servers, which maintain a rating data ledger within each domain using the proposed rotation-based consensus protocol. A computational trust model is proposed to identify and mitigate the influence of malicious devices by aggregating direct and indirect trust information. Simulation experiments and comparisons with classical models demonstrate the effectiveness of the proposed trust model in identifying and mitigating the influence of malicious devices.
IEEE TRANSACTIONS ON SERVICES COMPUTING
(2023)
Article
Environmental Sciences
Srijana Lama, Sander Houweling, K. Folkert Boersma, Ilse Aben, Hugo A. C. Denier van der Gon, Maarten C. Krol
Summary: Movement restrictions during the 2020 lockdowns provide a unique opportunity to study the sensitivity of urban photochemistry to emission reductions and test air quality models. This study uses TROPOMI to analyze nitrogen dioxide and carbon monoxide ratios in urban areas during COVID-19 lockdowns and compares them to the previous year. The results show reductions in NOx lifetime during calm days in all six cities studied. Windy days also showed some reductions in tau(NOx) in certain cities. The use of ground-based measurements and a model further validated the TROPOMI results. This study demonstrates the usefulness of TROPOMI in studying urban photochemistry and detecting changes in photochemical lifetimes.
ATMOSPHERIC ENVIRONMENT
(2023)
Article
Environmental Sciences
Yuxi Sun, Yuchen Mai, Nirmal Kumar Gali, Peter Brimblecombe, Peter K. K. Louie, Yiu-Yuen Tsang, Zhi Ning, Dasa Gu
Summary: This study proposes a new method of using helicopters as platforms for real-time monitoring of air pollutants and routine canister sampling to enhance our understanding of air pollution in the Greater Bay Area. By employing this method, the local spatial and vertical distribution of various air pollutants in Hong Kong can be obtained within hours. The findings of the investigation show higher concentrations of O3 and PM2.5 in the northern region on days with episodic pollution, while urban areas exhibited elevated levels of NO2 and CO concentration.
ATMOSPHERIC ENVIRONMENT
(2023)
Article
Environmental Sciences
Xin Li, Dasa Gu, Tilman Leo Hohenberger, Yik Him Fung, Jimmy C. H. Fung, Alexis K. H. Lau, Zhenxing Liang
Summary: This study develops a dynamic on-road emission inventory for Hong Kong, using traffic congestion index, traffic density model, and local emission factors. The results show higher emissions on weekdays and public transportation as the major emission sources.
ATMOSPHERIC ENVIRONMENT
(2023)
Article
Engineering, Environmental
Qianru Zhang, Yuhang Wang, Maodian Liu, Mingming Zheng, Lianxin Yuan, Junfeng Liu, Shu Tao, Xuejun Wang
Summary: Outdoor air pollution is responsible for millions of premature deaths worldwide every year. This study focuses on sulfate, a major component of particulate pollution, and investigates its size distribution and formation mechanisms. The researchers find that the observed size distribution of sulfate particles in winter in China cannot be explained by classical gaseous and aqueous phase formation mechanisms. Instead, they propose that in-source formation, where particles rapidly grow through the condensation of sulfuric acid, is the main source of micron-sized sulfate particles in China during winter. This finding highlights the importance of considering aerosol size distribution for accurately assessing the impacts of inorganic aerosols on radiative forcing and human health.
ENVIRONMENTAL SCIENCE & TECHNOLOGY
(2023)
Article
Multidisciplinary Sciences
Hui Li, Bo Zheng, Philippe Ciais, K. Folkert Boersma, T. Christoph V. W. Riess, Randall V. Martin, Gregoire Broquet, A. Ronald Van Der, Haiyan Li, Chaopeng Hong, Yu Lei, Yawen Kong, Qiang Zhang, Kebin He
Summary: The emergence of the Omicron variant in 2022 has caused a larger decline in China's CO2 emissions compared to the first wave in 2020. Satellite observations indicate a 15% decrease, equivalent to 244.3 million metric tons of CO2, during the 2022 lockdown, hindering China's emissions rebound.
Article
Geosciences, Multidisciplinary
Zhenxin Liu, Yuanhao Chen, Yuhang Wang, Cheng Liu, Shuhua Liu, Hong Liao
Summary: The heterogeneity of urban canopy leads to the spatial inhomogeneity of wind field in urban street canyons. Most current urban canopy models do not consider this heterogeneity, resulting in large discrepancies between simulated and observed wind speeds. In this study, a parameterization scheme called IWSUS is developed to better characterize the heterogeneity of the urban canopy. Validation results show that IWSUS performs better than the widely used exp-log law.
GEOSCIENTIFIC MODEL DEVELOPMENT
(2023)
Article
Computer Science, Artificial Intelligence
Yixin Liu, Ming Jin, Shirui Pan, Chuan Zhou, Yu Zheng, Feng Xia, Philip S. Yu
Summary: Deep learning on graphs is a rapidly growing field, however, most works have focused on (semi-) supervised learning, leading to issues such as heavy label reliance and insufficient generalization. To address these problems, self-supervised learning (SSL) has emerged as a promising learning paradigm for graph data. In this review, we provide a comprehensive overview of existing SSL approaches for graphs, including a unified framework, different categories of approaches, applications, datasets, benchmarks, and challenges for future research in this field.
IEEE TRANSACTIONS ON KNOWLEDGE AND DATA ENGINEERING
(2023)
Article
Environmental Sciences
Chandan Sarangi, Yun Qian, L. Ruby Leung, Yang Zhang, Yufei Zou, Yuhang Wang
Summary: Anthropogenic contribution to PM2.5 concentrations is decreasing in North America, while the pollution caused by wildfires is increasing, especially in the eastern US. Based on simulations, it is projected that by the mid-21st century, wildfire-induced PM2.5 concentrations will double compared to the present, with a significant impact in the eastern US. This is attributed to the transportation of smoke from increased wildfires in North America and the positive climatic feedback on PM2.5.
ATMOSPHERIC CHEMISTRY AND PHYSICS
(2023)
Article
Geosciences, Multidisciplinary
John Douros, Henk Eskes, Jos van Geffen, K. Folkert Boersma, Steven Compernolle, Gaia Pinardi, Anne-Marlene Blechschmidt, Vincent-Henri Peuch, Augustin Colette, Pepijn Veefkind
Summary: This article introduces the application of Sentinel-5P TROPOspheric Monitoring Instrument (TROPOMI) and Copernicus Atmosphere Monitoring Service (CAMS) in atmospheric quality forecasting. By comparing the observations from TROPOMI with the forecasts from CAMS, it is found that they agree well in summer but show significant discrepancies in winter. The article also discusses the use of profile information from the CAMS configuration of the ECMWF global model and the replacement of global configuration with regional configuration to improve the TROPOMI data product.
GEOSCIENTIFIC MODEL DEVELOPMENT
(2023)
Article
Environmental Sciences
Viral Shah, Daniel J. Jacob, Ruijun Dang, Lok N. Lamsal, Sarah A. Strode, Stephen D. Steenrod, K. Folkert Boersma, Sebastian D. Eastham, Thibaud M. Fritz, Chelsea Thompson, Jeff Peischl, Ilann Bourgeois, Ilana B. Pollack, Benjamin A. Nault, Ronald C. Cohen, Pedro Campuzano-Jost, Jose L. Jimenez, Simone T. Andersen, Lucy J. Carpenter, Tomas Sherwen, Mat J. Evans
Summary: Satellite-based retrievals of tropospheric NO2 columns are widely used to infer NOx emissions. These retrievals rely on model information for the vertical distribution of NO2. Free tropospheric background above 2 km is important for these retrievals and has a significant impact on tropospheric OH and ozone concentrations.
ATMOSPHERIC CHEMISTRY AND PHYSICS
(2023)
Article
Environmental Sciences
Qianqian Zhang, K. Folkert Boersma, Bin Zhao, Henk Eskes, Cuihong Chen, Haotian Zheng, Xingying Zhang
Summary: We present a new top-down method, an improved superposition column model, to estimate daily NOx and CO2 emissions from Wuhan, China. We employed the latest TROPOMI NO2 data and OCO-2 observed CO2 mixing ratio. Our estimated emissions were verified against bottom-up inventories and can provide real-time information on air quality and climate change.
ATMOSPHERIC CHEMISTRY AND PHYSICS
(2023)
Article
Engineering, Environmental
Yuhang Wang, Shengjun Xi, Fanghe Zhao, Lewis Gregory Huey, Tong Zhu
Summary: Nighttime oxidation by nitrate radicals has significant implications for aerosol formation, climate, and human health. While a previous study found an increase in nitrate production in China from 2014 to 2019, contrasting trends were observed in the U.S. and Europe. However, our analysis of observational data from 2014 to 2022 shows that nitrate production in China did not increase during this period, primarily due to a continuous decrease in the NO2/O-3 ratio. Interestingly, our findings also suggest the potential for a surge in urban nighttime nitrate radicals despite emission reduction efforts.
ENVIRONMENTAL SCIENCE & TECHNOLOGY
(2023)
Article
Meteorology & Atmospheric Sciences
Wei Feng, Xinyue Wang, Zhijuan Shao, Hong Liao, Yuhang Wang, Mingjie Xie
Summary: This study analyzed PM2.5 samples collected in northern Nanjing to understand the diurnal variations in PM2.5 composition and aerosol extract absorption. The results showed that biomass burning and secondary formation were the major sources of brown carbon in this region.
JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES
(2023)
