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aerosols consistently suppress the convective boundary layer development

ATMOSPHERIC RESEARCH 2022年 269卷

作者： Zhang, Xiaoyan Cai, Changjie Hu, Xiao-Ming Gao, Lan Xu, Xiyan Hu, Jun Chen, Haishan Nanjing Univ Informat Sci & Technol Joint Int Res Lab Climate & Environm Change ILCEC Key Lab Meteorol Disaster Minist Educ KLMECIC FEMD Nanjing 210044 Peoples R China Nanjing Univ Informat Sci & Technol Sch Atmospher Sci Nanjing 210044 Peoples R China Univ Oklahoma Hlth Sci Ctr Dept Occupat & Environm Hlth Oklahoma City OK USA Univ Oklahoma Ctr Anal & Predict Storms Norman OK 73019 USA Univ Oklahoma Sch Meteorol Norman OK 73019 USA Chinese Acad Sci Inst Atmospher Phys Key Lab Reg Climate Environm Temperate East Asia Beijing Peoples R China Fujian Acad Environm Sci Fuzhou Peoples R China Nanjing Univ Informat Sci & Technol Sch Atmospher Phys Nanjing Peoples R China

aerosols with different vertical distribution and various optical properties induce diverse heating rates and thereby affecting convective boundary layer (CBL) development. Our results showed consistent CBL-suppression of aerosols during daytime with numerical experiments, in which aerosols were specified at different heights with synthesized single scattering albedo from 64 studies and asymmetry factor from 20 studies globally. Absorbing aerosols concentrated below but close to the CBL top had the strongest suppression effect on CBL development relative to that concentrated near surface or above CBL. Aerosol cooling effect by attenuating incident solar radiation and surface heat flux exceeded its warming effect by reheating the atmosphere layer with absorbed shortwave radiation, and eventually declined net heating rate, which inhibited CBL development, lowered mixed-layer potential temperature and stabilized atmospheric stratification. Stove effect of absorbing aerosols (CBL enhancement) under a zero background aerosol extinction coefficient is negligible for dominant dome effect (CBL suppression) which consistently suppresses CBL development regardless of aerosol vertical height and background aerosol extinction coefficient. Our study also highlighted the importance of specifying background aerosol extinction coefficient in numerical experiments for accurate assessment of aerosol radiative forcing and CBL-aerosol interactions.

关键词： aerosols Convective boundary layer Dome effect Optical property Background aerosol extinction coefficient

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Dose- and Time-Dependent Effects of Different Nickel-Based Thermal Spray Coating aerosols on Lung Toxicity and Histopathology Using an Animal Inhalation Model

SSRN

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SSRN 2025年

作者： Antonini, James M. Afshari, Aliakbar A. Meighan, Terence G. McKinney, Walter G. Zeidler-Erdely, Patti C. Erdely, Aaron Friend, Sherri Lee, Eun Gyung Moore, Rebecca Kodali, Vamsi Health Effects Laboratory Division National Institute for Occupational Safety and Health MorgantownWV26508 United States Respiratory Health Division National Institute for Occupational Safety and Health MorgantownWV26508 United States Inotiv-RTP MorrisvilleNC27560 United States Centers for Disease Control and Prevention United States

Thermal spray coating is an emerging occupational process. Information about the health effects of the aerosols generated is limited. A thermal spray coating exposure system has been developed to perform inhalation studies that simulate workplace exposures. Sprague-Dawley rats were exposed to aerosols generated during thermal spray coating using two nickel (Ni)-based consumables - PMET885 and PMET876. Cumulative target concentrations [exposure concentration (C;mg/m3) x exposure time (T;hr)] were: (1) HIGH – 400 mg/m3 (25 mg/m3 x 4 hr/d x 4 d);(2) MIDDLE – 80 mg/m3 (5 mg/m3 x 4 hr/d x 4 d);(3) LOW – 16 mg/m3 (4 mg/m3 x 4 hr/d x1 d). At 4 and 30 d post-exposure, lung toxicity was assessed by bronchoalveolar lavage and histopathology. Metal composition was: PMET885 (97% Ni, 2% Al) and PMET876 (56% Ni, 17% Cr, 17% Mo, 5% Fe, 3% Mn). Inhalation exposure to the Ni-based thermal spray coating aerosols caused significant lung toxicity in a dose- and time-dependent manner. The PMET885 aerosol was the more pneumotoxic. Lung fibrosis was observed after exposure to the PMET885 aerosol but not PMET876. The varied lung responses observed were dependent on the metal composition and solubility properties of the generated particles. © 2025, The Authors. All rights reserved.

关键词： aerosols

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aerosols are not Spherical Cows: Using Discrete Dipole Approximation to Model the Properties of Fractal Particles

arXiv

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arXiv 2023年

作者： Lodge, Matt G. Wakeford, Hannah R. Leinhardt, Zoe M. School of Physics HH Wills Physics Laboratory Tyndall Avenue BristolBS8 1TL United Kingdom

The optical properties of particulate-matter aerosols, within the context of exoplanet and brown dwarf atmospheres, are compared using three different models: Mie theory, Modified Mean Field (MMF) Theory, and Discrete Dipole Approximation (DDA). Previous results have demonstrated that fractal haze particles (MMF and DDA) absorb much less long-wavelength radiation than their spherical counterparts (Mie), however it is shown here that the opposite can also be true if a more varying refractive index profile is used. Additionally, it is demonstrated that absorption/scattering cross-sections, and the asymmetry parameter, are underestimated if Mie theory is used. Although DDA can be used to obtain more accurate results, it is known to be much more computationally intensive;to avoid this, the use of low-resolution aerosol models is explored, which could dramatically speed up the process of obtaining accurate computations of optical cross-sections within a certain parameter space. The validity of DDA is probed for wavelengths of interest for observations of aerosols within exoplanet and brown dwarf atmospheres (0.2 − 15 µm). Finally, novel code is presented to compare the results of Mie, MMF and DDA theories (CORAL: Comparison Of Radiative AnaLyses), as well as to increase and decrease the resolution of DDA shape files accordingly (SPHERIFY). Both codes can be applied to a range of other interesting astrophysical environments in addition to exoplanet atmospheres, for example dust grains within protoplanetary disks. © 2023, CC BY.

关键词： aerosols

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A Numerical Simulation Model for Realistic Representation of the Evolution, Transport, and Deposition of Hygroscopic aerosols in the Respiratory Tract

SSRN

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SSRN 2024年

作者： Liu, Yu Chen, Xiaole Xie, Jun Xie, Xiaojian Zhang, Yi School of Energy and Mechanical Engineering Nanjing Normal University Jiangsu Nanjing210042 China

Achieving accurate simulation of respiratory drug delivery is essential for understanding nebulized droplet behaviour and assessing aerosol exposure risk. Previous studies have shown that the dynamic evolution of droplets can be analyzed more accurately using a two-way coupling method between the continuous phase (i.e., airflow) and the discrete phase (droplets), as the highly concentrated aerosol exchanges water vapor mass with the environment during the nebulization process. In order to verify the rationality and scientific validity of the two-way coupling method and to provide a more comprehensive quantitative analysis, we simulated the nebulized inhalation process of droplets under different environmental temperature and humidity conditions in an idealized mouth-throat (MT) airway model, and also recorded the droplet/particle deposition fractions ( ) and deposition patterns, and analyzed them in comparison with the experimental data. The interactions between the continuous and discrete phases are modeled by an innovative two-way coupling method of aerosol-water vapor interactions in highly concentrated droplets by the particle parcel method. The simulation results illustrate that the predictions of the droplets by the two-way coupling method used are in good agreement with the experimental data and the overall trend can be reasonably explained. This may have significance for the study of drug aerosol delivery efficiency in the human respiratory tract. In addition, as evaporation of nebulized droplets is slowed down in warm and wet condition, which may further affect the deposition of nebulized droplets in the lower respiratory tract. © 2024, The Authors. All rights reserved.

关键词： aerosols

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Impacts of Meteorology and Mixing Height on Radioactive and Stable aerosols in Bratislava, Slovakia

SSRN

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SSRN 2024年

作者： Sultani, Mohammad Alem Bulko, Martin Sýkora, Ivan Müllerová, Monika Masarik, Jozef Tonhauzer, Peter Department of Nuclear Physics and Biophysics Faculty of Mathematics Physics and Informatics Comenius University in Bratislava Mlynská Dolina Bratislava842 48 Slovakia Slovak Hydrometeorological Institute Jeséniova 17 Bratislava833 15 Slovakia

This study investigated the variability of radioactive and stable aerosols (7Be, 210Pb, 137Cs, 40K, PM10, and PM2.5) in relation to mixing layer height (MLH) based on outdoor radon and meteorological factors in Bratislava, Slovakia from 2017 to 2021. Aerosol concentrations exhibit distinct seasonal patterns, with higher 7Be concentrations in summer and lower in winter, while 137Cs, 40K, 210Pb, PM10 and PM2.5 showed almost the opposite trends. Different statistical techniques, including Pearson's correlation analysis, multiple regression analysis (MRA), and canonical correlation analysis (CCA), were employed to elucidate the intricate relationships between aerosol concentrations, MLH, and meteorological parameters. The MRA identified a significant correlation between aerosol variability and specific predictors, while the CCA highlighted the differential influence of MLH and meteorological parameters on aerosol concentrations. The analysis revealed that temperature, MLH, and relative humidity are the primary factors influencing aerosol concentrations, underscoring their pivotal role in environmental dynamics. © 2024, The Authors. All rights reserved.

关键词： aerosols

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Vertically Resolved Meteorological Adjustments of aerosols and Trace Gases in Beijing, Taiyuan, and Hefei by Using Rf Model

SSRN

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SSRN 2024年

作者： Khayyam, Junaid Xie, Pinhua Xu, Jin Tian, Xin Feng, Hu Qinjin, Wei Hefei Institutes of Physical Science Chinese Academy of Sciences Hefei230031 China University of Science and Technology of China Hefei230026 China Key laboratory of Environmental Optical and Technology Anhui Institute of Optics and Fine Mechanics Hefei Institutes of Physical Science Chinese Academy of Sciences Hefei230031 China Institutes of Physical Science and Information Technology Anhui University Hefei230601 China

Air pollution represents a complex phenomenon defined by the presence of various gases and particulate matter, leading to intricate spatio-temporal fluctuations. This study aims to enhance our understanding of how meteorological factors influence trace gases and aerosols, exacerbating air pollution in various geographical locations, specifically in Beijing's Fengtai (BJFT), Taiyuan City (SXTY), and Hefei's Science Island (HFDP). The study employs 2D-MAX-DOAS observations and utilizes the Random Forest (RF) model to decouple the influence of meteorological conditions from pollutant data. The vertical profile of nitrogen dioxide (NO2), sulfur dioxide (SO2), formaldehyde (HCHO), and aerosols at each study site was classified into four distinct layers, followed by conducting a meteorological decoupling analysis on each layer. This decoupling analysis demonstrates that meteorology significantly influences aerosols across all sites, with reductions ranging from 75% to 95% after de-weathering. SO2 shows minimal susceptibility, with the changes ranging from ±20% to ±60% after de-weathering. Among all sites, BJFT's pollutants exhibit less susceptibility overall, while pollutants at HFDP are more susceptible. The findings further reveal significant meteorological interventions in pollutants in surface layers (0.05 km and 0.2 – 0.4 km) at BJFT, with some exceptions at SXTY. However, pollutants, particularly NO2 and aerosols in higher layers (0.6 – 0.8 km and 1.0 – 1.2 km) at HFDP, also experience significant meteorological interferences. The findings at HFDP and SXTY reveal that removing meteorological influence also adjusts the profile shape of pollutants. For instance, the NO2 profile at HFDP during the winter season shifted from a bimodal to an exponential shape after de-weathering. Overall, this study sheds light on the complex interplay between meteorological factors and trace gases at various altitudes across different geographic locations, offering insights crucial for

关键词： aerosols

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Effects of Clouds, aerosols and Shadows on Solar Energy Potential on Urban Rooftops Using Earth Observation Data and Digital Surface Models

SSRN

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SSRN 2024年

作者： Hou, Xinyuan Papachristopoulou, Kyriakoula Saint-Drenan, Yves-Marie Kosmopoulos, Panagiotis Psiloglou, Basil Kazadzis, Stelios National Observatory of Athens Greece

This study combines high-frequency Earth observation data (Copernicus Atmosphere Monitoring Service) and very-high-resolution digital surface models, to explore the effects of clouds and aerosols in conjunction with shadows on solar energy potential on urban rooftops. We focus on the assessment of two municipalities in the city of Athens (Greece). Besides quantifying the shadowing effect from the adjacent buildings and constructions, the previously scarcely considered effects of clouds and aerosols on the solar radiation availability on the rooftops and their inter-annual variability are investigated. The results of this investigation show that the atmosphere and building shadows cause monthly 30–60 kWh m-2 of solar radiation loss on urban rooftops in Athens. The mean monthly cloud effect ranges from 5% in summer to >30% in winter;the mean aerosol effect has its peak of 8% in August and © 2024, The Authors. All rights reserved.

关键词： aerosols

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The Impact of aerosols as Ice Nuclei On Microphysics and Electrification In the Cumulus Model

SSRN

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SSRN 2024年

作者： Yang, Yi Deng, W. Li, F. Zhang, Tianyu School of Geographical Sciences Hebei Normal University Shijiazhuang050024 China Hebei Key Laboratory of Environmental Change and Ecological Construction Shijiazhuang050024 China Hebei Technology Innovation Center for Remote Sensing Identification of Environmental Change Shijiazhuang050024 China Institute of Atmospheric Physics Chinese Academy of Sciences Beijing100029 China University of Chinese Academy of Sciences Beijing100049 China Aerospace Information Research Institute the Chinese Academy of Sciences Beijing100094 China

Here, an ice-nucleation parameterization associated with aerosol acting as ice nuclei was implanted into a two-dimensional numerical cumulus model. To explore the impact of ice nuclei on microphysical and electrical processes, a comparison was conducted with the original approach, which employs an empirical formula. Simulation results indicate that ice nuclei greatly impacted microphysical evolution in the ice-nucleation process, reducing total liquid precipitation amounts and causing a slight precipitation delay, as well as increasing the diameter and mixing ratio of ice crystals and the expansion of the vertical distribution of ice crystals. This led to a notable change in electrification in thunderstorms. The increase of ice crystal diameter was the dominant contributor to the enhancement of electrification using the new parameterization. Additionally, unlike the structure of thunderclouds in a mature stage, which always retain a normal dipole structure adopting the empirical formula, a tripole structure developed a lower positive charge and the polarity inversion with upper negative and lower positive charges occurred when the new parameterization was adopted. This predominately was the result of abundant ice-crystals present below the reversal temperature. The electrification characteristics of thunderstorms may have a close connection with lightning activity. It has been found that charge structure changed significantly in the two cases, with the tripolar charge structure facilitating the production of inverted intra-cloud (IC) flashes and negative Cloud-to-ground (CG) flashes in the LP case;additionally, the YS case may be able to develop normal IC lightning and positive CG flashes. Therefore, it is important it will be very meaningful to obtain greater insight into the characteristics of thunderstorms electrification with cumulus model added aerosols. © 2024, The Authors. All rights reserved.

关键词： aerosols

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Modelling the Ejection of Primary aerosols During the Fast Pyrolysis of Biomass Anisotropic Particles

SSRN

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SSRN 2024年

作者： Sánchez, Mario A. Maya, Juan C. Chejne, Farid Pecha, M. Brennan Quinchía, Adriana M. Ruiz, Nevis A. Ciesielski, Peter N. Universidad EIA Colombia Universidad Nacional de Colombia Medellín Colombia Renewable Resources and Enabling Sciences Center United States

A model for the fast pyrolysis of anisotropic biomass particles is presented which considers bubbling dynamics within the liquid intermediate phase (metaplast) and aerosol ejection from this phase. The model employs the population balance equation and the method of moments to estimate the production rate and resultant size distribution of aerosol ejections, incorporating a detailed CRECK reaction mechanism, and considers the effect of anisotropic biomass microstructure on the intraparticle transport of mass and energy. This study investigates the impact of particle size, heating rate (heat transfer coefficient), and lignocellulosic composition on aerosol ejection. The model predicts that, at high heating rates (convective heat transfer coefficient of 359 W/m2°C), aerosols can contribute over 20% to the heavy fraction yield in bio-oil for small particles (1 mm diameter, 4 mm length). The model can predict aerosol size distribution and surface area, indicating an average size of 20 µm for bubbles and 5 µm for aerosols during increased bubble production and aerosol ejection rates. These findings are consistent with prior experimental results and provide essential information for future modeling of extra-particle reactions of the aerosols as they progress through the reactor. © 2024, The Authors. All rights reserved.

关键词： aerosols

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A Long-Term Study on Sources, Enrichments, and Inhalation Risk Assessments of aerosols (Pm10) at Urban/Industrial City of Hyderabad in Southern India

SSRN

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SSRN 2024年

作者： Attri, Pradeep Tiwari, Devleena Mani Satyanarayanan, M. Reddy, Dontireddy Venkat Kumar, Devender Centre for Earth Ocean and Atmospheric Sciences University of Hyderabad Telangana 500046 India CSIR-National Geophysical Research Institute Telangana Hyderabad500007 India

The present study investigates the sources and enrichment of major ions, trace, and heavy metals, along with their inhalation risk assessment in PM10 from 2019-21 at an urban/industrial location in Hyderabad, India. Several chemical ratios were explored to understand the mass closure of these aerosols. High K+nss was observed during post-monsoon and winter, which is attributed to the emissions from the crop residue burning. Metals like Cr, Mo, Cs, Ce and Pb were observed to be 22 %, 88 %, 92 %, 20 % and 18 % higher than WHO’s daily and annual limit. Transition metals like Fe and Mn showed dominance of H2O regime in the atmosphere by catalysing HO2 to form H2O. A strong positive correlation of Cs and Mo with Rb was observed throughout the sampling period, suggesting crustal sources of Mo and Cs. Cu/Pb, Cu/Zn, V/Pb, and As/Se ratios suggested dominance of vehicular emission with no significant contribution of coal combustion sources. Positive associations between K+nss, Sn and Cd suggested burning sources. No significant association was observed between Cr(VI) and Sn, therefore, incineration processes did not contribute to the emissions at studied site. In the present study, Cr(VI)/Sn was used for the first time to identify the industrial and electronic-plastic waste burning (EPWB) sources. High Cr(VI)/Sn suggested contribution of industrial emissions throughout the sampling period, except post-monsoon. Using Fe and Ti as reference, enrichment of Ba and Se during post-monsoon, Sb and Cr during post-monsoon 2019 and winter 2020 and Co during summer were observed. Carcinogenic Cr(VI) was observed only during post-monsoon 2019, whereas non-carcinogenic risk for all considered metals was observed throughout the sampling duration. © 2024, The Authors. All rights reserved.

关键词： aerosols

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