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Mathematical modeling of monodisperse nanoparticle production in aerosols using separation in an electric field

SOFT COMPUTING 2021年第16期25卷 11347-11362页

作者： Gomes, Thais L. C. Lobato, Fran S. Borges, Lucas C. Arouca, Fabio O. Damasceno, Joao J. R. Univ Fed Uberlandia Sch Chem Engn Av Joao Naves de Avila 2121 BR-38400900 Uberlandia MG Brazil

The wide range of applications of particulate materials in the modern industry, as well as growing concerns about their potential risks to human health and the environment, has boosted studies related to the production, control, and classification of nanoparticles. Differential mobility analyzers (DMAs) are one of the main technologies used to characterize the size distribution of nanoparticles in aerosols. However, the high price and complexity of this equipment have been limiting factors for its use. Thus, the purpose of this study was to evaluate the performance of a Long-DMA, designed and built with its own technology and to propose and solve an inverse problem to determine the monodisperse aerosol concentration distribution. The polydisperse aerosols were generated by atomization of NaCl solutions with 0.1, 0.5, and 1.0 g L-1 concentrations. In order to estimate the theoretical nanoparticle size distributions of monodisperse aerosols, a new mobility balance was proposed. This was based on the Wiedensohler charge distribution associated with a loss parameter, obtained considering a formulation and solution of an optimization problem by using the differential evolution algorithm. The Long-DMA was able to produce monodisperse aerosols for all the saline concentrations evaluated, showing evidence of its potential for classifying nanoparticles. Comparisons between the experimental and theoretical results showed that the proposed mobility balance was able to satisfactorily describe the distributions related to monodisperse aerosols. The proposed methodology was able to estimate the monodisperse aerosol distribution in intermediate solution concentration using only the data about the highest and lowest concentrations. It is worth mentioning that the cost of the designed equipment was approximately 10% of the commercial equipment value.

关键词： Monodisperse nanoparticles aerosols Electric field Modeling Optimization

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Climate models generally underrepresent the warming by Central Africa biomass-burning aerosols over the Southeast Atlantic

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SCIENCE ADVANCES 2021年第41期7卷 000-000页

作者： Mallet, Marc Nabat, Pierre Johnson, Ben Michou, Martine Haywood, Jim M. Chen, Cheng Dubovik, Oleg Univ Toulouse CNRS Meteo France CNRM Toulouse France Met Off Exeter EX1 3PB Devon England Univ Exeter Coll Engn Math & Phys Sci Exeter EX4 4QE Devon England GRASP SAS F-59000 Lille France Univ Lille LOA Lab Opt Atmospher CNRS UMR 8518 F-59000 Lille France

The radiative budget, cloud properties, and precipitation over tropical Africa are influenced by solar absorption by biomass-burning aerosols (BBA) from Central Africa. Recent field campaigns, reinforced by new remote-sensing and aerosol climatology datasets, have highlighted the absorbing nature of the elevated BBA layers over the South-East Atlantic (SEA), indicating that the absorption could be stronger than previously thought. We show that most of the latest generation of general circulation models (GCMs) from the sixth phase of the Coupled Model Intercomparison Project 6 (CMIP6) underestimates the absorption of BBA over the SEA. This underlines why many (similar to 75%) CMIP6 models do not fully capture the intense positive (warming) direct radiative forcing at the top of the atmosphere observed over this region. In addition, underestimating the magnitude of the BBA-induced solar heating could lead to misrepresentations of the low-level cloud responses and fast precipitation feedbacks that are induced by BBA in tropical regions.

关键词： aerosols

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Hygroscopicity of Hofmeister Salts and Glycine aerosols-Salt Specific Interactions

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JOURNAL OF PHYSICAL CHEMISTRY A 2021年第7期125卷 1589-1597页

作者： Ashraf, Hamad Guo, Yaxin Wang, Na Pang, Shufeng Zhang, Yun-Hong Beijing Inst Technol Inst Chem Phys Sch Chem & Chem Engn Beijing 100081 Peoples R China

The Hofmeister effect of inorganic ions to precipitate proteins has been used to understand the coagulation phenomenon in colloid and protein science. Herein, for the first time, this effect is studied on the hygroscopicity of aerosols using ATR-FTIR spectroscopy. The representative Hofmeister salts (MgSO4, KCl, NH4NO3) and amino acid (glycine) with different amino acid/salt molar ratios (ASRs) are mixed and atomized into micrometer-sized particles. For mixed kosmotrope (MgSO4)/glycine and chaotrope (NH4NO3)/glycine with an ASR of 1:1, both ERHs (efflorescence relative humidities) and DRHs (deliquescence relative humidities) are absent. However, for the mixtures of glycine and neutral salt (KCl), no DRH is observed while 66.2 and 61.4% ERH of glycine is detected for mixtures with ASRs of 1:1 and 1:3, respectively, which is similar to pure glycine. For the mixture of NH4NO3/glycine with an ASR of 1:3, ERH and DRH are found to be 15.4 and 32.2% RH, less than that of pure NH4NO3. Further, interactions between glycine-salt and/or water is also studied in the mixtures during hydration and dehydration. Water-mediated ion-glycine interaction is detected based on the two glycine bands merging into one band. Glycine-SO(4)(2- )interaction is present for glycine/sulfate in all ASRs, while glycine-NO3- interaction is only seen for 1:3 glycine/NH4NO3 mixtures during hydration. This work opens a window to understand the Hofmeister effect on the hygroscopicity of atmospheric aerosols.

关键词： Salts Dehydration Mixtures aerosols Hydration

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Integrated Remote Sensing and Crop Model Approach for Impact Assessment of aerosols on Biomass Accumulation of Maize

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IEEE JOURNAL OF SELECTED TOPICS IN APPLIED EARTH OBSERVATIONS AND REMOTE SENSING 2021年 14卷 7237-7245页

作者： Xie, Hongfei Zhao, Junfang Yan, Weixiong Kong, Xiangna Peng, Huiwen Chinese Acad Meteorol Sci State Key Lab Severe Weather Beijing 100081 Peoples R China Ningxia Inst Meteorol Sci Key Lab Meteorol Disaster Monitoring & Early Warn Yinchuan 750002 Ningxia Peoples R China Sichuan Agr Univ Resources Coll Chengdu 611130 Peoples R China

The remote sensing data and crop model were used to explore the dynamic changes and accumulation of maize biomass in China caused by aerosols in this study. Maize varieties were divided into spring maize and summer maize. Two spring maize and three summer maize stations were selected. The results indicated that the solar radiation through all stages of maize development was reduced by aerosols, with daily average reductions of 3.23 MJ center dot m(-2)center dot d(-1) for spring maize and 8.96 MJ center dot m(-2)center dot d(-1) for summer maize from 2001 to 2014. aerosols reduced the daily actual maize biomass in the study area, with an average daily decrease of 3.78 g center dot m(-2)center dot d(-1) from 2001 to 2014. Moreover, the changes in daily actual biomass caused by aerosols varied in different growth stages. The reduction in daily actual biomass caused by aerosols in the stage of emergence-flowering was larger than that in the stage of flowering-maturity. For spring maize, the changes in daily actual biomass caused by aerosols were -2.12 to -2.29 g center dot m(-2)center dot d(-1) from emergence to flowering and -0.72 to 0.08 g center dot m(-2)center dot d(-1) from flowering to maturity. For summer maize, the changes in daily actual biomass caused by aerosols were -8.94 to -3.45 g center dot m(-2)center dot d(-1) from emergence to flowering and -6.50 to -2.24 g center dot m(-2)center dot d(-1) from flowering to maturity. In addition, the annual maize biomass from 2001 to 2014 at five stations clearly decreased owing to aerosols. Moreover, the decrease in the annual biomass of summer maize was greater than that of spring maize, with an average decrease of 27.77% in summer maize biomass and 10.94% in spring maize biomass.

关键词： aerosols Biomass Agriculture Springs Atmospheric modeling Biological system modeling Licenses 6S model aerosol Agricultural Production Systems sIMulator (APSIM) model maize biomass remote sensing

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Distributions of water-soluble ions in size-aggregated aerosols over the Southern Ocean and coastal Antarctica

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ENVIRONMENTAL SCIENCE-PROCESSES & IMPACTS 2021年第9期23卷 1316-1327页

作者： Xu, Guojie Chen, Liqi Xu, Tianyi He, Shichang Gao, Yuan Nanjing Univ Informat Sci & Technol China Meteorol Adm Key Lab Aerosol Cloud Precipitat 219 Ningliu Rd Nanjing 210044 Jiangsu Peoples R China Rutgers State Univ Dept Earth & Environm Sci Newark NJ 07102 USA Minist Nat Resources MNR Inst Oceanog TIO 3 Key Lab Global Change & Marine Atmospher Chem GCM Xiamen 361005 Peoples R China State Ocean Adm Sansha Marine Envimnmental Monitoring Ctr Haikou 570311 Hainan Peoples R China

To investigate mass size distributions of water-soluble ions in aerosols in the marine boundary layer (MBL) over the Southern Ocean, size-segregated (0.056-18 mu m in aerodynamic diameter) aerosols were collected on the 28(th) Chinese National Antarctic Research Expedition (CHINARE) cruise from November 2011 to March 2012. Major water-soluble inorganic and organic species in aerosols were analyzed by ion chromatography (IC). Results showed that high loadings of aerosol mass were observed over the western sector of the Southern Ocean, attributed to the high mass loadings of Na+ and Cl- in the particles >1.0 mu m in diameter and high mass loadings of non-sea-salt (nss) SO42- and methanesulfonate (MSA) in the particles <1.0 mu m in diameter. Nss-SO42- and MSA accounted for similar to 40% of the total mass in aerosols with particle size <0.56 mu m over the eastern sector of the Southern Ocean, while it was elevated to more than 60% over the western sector of the Southern Ocean that could be linked with high marine productivity reflected by high chlorophyll-a occurrence in surface waters in that region. MSA/nss-SO42- ratios showed an increasing trend as latitude increased in the southern hemisphere with a dramatic increase south of 60 degrees S and the variation of MSA may shape the spatial distribution of the ratios. High MSA concentration and MSA/nss-SO42- ratios were observed in west Antarctica, especially in the supermicron particles. A bimodal mass size distribution of total Ca2+ with a small peak in the 0.18-0.32 mu m size range was observed, suggesting different sea spray aerosol (SSA) production mechanisms. Nss-SO42-, MSA was mainly enriched in the particle size range of 0.18 mu m to 0.56 mu m. The concentrations of formate and oxalate were low and detected only in certain size particles, mainly in the range <0.56-1.8 mu m. Further studies should be conducted over the remote Southern Ocean to reveal marine ecosystem-aerosol-climate interactions.

关键词： aerosols

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Are aerosols on the leaves of apricot trees (Prunus armeniaca) signalizing the activity of a hidden paleo-supervolcano in a steppe?

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ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH 2021年第40期28卷 57424-57439页

作者： Glinyanova, Irina Fomichev, Valery Asanova, Natali Volgograd State Tech Univ Inst Architecture & Construct Fac Engn Syst & Technosphere Safety 1 Akad Skaya St Volgograd 400074 Russia Volgograd State Tech Univ Dept Gen & Inorgan Chem 28 Lenin Av Volgograd 400005 Russia Volgograd State Tech Univ Dept Appl Math 28 Lenin Av Volgograd 400005 Russia

aerosols on plant leaves make it possible to assess the quality of air in settlements. The purpose of this work was to assess the acidity and specific electrical conductivity of aerosol suspensions (by washing off aerosol particles from the leaves of apricot trees (Prunus armeniaca)), which characterize the air pollution in the residential area of the Svetly Yar settlement (Volgograd region, Russia) during the spring-summer of 2019. The research hypothesis was as follows: Acidic mineralized aerosols with a mixed source are present in Svetly Yar. The differences were checked by the Student's t-test and evaluated at the level of significance of p = 0.05. The results indicated the presence of acidic (pH = 4.56 + 0.02) and highly mineralized aerosols (EC = 130.41 + 0.17 mu S/cm) in the ambient air of the Svetly Yar residential area during the spring-summer of 2019 and revealed environmental risks for the population in comparison with aerosol suspensions from a (relatively) clean location (pH = 6.46 + 0.02;EC = 37.61 + 0.19 mu S/cm). The authors confirmed their hypothesis in favor of mixed source acidic mineralized aerosols in the residential area of the Svetly Yar village. The anthropogenic sources were the industrial zones of Svetly Yar, the southern part of the city of Volgograd and artificial sedimentation tanks in the southwestern part of Svetly Yar. A natural source of pollution in the vicinity of Svetly Yar may be hidden geologically active structures: faults in the Earth's crust, a salt diapir, an underground ancient semiactive volcanic zone on a steppe, etc.

关键词： aerosols Aerosol pollution Natural aerosol particles Anthropogenic pollution Acidity Electrical conductivity Geologically active structures of the Earth Geodynamic zones Underground ancient volcanic areas Active faults

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Humidity-Dependent Phase State of Gasoline Vehicle Emission-Related aerosols

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ENVIRONMENTAL SCIENCE & TECHNOLOGY 2021年第2期55卷 832-841页

作者： Meng, Xiangxinyue Wu, Zhijun Guo, Song Wang, Hui Liu, Kefan Zong, Taomou Liu, Yuechen Zhang, Wenbin Zhang, Zhou Chen, Shiyi Zeng, Limin Hallquist, Mattias Shuai, Shijin Hu, Min Peking Univ Coll Environm Sci & Engn State Key Joint Lab Environm Simulat & Pollut Con Int Joint Lab Reg Pollut Control Beijing 100871 Peoples R China Tsinghua Univ State Key Lab Automot Safety & Energy Beijing 100084 Peoples R China Nanjing Univ Informat Sci & Technol Collaborat Innovat Ctr Atmospher Environm & Equip Nanjing 210044 Peoples R China Univ Gothenburg Dept Chem & Mol Biol Atmospher Sci SE-41296 Gothenburg Sweden

The phase states of primarily emitted and secondarily formed aerosols from gasoline vehicle exhausts were investigated by quantifying the particle rebound fraction (f). The rebound behaviors of gasoline vehicle emission-related aerosols varied with engines, fuel types, and photochemical aging time, showing distinguished differences from biogenic secondary organic aerosols. The nonliquid-to-liquid phase transition of primary aerosols emitted from port fuel injection (PFI) and gasoline direct injection (GDI) vehicles started at a relative humidity (RH) = 50 and 60%, and liquefaction was accomplished at 60 and 70%, respectively. The RH at which f declined to 0.5 decreased from 70 to 65% for the PFI case with 92# fuel, corresponding to the photochemical aging time from 0.37 to 4.62 days. For the GDI case, such RH enhanced from 60 to 65%. Our results can be used to imply the phase state of traffic-related aerosols and further understand their roles in urban atmospheric chemistry. Taking Beijing, China, as an example, traffic-related aerosols were mainly nonliquid during winter with the majority ambient RH below 50%, whereas they were mostly liquid during the morning rush hour of summer, and traffic-related secondary aerosols fluctuated between nonliquid and liquid during the daytime and tended to be liquid at night with increased ambient RH.

关键词： Physiology Fossil fuels aerosols Oxidation Phase transitions

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Atmospheric Age Distribution of Primary and Secondary Inorganic aerosols in a Polluted Atmosphere

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ENVIRONMENTAL SCIENCE & TECHNOLOGY 2021年第9期55卷 5668-5676页

作者： Ying, Qi Zhang, Jie Zhang, Hongliang Hu, Jianlin Kleeman, Michael J. Texas A&M Univ Zachry Dept Civil & Environm Engn College Stn TX 77843 USA Fudan Univ Dept Environm Sci & Engn Shanghai 200438 Peoples R China Jiangsu Key Lab Atmospher Environm Monitoring & P Nanjing 210044 Jiangsu Peoples R China Collaborat Innovat Ctr Atmospher Environm & Equip Nanjing 210044 Jiangsu Peoples R China Nanjing Univ Informat Sci & Technol Sch Environm Sci & Engn Nanjing 210044 Jiangsu Peoples R China Univ Calif Davis Dept Civil & Environm Engn Davis CA 95616 USA

The community multiscale air quality (CMAQ) model was modified to track the evolution of the atmospheric age (tau) distribution of primary particulate matter (PPM) and secondary inorganic aerosol components (nitrate, sulfate, and ammonium ion, NSA). The modified CMAQ gas and aerosol mechanisms represent the same species emitted at different times as an age-resolved mixture, using multiple age-tagged variables and a dynamic age-bin advancing scheme. The model was applied to study the spatial and temporal evolution of tau for PPM and NSA in January 2013 to understand the formation and regional transport of PM and the precursor gases during severe winter pollution episodes in China. The results showed that increases in PPM and NSA concentrations during high pollution periods in polluted urban areas were typically associated with increases in the mean atmospheric age ((tau) over bar) due to the accumulation of local emissions and regional transport of aged pollutants. Some of the rapid sulfate growth events at the beginning of multiday air pollution episodes were driven by regional transport of aged particles. In heavily polluted cities, while most of the monthly average PPM had tau less than 10 h, more than half of the sulfate had tau greater than 20-30 h. Regional distributions showed that very aged sulfate particles with tau > 96 h accounted for a significant portion of the total sulfate and had a very broad spatial distribution. However, aged ammonium ions had very low concentrations. Aged nitrate also had lower concentrations and more limited spatial distributions than sulfate due to differences in the atmospheric lifetime between SO2 and NOx. The estimated NOx lifetime of approximately similar to 24 h in China agrees with a satellite-based estimation of 21 h. Potential applications of the age distribution analysis include evaluating the impacts of meteorology on air quality and developing short-term emission control strategies.

关键词： Anions Environmental pollution aerosols Environmental modeling Particulate matter

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Vertical Distributions of Primary and Secondary aerosols in Urban Boundary Layer: Insights into Sources, Chemistry, and Interaction with Meteorology

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ENVIRONMENTAL SCIENCE & TECHNOLOGY 2021年第8期55卷 4542-4552页

作者： Lei, Lu Sun, Yele Ouyang, Bin Qiu, Yanmei Xie, Conghui Tang, Guiqian Zhou, Wei He, Yao Wang, Qingqing Cheng, Xueling Fu, Pingqing Wang, Zifa Chinese Acad Sci Inst Atmospher Phys State Key Lab Atmospher Boundary Layer Phys & Atm Beijing 100029 Peoples R China Univ Chinese Acad Sci Coll Earth & Planetary Sci Beijing 100049 Peoples R China Shenzhen Cambri Environm Technol Co Ltd Shenzhen 518048 Peoples R China Univ Lancaster Lancaster Environm Ctr Lancaster LA1 4YQ England Tianjin Univ Inst Surface Earth Syst Sci Tianjin 300072 Peoples R China Chinese Acad Sci Ctr Excellence Reg Atmospher Environm Inst Urban Environm Xiamen 361021 Peoples R China

Vertical measurements are essential for the characterization of aerosol and boundary layer interactions;yet, our knowledge of vertical profiles of primary and secondary aerosol species in megacities is limited. Here, we conducted comprehensive vertical measurements of aerosol particle composition on a 325 m meteorological tower with two aerosol chemical speciation monitors in winter in urban Beijing. The simultaneous measurements at ground level, 140, and 240 m illustrated similar aerosol bulk composition at these three heights. However, the vertical ratios varied significantly among different aerosol species. Particularly, the vertical ratios of the aqueous phase and photochemical-related secondary organic aerosol (SOA) (aqOOA/OOA) decreased significantly, accompanied by the increases in ratios of secondary to primary OA, highlighting different chemical properties of OA between ground level and aloft, and the large impacts of vertical changes in meteorology and gaseous precursors on SOA formation. The vertical changes in NO3/SO4 ratios, however, were mostly insignificant, likely due to the low relative humidity and aerosol water content that inhibited nocturnal heterogeneous reactions in the residual layer. Considerable increases in the ratios of 240 m to ground level in the early morning were also observed for most aerosol species, demonstrating impact of residual layer on the air pollution of 2nd day.

关键词： Atmospheric chemistry Anions Layers aerosols Particulate matter

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Classification of atmospheric aerosols and clouds by use of dual-polarization lidar measurements

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OPTICS EXPRESS 2021年第15期29卷 23461-23476页

作者： Qi, Siqi Huang, Zhongwei Ma, Xiaojun Huang, Jianping Zhou, Tian Zhang, Shuang Dong, Qingqing Bi, Jianrong Shi, Jinsen Lanzhou Univ Coll Atmospher Sci Collaborat Innovat Ctr West Ecol Safety CIWES Lanzhou 73000 Peoples R China Fudan Univ Dept Atmospher & Ocean Sci Shanghai 200438 Peoples R China Fudan Univ Inst Atmospher Sci Shanghai 200438 Peoples R China Zhuhai Fudan Innovat Inst Innovat Ctr Ocean Atmosphere Syst Observat & Pred Zhuhai Guangdong Peoples R China

Accurate identification of aerosols and cloud from remote sensing observations is of importance for quantitatively evaluating their radiative forcing and related impacts. Even though polarization lidar has exhibited a unique advantage of classifying atmospheric aerosols and clouds over the past several decades, polarization measurements are often achieved at one wavelength (UV or VIS) using laser remote sensing. To better identify the types of aerosols and clouds, we developed a ground-based dual-polarization lidar system that can simultaneously detect polarization measurements at wavelengths of 355 nm and 532 nm. Our results show that the volume depolarization ratios (VDRs) at 355 nm and 532 nm markedly differ for typical types of aerosols and clouds in the atmosphere. For non-spherical particles, the ratio of VDRs at 532 tun and 355 nm are 2.87 +/- 1.35 for ice cloud and 1.51 +/- 0.29 for dust-dominated aerosols, respectively. However, for spherical particles, the ratios are 0.43 +/- 0.26 for water cloud and 0.56 +/- 0.05 for air pollutants. Consequently, we proposed a simple reliable method for classifying atmospheric aerosols and clouds from polarization measurements observed by the developed lidar system. The proposed method first distinguishes clouds from aerosols using a combination of the color ratio (CR, 532 nm/355 nm) and attenuated backscattering coefficients (ABC) at 532 nm. Then, subtypes of clouds and aerosols are identified based on the ratio of VDRs at 532 nm and 355 nm. The results showed that dual-polarization lidar measurements can remarkably improve the classification of atmospheric aerosols and clouds, compared with results using a traditional method. This study illustrates that more information on atmospheric aerosols and clouds can be obtained from polarization measurements at multiple wavelengths by active remote sensing. (C) 2021 Optical Society of America under the terms of the OSA Open Access Publishing Agreement

关键词： Aerosol effects aerosols Atmospheric measurement Atmospheric observation Atmospheric scattering Remote sensing

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