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Parametric MELCOR 2.2 sensitivity and uncertainty study with a focus on aerosols based on Ph′ebus test FPT1

PROGRESS IN NUCLEAR ENERGY 2023年 158卷

作者： Malicki, Mateusz Lind, Terttaliisa Paul Scherrer Inst Forschungsstr 111 CH-5232 Villigen Switzerland

The Phe ' bus test FPT-1 was carried out to investigate the fission product release, transportation, and distribution in the reactor coolant system and the simulated containment during a severe accident. The test was divided into three phases: the core degradation, aerosol transport, and containment phenomena. In this work, a parametric sensitivity and uncertainty analysis of the two first phases, i.e., core degradation and aerosol transport, is con-ducted with the focus on aerosol *** study was done in a frame of WP4 of the European MUSA project whose main objective is to develop a methodology for severe accident uncertainty *** to the wide scope of the MUSA project, this study focuses not only on the UQ analysis but also on the parametric dependency and data interpretation. The main subject was investigating the uncertainty of the MELCOR 2.2 aerosol models and the relation between the chosen parameters as well as evaluating the usability of essential analytical tools available for such *** calculations were carried out using the integral severe accident code MELCOR2.2 and the generic input deck of the FPT-1 experiment. The uncertainty quantification tool DAKOTA was used as a statistical tool. It was coupled with MELCOR within the SNAP *** uncertain parameters related with the aerosol release and transport were investigated. Two figures of merit were chosen to be the amount of deposition of Cs in the reactor coolant circuit, and the mass of air-borne aerosol in the containment. Preliminary analysis showed a significant correlation between the aerosol dynamic and agglomeration shape factors, density and minimum aerosol diameter with both FOMs. In addition to the standard uncertainty analysis, five MELCOR/DAKOTA UQ sensitivity calculations with modified parameters were performed and analyzed. Additionally, the impact of the parameters was investigated by excluding the most correlated ones from the analysis. The results con

关键词： Uncertainty study aerosols Severe accident

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Characteristics and optical properties of atmospheric aerosols based on long-term AERONET investigations in an urban environment of Pakistan

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SCIENTIFIC REPORTS 2024年第1期14卷 1-11页

作者： Zeb, Bahadar Alam, Khan Khan, Rehana Ditta, Allah Iqbal, Rashid Elsadek, Mohamed Farouk Raza, Ahsan Elshikh, Mohamed Soliman Shaheed Benazir Bhutto Univ Dept Math Peshawar Khyber Pakhtunk Pakistan Univ Peshawar Dept Phys Peshawar Pakistan Higher Educ Coll Dept Phys Govt Khyber Pakhtunkhwa Peshawar Pakistan Shaheed Benazir Bhutto Univ Sheringal Dept Environm Sci Sheringal 18000 Khyber Pakhtunk Pakistan Univ Western Australia Sch Biol Sci 35 Stirling Highway Perth WA 6009 Australia Islamia Univ Bahawalpur Dept Agron Bahawalpur 63100 Pakistan King Saud Univ Coll Sci Dept Biochem POB 2455 Riyadh 11451 Saudi Arabia Univ Bonn Inst Crop Sci & Resource Conservat INRES Bonn Germany King Saud Univ Coll Sci Dept Bot & Microbiol Riyadh 11451 Saudi Arabia Leibniz Ctr Agr Landscape Res ZALF Eberswalder Str 84 D-15374 Muncheberg Germany

Radiative balance, local climate, and human health are all significantly influenced by aerosol. Recent severe air pollution over Lahore, a city in Pakistan calls for more thorough research to determine the negative impacts brought on by too many aerosols. To study regional aerosol characteristics and their differences from various aspects, in-depth and long-term (2007-2020) investigations of the columnar aerosol properties over the urban environment of Lahore were carried out by using AERONET data. The Aerosol Optical Depth (AOD400) and Angstrom Exponent (AE400-870) vary from low values of 0.10 to a maximum value of 4.51 and from 0.03 to 1.81, respectively. The huge differences in the amount of AOD440 as well as AE440-870 show the large fluctuation of aerosol classes because of various sources of their emission. During the autumn and winter seasons, the decreasing trend of the optical parameters of aerosols like Single Scattering Albedo (SSA) and Asymmetry Parameter (ASY) with increasing wavelength from 675 to 1020 nm indicates the dominance of light-absorbing aerosols (biomass burning (BB) and industrial/urban (UI). Due to the long-distance dust movement during spring, summer, and autumn, coarse mode particles predominated in Lahore during the study period. Dust type (DD) aerosols are found to be the dominant one during spring (46.92%), summer (54.31%), and autumn (57.46%) while urban industry (BB/UI) was dominant during the winter season (53.21%). During each season, the clean continental (CC) aerosols are found to be in negligible amounts, indicating terrible air quality in Lahore City. The present research work fills up the study gap in the optical properties of aerosols in Lahore and will help us understand more fully how local aerosol fluctuation affects regional climate change over the urban environment of Lahore.

关键词： AERONET aerosols Metropolitan Clean continental Aerosol optical depth Angstrom exponent

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Role of Sea Fog Over the Yellow Sea on Air Quality With the Direct Effect of aerosols

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JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES 2021年第5期126卷 e2020JD033498-e2020JD033498页

作者： Jung, Jia Choi, Yunsoo Wong, David C. Nelson, Delaney Lee, Sojin Univ Houston Dept Earth & Atmospher Sci Houston TX 77004 USA US EPA Res Triangle Pk NC 27711 USA Seoul Inst Dept Safety & Environm Res Seoul South Korea

In this study, we investigate the impact of sea fog over the Yellow Sea on air quality with the direct effect of aerosols for the entire year of 2016. Using the WRF-CMAQ two-way coupled model, we perform four model simulations with the up-to-date emission inventory over East Asia and dynamic chemical boundary conditions provided by hemispheric model simulations. During the spring of 2016, prevailing west-southwesterly winds and anticyclones caused the formation of a temperature inversion over the Yellow Sea, providing favorable conditions for the formation of fog. The inclusion of the direct effect of aerosols enhanced its strength. On foggy days, we find dominant changes of aerosols at an altitude of 150-200 m over the Yellow Sea resulted by the production through aqueous chemistry (similar to 12.36% and similar to 3.08% increases in sulfate and ammonium) and loss via the wet deposition process (similar to-3.79% decrease in nitrate);we also find stronger wet deposition of all species occurring in PBL. Stagnant conditions associated with reduced air temperature caused by the direct effect of aerosols enhanced aerosol chemistry, especially in coastal regions, and it exceeded the loss of nitrate. The transport of air pollutants affected by sea fog extended to a much broader region. Our findings show that the Yellow Sea acts as not only a path of long-range transport but also as a sink and source of air pollutants. Further study should investigate changes in the impact of sea fog on air quality in conjunction with changes in the concentrations of aerosols and the climate.

关键词： aerosols air quality direct effect sea fog WRF‐ CMAQ two‐ way Yellow Sea

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Assessment of long-term trends in chlorophyll-a and sea surface temperature in the Arabian Sea and their association with aerosols using remote sensing

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OCEAN & COASTAL MANAGEMENT 2023年第1期242卷

作者： Sun, Yunpeng Gao, Pengpeng Tariq, Salman Azhar, Ayesha ul Haq, Zia Mehmood, Usman Tianjin Univ Commerce Sch Econ Tianjin Peoples R China Univ Punjab Natl Ctr GIS & Space Applicat Ctr Remote Sensing Remote Sensing GIS & Climat Res Lab Lahore Pakistan Univ Punjab Dept Space Sci New Campus Lahore Pakistan Univ Management & Technol Lahore Pakistan

aerosols over the oceanic region significantly influence Earth's energy budget and climate change. Therefore, this study examines the spatiotemporal patterns of MODIS retrieved aerosol optical depth, sea surface temperature, Chlorophyll-a, Sea-WiFS retrieved aerosol optical depth, and MERRA-2 model dust mass concentrations over the Arabian Sea (4o N-26o N to 50o E- 78o E) during the period 2002-2020. The effects of dust aerosols on phytoplankton blooms using the Mann-Kendall and Theil Sen-slope are also analyzed in this study. An increase in aerosol optical depth (AOD) was observed within the latitudes of (4o N-26o N). The AOD shows an increasing trend at 13.4% per year over the Arabian Sea (AS). The highest value of Chl-a (-7 mgm 3) was observed along the coast of Pakistan, Iran, and Oman. Moreover, a negative correlation is found between AOD and sea surface temperature (SST) along the coast of Oman and Somalia, while a strong positive correlation (-0.99) is observed between AOD and Chlorophyll-a (Chl-a) along the coasts of Oman and Somalia.

关键词： aerosols Arabian sea AOD SST Remote sensing

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Surface-Enhanced Raman Spectroscopy for Environmental Monitoring of aerosols

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ACS OMEGA 2021年第15期6卷 10150-10159页

作者： Sivaprakasam, Vasanthi Hart, Matthew B. Naval Res Lab Washington DC 20375 USA

Surface-enhanced Raman spectroscopy (SERS) is conducted from single aerosol particles held in a linear electro-dynamic quadrupole trap. SERS measurements from two representative types of ambient aerosol particles, semi-liquid and solid aerosols, are demonstrated;aerosol composed of adenine where the metallic nanoparticles (MNPs) are volume distributed throughout the particle and aerosol composed of polystyrene latex (PSL) beads where the MNPs are surface coated. An enhancement factor > 10(6) is demonstrated from 5 mu m aerosols containing trace amounts of adenine (0.1% by mass), with a detection limit of 10(-8) M corresponding to 5 x 10(5) molecules (equivalent to 100 ag in mass or a 50 nm diameter sphere), and a ratio of 100 adenine molecules per Ag NP. SERS signal intensities are linear with particle adenine concentration up to a saturation point. Both the linearity and enhancement factor were confirmed by SERS measurements of adenine as bulk suspensions. The SERS spectra of adenine as bulk suspensions were explored as a function of excitation wavelength ranging from 400 to 800 nm. The two main Raman peaks of adenine at 738 and 1336 cm(-1) exhibit SERS maxima for excitation in the 450-500 nm range for commercially available 40 nm spherical Ag nanoparticles (NPs) used in this study, which shifts to longer wavelengths with the addition of NaCl. Shifts in SERS and spontaneous Raman shifts were observed between aqueous and dry adenine, in agreement with the literature, demonstrating the utility of SERS to possibly study water uptake of aerosols. SERS is measured from MNP surface-coated PSL beads with an enhancement factor of 30 for 5 mu m PSLs. Theoretical extrapolation demonstrates that the enhancement factor will increase for decreasing particle size with an estimated enhancement factor of 140 for 1 mu m PSLs.

关键词： Adenine Nanoparticles Raman spectroscopy aerosols Suspensions

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Machine Learning Techniques for Vertical Lidar-Based Detection, Characterization, and Classification of aerosols and Clouds: A Comprehensive Survey

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REMOTE SENSING 2023年第17期15卷 4318-4318页

作者： Lolli, Simone CNR Inst Methodol Environm Anal IMAA Contrada S Loja Snc I-85050 Tito PZ Italy

This survey presents an in-depth analysis of machine learning techniques applied to lidar observations for the detection of aerosol and cloud optical, geometrical, and microphysical properties. Lidar technology, with its ability to probe the atmosphere at very high spatial and temporal resolution and measure backscattered signals, has become an invaluable tool for studying these atmospheric components. However, the complexity and diversity of lidar technology requires advanced data processing and analysis methods, where machine learning has emerged as a powerful approach. This survey focuses on the application of various machine learning techniques, including supervised and unsupervised learning algorithms and deep learning models, to extract meaningful information from lidar observations. These techniques enable the detection, classification, and characterization of aerosols and clouds by leveraging the rich features contained in lidar signals. In this article, an overview of the different machine learning architectures and algorithms employed in the field is provided, highlighting their strengths, limitations, and potential applications. Additionally, this survey examines the impact of machine learning techniques on improving the accuracy, efficiency, and robustness of aerosol and cloud real-time detection from lidar observations. By synthesizing the existing literature and providing critical insights, this survey serves as a valuable resource for researchers, practitioners, and students interested in the application of machine learning techniques to lidar technology. It not only summarizes current state-of-the-art methods but also identifies emerging trends, open challenges, and future research directions, with the aim of fostering advancements in this rapidly evolving field.

关键词： lidar machine learning aerosols clouds rain boundary layer

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Tracking the Transport of SO2 and Sulphate aerosols from the Tonga Volcanic Eruption to South Africa

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ATMOSPHERE 2023年第10期14卷 1556-1556页

作者： Shikwambana, Lerato Sivakumar, Venkataraman Xongo, Kanya South African Natl Space Agcy Earth Observat Directorate ZA-0001 Pretoria South Africa Univ Witwatersrand Sch Geog Archaeol & Environm Studies ZA-2050 Johannesburg South Africa Univ KwaZulu Natal Sch Chem & Phys ZA-4041 Durban South Africa Univ KwaZulu Natal Natl Inst Theoret & Computat Sci ZA-4000 Durban South Africa

During a volcanic eruption, copious amounts of volcanic gas, aerosol droplets, and ash are released into the stratosphere, potentially impacting radiative feedback. One of the most significant volcanic gases emitted is sulphur dioxide, which can travel long distances and impact regions far from the source. This study aimed to investigate the transport of sulphur dioxide and sulphate aerosols from the Tonga volcanic eruption event, which occurred from the 13th to the 15th of January 2022. Various datasets, including Sentinel-5 Precursor (TROPOMI), the Ozone Monitoring Instrument (OMI), and the Ozone Mapping and Profiler Suite (OMPS), were utilized to observe the transport of these constituents. The TROPOMI data revealed westward-traveling SO2 plumes over Australia and the Indian Ocean towards Africa, eventually reaching the Republic of South Africa (RSA), as confirmed by ground-based monitoring stations of the South African Air Quality Information System (SAAQIS). Moreover, the Cloud-Aerosol Lidar and Infrared Pathfinder Satellite Observations (CALIPSO) demonstrated sulphate aerosols at heights ranging from 18 to 28 km with a plume thickness of 1 to 4 km. The results of this study demonstrate that multiple remote sensing datasets can effectively investigate the dispersion and long-range transport of volcanic constituents.

关键词： volcanic emission Sentinel-5P aerosols SO2 transport

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Enhanced removal of viral aerosols using nanosilver/TiO2-chitosan filters combined with a negative air ionizer

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Journal of Environmental Chemical Engineering 2024年第3期12卷

作者： Dlamini, Wonder Nathi Yao, Ting-Ching Lee, Hsin-Jui Berekute, Abiyu Kerebo Sallah-Ud-Din, Rasham Siregar, Sepridawati Yu, Kuo-Pin Institute of Environmental and Occupational Health Sciences National Yang-Ming Chiao-Tung University Taipei Taiwan Department of International Ph.D. Program in Environmental Sciences and Technology University System of Taiwan Taipei Taiwan Department of Chemistry College of Natural and Computational Sciences Arba Minch University Arbaminch Ethiopia Faculty of Mineral Technology AKPRIND Institute of Science & Technology Yogyakarta Indonesia

The presence of airborne viruses in bioaerosols is a significant and ongoing public health concern. In this context, this study aimed to develop a new filter that integrates nanosilver into a TiO2-chitosan matrix (nano-Ag/TiO2-CS) to inactivate the non-enveloped bacteriophage MS2 as a viral aerosol surrogate. The materials were characterized using various techniques, such as X-ray diffraction (XRD), scanning electron microscopy (SEM), high-resolution transmission electron microscopy (HR-TEM), and X-ray photoelectron spectroscopy (XPS). The SEM images showed that the nano-Ag particles were spheres with a high surface area for virus interactions and that the fiber surfaces were covered by nano-Ag, which enhanced contact with viruses. The optimal 5 wt% nano-Ag/TiO2-CS filter combined with a negative air ionizer (NAI) showed the highest viral aerosol removal efficiency, which reached 97 %. The use of an NAI during filtration enhanced the inactivation of the viral aerosols. A long-term antiviral efficacy assessment showed that the nano-Ag/TiO2-CS filter demonstrated robust durability, which is vital for real-world applications. The nanofilter proposed in this work is simple, safe, and cost-effective for inactivating viral aerosols to improve indoor air quality. © 2024 Elsevier Ltd

关键词： aerosols

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Sub-weekly signatures relate ultrafine aerosols enriched in metals from intensive farming and urban pollution to Kawasaki disease

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ENVIRONMENTAL RESEARCH LETTERS 2023年第7期18卷 074011-074011页

作者： Rodo, Xavier Navarro-Gallinad, Albert Kojima, Tomoko Morgui, Josep-Anton Borras, Silvia Fontal, Alejandro ICREA Barcelona Catalonia Spain IS Global Climate & Hlth CLIMA Program Barcelona Catalonia Spain Osaka Univ Grad Sch Human Sci Osaka Japan Trinity Coll Dublin ADAPT Ctr Digital Content Dublin Ireland Kumamoto Univ Fac Adv Sci & Technol Kumamoto Japan

Air pollution (urban, industrial or rural) has been linked to a myriad of human ailments despite clear mechanistic associations that are often not thoroughly established. Daily variability of fine aerosols in a surveillance campaign in south Japan shows a striking coevolution between their trace elements (metal and metalloid, MM) content and Kawasaki disease (KD) admissions, suggesting a strong dynamical link. These aerosol MM could instigate an immune response that, along with genetic susceptibility, would lead to KD development. This association may account for over 40% of the total variability in the disease, being dominated by a clear sub-weekly cycle (SWC1). Thanks to both an unprecedented daily KD epidemiological record going back to 1970, light detection and ranging (LIDAR) atmospheric backscattering profiles for the interval 2010-2016 and HYSPLIT simulations with numerous sensitivity analyses, we can trace this SWC1 variability to occur concomitantly from sub-seasonal to interannual timescales in both KD and aerosols. This SWC1 appears to connect or disconnect Japan to air intrusions from above the planetary boundary layer (PBL), having their source in industrial and agricultural areas in NE Asia and points to a stronger case for an agricultural source for the exposure as opposed to urban pollution. The KD maxima always occur in full synchrony with the arrival of very small (mu m;PM1) particles showing that ultrafine aerosols appear as a necessary cofactor in the occurrence of KD and sets the field to associate other similar human diseases. Our study shows how signal-detection approaches can be useful to uncover hidden associations between the environment and human health, otherwise unnoticed and help set new early-warning systems for disease prevention.

关键词： aerosols human health Kawasaki disease ultrafine particles agricultural by products wind intrusions transient signatures

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Efficacy of Do-It-Yourself air filtration units in reducing exposure to simulated respiratory aerosols

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BUILDING AND ENVIRONMENT 2023年 229卷 109920页

作者： Derk, Raymond C. Coyle, Jayme P. Lindsley, William G. Blachere, Francoise M. Lemons, Angela R. Service, Samantha K. Martin Jr, Stephen B. Mead, Kenneth R. Fotta, Steven A. Reynolds, Jeffrey S. McKinney, Walter G. Sinsel, Erik W. Beezhold, Donald H. Noti, John D. CDCP Hlth Effects Lab Div Natl Inst Occupat Safety & Hlth 1000 Fredrick Lane Morgantown WV 26508 USA CDCP Resp Hlth Div Natl Inst Occupat Safety & Hlth 1000 Fredrick Lane Morgantown WV 26505 USA CDCP Div Field Studies & Engn Natl Inst Occupat Safety & Hlth Cincinnati OH 45226 USA CDC NIOSH HELD 1000 Fredrick Lane Morgantown WV 26508 USA

Many respiratory diseases, including COVID-19, can be spread by aerosols expelled by infected people when they cough, talk, sing, or exhale. Exposure to these aerosols indoors can be reduced by portable air filtration units (air cleaners). Homemade or Do-It-Yourself (DIY) air filtration units are a popular alternative to commercially produced devices, but performance data is limited. Our study used a speaker-audience model to examine the efficacy of two popular types of DIY air filtration units, the Corsi-Rosenthal cube and a modified Ford air filtration unit, in reducing exposure to simulated respiratory aerosols within a mock classroom. Experiments were conducted using four breathing simulators at different locations in the room, one acting as the respiratory aerosol source and three as recipients. Optical particle spectrometers monitored simulated respiratory aerosol particles (0.3-3 mu m) as they dispersed throughout the room. Using two DIY cubes (in the front and back of the room) increased the air change rate as much as 12.4 over room ventilation, depending on filter thickness and fan airflow. Using multiple linear regression, each unit increase of air change reduced exposure by 10%. Increasing the number of filters, filter thickness, and fan airflow significantly enhanced the air change rate, which resulted in exposure reductions of up to 73%. Our results show DIY air filtration units can be an effective means of reducing aerosol exposure. However, they also show performance of DIY units can vary considerably depending upon their design, construction, and positioning, and users should be mindful of these limitations.

关键词： Do-it-yourself air cleaner Indoor air quality Inhalation exposure Ventilation Air filters aerosols

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