Global S&T Development Trend Analysis Platform of Resources and Environment
DOI | 10.5194/acp-17-14415-2017 |
Compositional evolution of particle-phase reaction products and water in the heterogeneous OH oxidation of model aqueous organic aerosols | |
Chim, Man Mei1; Cheng, Chiu Tung1; Davies, James F.2; Berkemeier, Thomas3; Shiraiwa, Manabu4; Zuend, Andreas5; Chan, Man Nin1,6 | |
2017-12-05 | |
发表期刊 | ATMOSPHERIC CHEMISTRY AND PHYSICS
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ISSN | 1680-7316 |
EISSN | 1680-7324 |
出版年 | 2017 |
卷号 | 17期号:23 |
文章类型 | Article |
语种 | 英语 |
国家 | Peoples R China; USA; Canada |
英文摘要 | Organic compounds present at or near the surface of aqueous droplets can be efficiently oxidized by gas-phase OH radicals, which alter the molecular distribution of the reaction products within the droplet. A change in aerosol composition affects the hygroscopicity and leads to a concomitant response in the equilibrium amount of particle-phase water. The variation in the aerosol water content affects the aerosol size and physicochemical properties, which in turn governs the oxidation kinetics and chemistry. To attain better knowledge of the compositional evolution of aqueous organic droplets during oxidation, this work investigates the heterogeneous OH-radical-initiated oxidation of aqueous methylsuccinic acid (C5H8O4) droplets, a model compound for small branched dicarboxylic acids found in atmospheric aerosols, at a high relative humidity of 85% through experimental and modeling approaches. Aerosol mass spectra measured by a soft atmospheric pressure ionization source (Direct Analysis in Real Time, DART) coupled with a high-resolution mass spectrometer reveal two major products: a five carbon atom (C-5) hydroxyl functionalization product (C5H8O5) and a C-4 fragmentation product (C4H6O3). These two products likely originate from the formation and subsequent reactions (intermolecular hydrogen abstraction and carbon-carbon bond scission) of tertiary alkoxy radicals resulting from the OH abstraction occurring at the methyl-substituted carbon site. Based on the identification of the reaction products, a kinetic model of oxidation (a two-product model) coupled with the Aerosol Inorganic-Organic Mixtures Functional groups Activity Coefficients (AIOMFAC) model is built to simulate the size and compositional changes of aqueous methylsuccinic acid droplets during oxidation. Model results show that at the maximum OH exposure, the droplets become slightly more hygroscopic after oxidation, as the mass fraction of water is predicted to increase from 0.362 to 0.424; however, the diameter of the droplets decreases by 6.1 %. This can be attributed to the formation of volatile fragmentation products that partition to the gas phase, leading to a net loss of organic species and associated particle-phase water, and thus a smaller droplet size. Overall, fragmentation and volatilization processes play a larger role than the functionalization process in determining the evolution of aerosol water content and droplet size at high-oxidation stages. |
领域 | 地球科学 |
收录类别 | SCI-E |
WOS记录号 | WOS:000417073800002 |
WOS关键词 | CLOUD CONDENSATION NUCLEI ; SITU CHEMICAL-CHARACTERIZATION ; ATMOSPHERIC AEROSOLS ; RATE CONSTANTS ; TEMPERATURE-DEPENDENCE ; HYGROSCOPIC BEHAVIOR ; THERMODYNAMIC MODEL ; DICARBOXYLIC-ACIDS ; VAPOR-PRESSURES ; GAS UPTAKE |
WOS类目 | Environmental Sciences ; Meteorology & Atmospheric Sciences |
WOS研究方向 | Environmental Sciences & Ecology ; Meteorology & Atmospheric Sciences |
引用统计 | |
文献类型 | 期刊论文 |
条目标识符 | http://119.78.100.173/C666/handle/2XK7JSWQ/21655 |
专题 | 地球科学 |
作者单位 | 1.Chinese Univ Hong Kong, Earth Syst Sci Programme, Fac Sci, Hong Kong, Hong Kong, Peoples R China; 2.Lawrence Berkeley Natl Lab, Chem Sci Div, Berkeley, CA USA; 3.Georgia Inst Technol, Sch Chem & Biomol Engn, Atlanta, GA 30332 USA; 4.Univ Calif Irvine, Dept Chem, Sch Phys Sci, Irvine, CA 92717 USA; 5.McGill Univ, Dept Atmospher & Ocean Sci, Montreal, PQ, Canada; 6.Chinese Univ Hong Kong, Inst Environm Energy & Sustainabil, Hong Kong, Hong Kong, Peoples R China |
推荐引用方式 GB/T 7714 | Chim, Man Mei,Cheng, Chiu Tung,Davies, James F.,et al. Compositional evolution of particle-phase reaction products and water in the heterogeneous OH oxidation of model aqueous organic aerosols[J]. ATMOSPHERIC CHEMISTRY AND PHYSICS,2017,17(23). |
APA | Chim, Man Mei.,Cheng, Chiu Tung.,Davies, James F..,Berkemeier, Thomas.,Shiraiwa, Manabu.,...&Chan, Man Nin.(2017).Compositional evolution of particle-phase reaction products and water in the heterogeneous OH oxidation of model aqueous organic aerosols.ATMOSPHERIC CHEMISTRY AND PHYSICS,17(23). |
MLA | Chim, Man Mei,et al."Compositional evolution of particle-phase reaction products and water in the heterogeneous OH oxidation of model aqueous organic aerosols".ATMOSPHERIC CHEMISTRY AND PHYSICS 17.23(2017). |
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