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Hygroscopicity and Compositional Evolution of Atmospheric aerosols Containing Water-Soluble Carboxylic Acid Salts and Ammonium Sulfate: Influence of Ammonium Depletion

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ENVIRONMENTAL SCIENCE & TECHNOLOGY 2019年第11期53卷 6225-6234页

作者： Wang, Na Jing, Bo Wang, Pan Wang, Zhen Li, Jiarong Pang, Shufeng Zhang, Yunhong Ge, Maofa Beijing Inst Technol Sch Chem & Chem Engn Beijing 100081 Peoples R China Chinese Acad Sci CAS Res Educ Ctr Excellence Mol Sci State Key Lab Struct Chem Unstable & Stable Speci Inst Chem Beijing 100190 Peoples R China Univ Chinese Acad Sci Beijing 100049 Peoples R China Chinese Acad Sci Inst Urban Environm Ctr Excellence Reg Atmospher Environm Xiamen 361021 Fujian Peoples R China

Water-soluble organic acid salts are important components of atmospheric aerosols. Despite their importance, it is still not clear how water-soluble organic acid salts influence interactions between aerosols and water vapor in the atmosphere. In this study, the hygroscopic behaviors and chemical compositions of aerosol particles containing water-soluble organic acid salt ((CH2)(n)(COONa)(2), n = 0, 1, 2) and (NH4)(2)SO4 were measured using in situ attenuated total reflectance Fourier transform infrared spectroscopy (ATR-FTIR). The ammonium depletion due to release of gaseous NH3 was found in mixed aerosols composed of (CH2)(n)(COONa)(2) (n = 1, 2) and (NH4)(2)SO4 upon dehydration. The ammonium loss could modify the aerosol composition, resulting in the formation of corresponding organic acid and monosodium dicarboxylate in mixed particles with high and low (NH4)(2)SO4 content, respectively. Due to the weaker hydrolysis of oxalate anions, the ammonium depletion was not observed for the Na2C2O4/(NH4)(2)SO4 mixtures. The changes in the particle composition led to the decreased water uptake upon hydration as compared to that upon dehydration. Our findings reveal that interactions between water-soluble organic acid salts and (NH4)(2)SO4 in aqueous aerosols may affect the repartition of NH3 between the condensed and gas phases, thus modifying composition and physicochemical properties of aerosols as well as relevant chemical processes.

关键词： Organic acids Anions Dehydration aerosols Cations

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Sources and dry deposition of carbonaceous aerosols over the coastal East China Sea: Implications for anthropogenic pollutant pathways and deposition

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ENVIRONMENTAL POLLUTION 2019年 245卷 771-779页

作者： Wang, Fengwen Feng, Ting Guo, Zhigang Li, Yuanyuan Lin, Tian Rose, Neil L. Chongqing Univ State Key Lab Coal Mine Disaster Dynam & Control Chongqing 400030 Peoples R China Fudan Univ Shanghai Key Lab Atmospher Particle Pollut & Prev Dept Environm Sci & Engn Shanghai 200438 Peoples R China Chongqing Univ Coll Resources & Environm Sci Dept Environm Sci Chongqing 400030 Peoples R China Chinese Acad Sci Inst Geochem State Key Lab Environm Geochem Guiyang 550002 Guizhou Peoples R China UCL Environm Change Res Ctr Gower St London WC1E 6BT England

75 paired TSP and PM2.5 samples were collected over four seasons on Huaniao Island (HNI), an island that lies downwind of continental pollutants emitted from mainland China to the East China Sea (ECS). These samples were analyzed for organic carbon (OC) and elemental carbon (EC), with a special focus on char-EC (char) and soot-EC (soot), to understand their sources, and the scale and extent of pollution and dry deposition over the coastal ECS. The results showed that char concentrations in PM2.5 and TSP averaged from 0.13 to 1.01 and 0.31-1.44 mu g m(-3);while for soot, they were from 0.03 to 0.21 and 0.16-0.56 mu g m(-3), respectively. 69.0% of the char and 36.4% of the soot were present in PM2.5. The char showed apparent seasonal variations, with highest concentrations in winter and lowest in summer;while soot displayed maximum concentrations in fall and minimum in summer. The char/soot ratios in PM2.5 averaged from 3.29 to 17.22;while for TSP, they were from 1.20 to 7.07. Both of the ratios in PM2.5 and TSP were highest in winter and lowest in fall. Comparisons of seasonal variations in OC/EC and char/soot ratios confirmed that char/soot may be a more effective indicator of carbonaceous aerosol source identification than OC/EC. Annual average atmospheric dry deposition fluxes of OC and EC into ECS were estimated to be 229 and 107 mu g m(-2) d(-1), respectively, and their deposition fluxes significantly increased during episodes. It was estimated that the loadings of OC + EC and EC accounted for 1.3% and 4.1% of the total organic carbon and EC in ECS surface sediments, respectively, implying a relatively small contribution of OC and EC dry deposition to organic carbon burial. This finding also indicates a possibly more important contribution of wet deposition to organic carbon burial in sediments of ECS, and this factor should be considered for future study. (C) 2018 Elsevier Ltd. All rights reserved.

关键词： Organic carbon Elemental carbon Char and soot aerosols Sources Dry deposition East China Sea

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Investigation of various aerosols over different locations in South Africa using satellite, model simulations and LIDAR

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METEOROLOGICAL APPLICATIONS 2019年第2期26卷 275-287页

作者： Shikwambana, Lerato Sivakumar, Venkataraman Univ KwaZulu Natal Sch Chem & Phys Durban South Africa South African Natl Space Agcy Div Space Sci Hermanus South Africa

Decadal studies (2004-2014) of various aerosols were carried out over South Africa (SA) using various satellite data and model simulations. The aerosols investigated included black carbon (BC), sulphate, dust and marine aerosols. BC aerosols were observed to be dominant in the northeastern parts of SA while sulphate aerosols were dominant in eastern parts of the country. Seasonal studies revealed that BC aerosols were more dominant in the eastern parts of SA during spring and less dominant in autumn. Sulphate also showed dominance in the eastern parts of SA during summer and less dominance in winter. The high sulphate concentration in summer is a result of an increase in relative humidity which favours the production of sulphates. Air masses from the north and northeastern parts of the subcontinent were responsible for the transport of BC resulting from biomass burning into SA. The Goddard Chemistry Aerosol Radiation and Transport model indicated that there was no significant change in the sulphate aerosol trends from 2004 to 2007. The highest sulphate aerosol levels were observed in the summer whilst the lowest sulphate aerosol levels were observed in winter. The Council for Scientific and Industrial Research (CSIR) Light Detection and Ranging (LIDAR) was used to carry out measurements in Lephalale during July 10-18, 2014. Aerosol extinction co-efficient profiles were retrieved by the CSIR mobile LIDAR and were compared to aerosol extinction co-efficient profiles retrieved from the Cloud-Aerosol LIDAR and Infrared Pathfinder Satellite Observations (CALIPSO). The aerosol extinction co-efficients of 0.26 and 0.17/km on July 14 and 16, 2014, respectively could be identified as dust aerosols.

关键词： aerosols AOD LIDAR MERRA-2

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Effects of Atmospheric Processing on the Oxidative Potential of Biomass Burning Organic aerosols

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ENVIRONMENTAL SCIENCE & TECHNOLOGY 2019年第12期53卷 6747-6756页

作者： Wong, Jenny P. S. Tsagkaraki, Maria Tsiodra, Irini Mihalopoulos, Nikolaos Violaki, Kalliopi Kanakidou, Maria Sciare, Jean Nenes, Athanasios Weber, Rodney J. Georgia Inst Technol Earth & Atmospher Sci Atlanta GA 30331 USA Univ Crete Dept Chem Environm Chem Proc Lab Iraklion 70013 Crete Greece Natl Observ Athens IERSD Palea Penteli 15236 Greece Ecole Polytech Fed Lausanne Sch Architecture Civil & Environm Engn Lab Atmospher Processes & Their Impacts CH-1015 Lausanne Switzerland Georgia Inst Technol Sch Chem & Biomol Engn Atlanta GA 30331 USA Cyprus Inst Energy Environm & Water Res CY-1645 Nicosia Cyprus

Oxidative potential (OP), which is the ability of certain components in atmospheric particles to generate reactive oxidative species (ROS) and deplete antioxidants in vivo, is a prevailing toxicological mechanism underlying the adverse health effects associated with exposure to ambient aerosols. While previous studies have identified the high OP of fresh biomass burning organic aerosols (BBOA), it remains unclear how it evolves throughout atmospheric transport. Using the dithiothreitol (DTT) assay as a measure of OP, a combination of field observations and laboratory experiments is used to determine how atmospheric aging transforms the intrinsic OP (OPmassDTT) of BBOA. For ambient BBOA collected during the fire seasons in Greece, OPmassDTT was observed to increase by a factor of 2.1 +/- 0.9 for samples of atmospheric ages up to 68 h. Laboratory experiments indicate that aqueous photochemical aging (aging by UVB and UVA photolysis;as well as 01-1 oxidation), as well as aging by ozone and atmospheric dilution can transform the OPmassDTT of the water-soluble fraction of wood smoke within 2 days of atmospheric transport. The results from this work suggest that the air quality impacts of biomass burning emissions can extend beyond regions near fire sites and should be accounted for.

关键词： Physiology Redox reactions Biomass aerosols Particulate matter

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Characterization of atmospheric aerosols and source apportionment analyses in urban Harbin, northeast China

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INFRARED PHYSICS & TECHNOLOGY 2019年 103卷 103109-000页

作者： Chen, Qi-Xiang Huang, Chun-Lin Xiao, Ting Yuan, Yuan Mao, Qian-Jun Tan, He-Ping Harbin Inst Technol Minist Ind & Informat Technol Key Lab Aerosp Thermophys Harbin 150001 Heilongjiang Peoples R China Wuhan Univ Sci & Technol Sch Urban Construct 2 Huangjiaxi St Wuhan 063009 Hubei Peoples R China Harbin Inst Technol Sch Mech Engn & Automat 6 Pingshan Rd Shenzhen 518055 Guangdong Peoples R China

Detailed knowledge of aerosol chemical characteristics and emission sources play a key role in climate and human health. In this study, we collected the atmospheric aerosol particles in urban Harbin, the northernmost provincial capital in northeast China, using an ambient sampler during the period from April to June 2017. Morphological and chemical composition analyses of collected particles were performed using a Fourier transform infrared spectrometer (FTIR), an X-ray fluorescence spectrometer (XRF), and a scanning electron microscope equipped with an energy dispersion spectrum (SEM-EDS). Emission sources of these aerosol particles were determined via an enrichment factor analysis and then their variation were further discussed. During the studying period, the atmospheric particles were mainly composed of organics, inorganic ions and oxides with 20 elements (i.e., C, O, Na, Mg, Al, Si, P, and S) observed. Among the detected elements, Cr, Ni, Cu, Br, and Zn were found to be enriched, indicating considerable anthropogenic influence during high pollution days. In early April, most of the aerosol particles were emitted from coal-fired boilers and coal-fired power plants;in early May, they mainly originated from soil dust and dust, traffic, and industry emissions;and in late May and June, traffic and industry became the major aerosol sources over Harbin.

关键词： aerosols Particulate matter Source apportioning Emission variation Northeast China

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Nitrogen Speciation and Isotopic Composition of aerosols Collected at Himalayan Forest (3326 m a.s.l.): Seasonality, Sources, and Implications

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ENVIRONMENTAL SCIENCE & TECHNOLOGY 2019年第21期53卷 12247-12256页

作者： Bhattarai, Hemraj Zhang, Yan-Lin Pavuluri, Chandra Mouli Wan, Xin Wu, Guangming Li, Peilin Cao, Fang Zhang, Wenqi Wang, Yongjie Kang, Shichang Ram, Kirpa Kawamura, Kimitaka Ji, Zhenming Widory, David Cong, Zhiyuan Chinese Acad Sci Inst Tibetan Plateau Res Key Lab Tibetan Environm Changes & Land Surface P Beijing 100101 Peoples R China Nanjing Univ Informat Sci & Technol Yale NUIST Ctr Atmospher Environm Nanjing 210044 Jiangsu Peoples R China Chinese Acad Sci Northwest Inst Ecoenvironm & Resources State Key Lab Cryospher Sci Lanzhou 730000 Gansu Peoples R China Tianjin Univ Inst Surface Earth Syst Sci Tianjin 300072 Peoples R China Chubu Univ Chubu Inst Adv Studies Kasugai Aichi 4878501 Japan Univ Chinese Acad Sci Beijing 100049 Peoples R China CAS Ctr Excellence Tibetan Plateau Earth Sci Beijing 100101 Peoples R China Banaras Hindu Univ Inst Environm & Sustainable Dev Varanasi 221005 Uttar Pradesh India Sun Yat Sen Univ Guangdong Prov Key Lab Climate Change & Nat Disas Sch Atmospher Sci Guangzhou 510275 Guangdong Peoples R China Univ Quebec Montreal UQAM Geotop 201 Ave President Kennedy Montreal PQ H2X 3Y7 Canada

Nitrogenous aerosols are ubiquitous in the environment and thus play a vital role in the nutrient balance as well as the Earth's climate system. However, their abundance, sources, and deposition are poorly understood, particularly in the fragile and ecosensitive Himalayan and Tibetan Plateau (HTP) region. Here, we report concentrations of nitrogen species and isotopic composition (delta N-15) in aerosol samples collected from a forest site in the HTP (i.e., Southeast Tibet). Our results revealed that both organic and inorganic nitrogen contribute almost equally with high abundance of ammonium nitrogen (NH4+-N) and water-insoluble organic nitrogen (WION), contributing similar to 40% each to aerosol total nitrogen (TN). The concentrations and delta N-15 exhibit a significant seasonality with similar to 2 times higher in winter than in summer with no significant diurnal variations for any species. Moreover, winter aerosols mainly originated from biomass burning emissions from North India and East Pakistan and reached the HTP through a long-range atmospheric transport. The TN dry deposition and total deposition fluxes were 2.04 kg ha(-1) yr(-1) and 6.12 kg ha(-1) yr(-1) respectively. Our results demonstrate that the air contamination from South Asia reach the HTP yand is most likely impacting the high altitude ecosystems in an accepted scenario of increasing emissions over South Asia.

关键词： Redox reactions Biomass aerosols Deposition Nitrogen

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Transboundary transport of biomass burning aerosols and photochemical pollution in the Orinoco River Basin

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ATMOSPHERIC ENVIRONMENT 2019年 205卷 1-8页

作者： Hernandez, Andrea J. Morales-Rincon, Luis A. Wu, Dien Mallia, Derek Lin, John C. Jimenez, Rodrigo Univ Nacl Colombia Dept Chem & Environm Engn Air Qual Res Grp Bogota 111321 DC Colombia Univ Utah Dept Atmospher Sci Land Atmosphere Interact Res Grp Salt Lake City UT 84112 USA

The "Llanos" is a complex savanna ecosystem that occupies most of the Orinoco River Basin, from the Colombian Andes foothills almost to the Orinoco River Delta at the Atlantic Ocean in Venezuela. It undergoes periodic, human-Induced and natural biomass burning during the thy season, which is shorter in Colombia. Northeast trade winds that prevail during the dry season can transport biomass burning plumes from Venezuela to Colombia, even during the Colombian Llanos wet season. Our analysis is based on ambient air measurements at two middle size Colombian Llanos cities located 266 km apart, during April-May 2015, right after the end of the dry season in Colombia, but when there was still high fire activity in Venezuela. Observed 24-h averaged PM10 concentrations in the two cities were unexpectedly high (up to 112 mu g/m(3)), particularly when considering their relatively small size, and low industrial and road traffic activity, and their trends were very similar, which indicates a common remote source. Ozone enhancements of up to similar to 94 ppbv (*** average) were also observed. A reasonably good correlation was found between PM(10 )and a proxy of fire emissions within footprints calculated using the Stochastic Time-Inverted Lagrangian Transport model. There is currently no permanent air quality surveillance system in the Colombian Llanos. Our findings imply that such a system should be established and incorporate near real-time, synoptic scale biomass burning remote sensing information.

关键词： Biomass burning Orinoco River Basin Transboundary pollution aerosols Ozone Lagrangian simulation

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Understanding Hygroscopic Nucleation of Sulfate aerosols: Combination of Molecular Dynamics Simulation with Classical Nucleation Theory

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JOURNAL OF PHYSICAL CHEMISTRY LETTERS 2019年第5期10卷 1126-1132页

作者： Zhao, Zheng Kong, Kewei Wang, Shixian Zhou, Yingcheng Cheng, Daojian Wang, Wenchuan Zeng, Xiao Cheng Li, Hui Beijing Univ Chem Technol Beijing Adv Innovat Ctr Soft Matter Sci & Engn Beijing 100029 Peoples R China Univ Nebraska Lincoln Dept Chem Lincoln NE 68588 USA

We present a combined molecular dynamics (MD) and classical nucleation theory (CNT) approach to address many issues regarding the nucleation of inorganic aerosols. By taking parameters from MD simulations, we find the CNT predicts fairly reasonable free-energy profiles for the hygroscopic nucleation of aerosols. Moreover, we find that the ionization of sulfates can play a key role in stabilizing aqueous clusters and that both the size of the critical nucleus and the nucleation barrier can be significantly lowered by the H2SO4 and NH4HSO4, whereas the effect of NH3 on nucleation is negligible. NH4HSO4 provides stronger enhancement effect to aerosol formation than H2SO4. In view of the consistency between the theoretical prediction and experimental observation, the combination of MD simulation and CNT appears to be a valuable approach to gain deeper understanding of how aerosol nucleation is affected by different chemical species.

关键词： Surface tension Molecules aerosols Cluster chemistry Nucleation

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Ensembles of Global Climate Model Variants Designed for the Quantification and Constraint of Uncertainty in aerosols and Their Radiative Forcing

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JOURNAL OF ADVANCES IN MODELING EARTH SYSTEMS 2019年第11期11卷 3728-3754页

作者： Yoshioka, M. Regayre, L. A. Pringle, K. J. Johnson, J. S. Mann, G. W. Partridge, D. G. Sexton, D. M. H. Lister, G. M. S. Schutgens, N. Stier, P. Kipling, Z. Bellouin, N. Browse, J. Booth, B. B. B. Johnson, C. E. Johnson, B. Mollard, J. D. P. Lee, L. Carslaw, K. S. Univ Leeds Sch Earth & Environm Leeds W Yorkshire England Univ Leeds Natl Ctr Atmospher Sci Leeds W Yorkshire England Univ Exeter Coll Engn Math & Phys Sci Exeter Devon England UK Hadley Ctr Met Off Exeter Devon England Univ Reading Natl Ctr Atmospher Sci Reading Berks England Univ Oxford Dept Phys Atmospher Ocean & Planetary Phys Oxford England Vrije Univ Amsterdam Fac Sci Cluster Earth & Climate Amsterdam Netherlands European Ctr Medium Range Weather Forecasts Reading Berks England Univ Reading Dept Meteorol Reading Berks England Univ Exeter Ctr Geog Environm & Soc Penryn England

Tropospheric aerosol radiative forcing has persisted for many years as one of the major causes of uncertainty in global climate model simulations. To sample the range of plausible aerosol and atmospheric states and perform robust statistical analyses of the radiative forcing, it is important to account for the combined effects of many sources of model uncertainty, which is rarely done due to the high computational cost. This paper describes the designs of two ensembles of the Met Office Hadley Centre Global Environment Model-U.K. Chemistry and Aerosol global climate model and provides the first analyses of the uncertainties in aerosol radiative forcing and their causes. The first ensemble was designed to comprehensively sample uncertainty in the aerosol state, while the other samples additional uncertainties in the physical model related to clouds, humidity, and radiation, thereby allowing an analysis of uncertainty in the aerosol effective radiative forcing. Each ensemble consists of around 200 simulations of the preindustrial and present-day atmospheres. The uncertainty in aerosol radiative forcing in our ensembles is comparable to the range of estimates from multimodel intercomparison projects. The mean aerosol effective radiative forcing is -1.45 W/m(2) (credible interval of -2.07 to -0.81 W/m(2)), which encompasses but is more negative than the -1.17 W/m(2) in the 2013 Atmospheric Chemistry and Climate Model Intercomparison Project and -0.90 W/m(2) in the Intergovernmental Panel on Climate Change Fifth Assessment Report. The ensembles can be used to reduce aerosol radiative forcing uncertainty by challenging them with multiple measurements as well as to isolate potential causes of multimodel differences.

关键词： aerosols radiative forcing ERF perturbed parameter ensemble emulators uncertainty

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Dicarboxylic acids and related compounds in fine particulate matter aerosols in Huangshi, central China

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JOURNAL OF THE AIR & WASTE MANAGEMENT ASSOCIATION 2019年第4期69卷 513-526页

作者： Liu, Hongxia Kawamura, Kimitaka Kunwar, Bhagawati Cao, Junji Zhang, Jiaquan Zhan, Changlin Zheng, Jingru Yao, Ruizhen Liu, Ting Xiao, Wensheng Hubei Polytech Univ Sch Environm Sci & Engn Hubei Key Lab Mine Environm Pollut Control & Reme Huangshi Hubei Peoples R China Hokkaido Univ Inst Low Temp Sci Sapporo Hokkaido Japan Chubu Univ Chubu Inst Adv Studies Kasugai Aichi Japan Chinese Acad Sci Inst Earth Environm Key Lab Aerosol Chem & Phys Xian Shaanxi Peoples R China

PM2.5 (particulate matter with an aerodynamic diameter <2.5 mu m) samples were collected in Huangshi, central China, from March 2012 to February 2013 and were analyzed for dicarboxylic acids (diacids) and related compounds (DARCs). Oxalic acid (C-2;416 ng m(-3)) was the most abundant species, followed by phthalic (Ph;122 ng m(-3)), terephthalic (tPh;116 ng m(-3)), succinic (C-4;70.4 ng m(-3)), azelaic (C-9;67.9 ng m(-3)), and adipic (C-6;57.8 ng m(-3)) acids. Relatively high abundances of Ph and tPh differed from the distribution in urban and marine aerosols, indicating contributions from nearby anthropogenic sources. Glyoxylic acid (omega C-2;41.4 ng m(-3)) was the dominant oxoacid, followed by 9-oxononanoic (omega C-9;40.8 ng m(-3)) and pyruvic (Pyr;24.1 ng m(-3)) acids. Glyoxal (Gly;35.5 ng m(-3)) was the dominant alpha-dicarbonyl. Highest average concentrations were found for C-2, omega C-2, and C-9 in autumn, for C-4, for Pyr and C-6 in spring, for Ph, omega C-9, and Gly in summer, whereas the lowest values were observed in winter. Seasonal variations and correlation coefficients of DARCs demonstrate that both primary emissions and secondary production are important sources. Principal component analysis of selected DARCs species suggests that a mixing of air masses from anthropogenic and biogenic sources contribute to the Huangshi aerosols. Implications: Both primary emissions and secondary production are important sources of diacids and related compounds in PM2.5 from Huangshi, central China. Principal component analysis of selected diacids in Huangshi aerosols suggests that mixing of air masses from anthropogenic and biogenic sources contribute to ambient aerosols in central China.

关键词： aerosols

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