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Transport of indoor aerosols to hidden interior spaces

AEROSOL SCIENCE AND TECHNOLOGY 2020年第1期54卷 94-110页

作者： Tang, Mengjia Zhu, Ningling Kinney, Kerry Novoselac, Atila Univ Texas Austin Dept Civil Architectural & Environm Engn 1 Univ Stn C1752 Austin TX 78712 USA

Most studies on indoor aerosols have focused on the open spaces within buildings that are visible to occupants, while the hidden spaces in buildings receive much less attention. Indeed, little is known about the extent to which indoor aerosols are transported into closets, cabinets and drawers. aerosols deposited in these hidden spaces serve as a reservoir for particulate matter with the potential for resuspension within homes. To investigate aerosol transport to indoor hidden spaces, a series of experiments were conducted in a full-scale test house. Specifically, aerosols released indoors were tracked using a fluorometric method and the air circulation between the open and hidden spaces were measured using tracer gas techniques. The results show that momentum-driven flow caused by fan operation had a negligible impact on the overall air circulation between rooms and hidden spaces. Rather, the circulation was driven primarily by buoyancy forces caused by temperature differences between the hidden spaces and adjacent rooms. In the well-controlled, three-bedroom two-bathroom test house used in this study, aerosols released indoors dispersed and deposited across the open spaces and even within closets with closed doors. For more sealed spaces like closed drawers within closed cabinets, the air circulation rates between the adjacent room and hidden space were substantially lower and a much lower fraction of the indoor aerosols deposited in these areas. Nevertheless, the results indicate that at least one percent of the indoor aerosol source penetrated into the most remote indoor hidden spaces. Copyright (c) 2019 American Association for Aerosol Research

关键词： aerosols

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In Situ Measurements of Molecular Markers Facilitate Understanding of Dynamic Sources of Atmospheric Organic aerosols

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ENVIRONMENTAL SCIENCE & TECHNOLOGY 2020年第18期54卷 11058-11069页

作者： Lyu, Xiaopu Guo, Hai Yao, Dawen Lu, Haoxian Huo, Yunxi Xu, Wen Kreisberg, Nathan Goldstein, Allen H. Jayne, John Worsnop, Douglas Tan, Yan Lee, Shun-Cheng Wang, Tao Hong Kong Polytech Univ Dept Civil & Environm Engn Hong Kong Peoples R China Aerodyne Res Inc Ctr Aerosol & Cloud Chem Billerica MA 01821 USA Aerosol Dynam Inc Berkeley CA 94710 USA Univ Calif Berkeley Dept Environm Sci Policy & Management Berkeley CA 94720 USA Univ Calif Berkeley Dept Civil & Environm Engn Berkeley CA 94720 USA

Reducing the amount of organic aerosol (OA) is crucial to mitigation of particulate pollution in China. We present time and air-origin dependent variations of OA markers and source contributions at a regionally urban background site in South China. The continental air contained primary OA markers indicative of source categories, such as levoglucosan, fatty acids, and oleic acid. Secondary OA (SOA) markers derived from isoprene and monoterpenes also exhibited higher concentrations in continental air, due to more emissions of their precursors from terrestrial ecosystems and facilitation of anthropogenic sulfate for monoterpenes SOA. The marine air and continental-marine mixed air had more abundant hydroxyl dicarboxylic acids (OHDCA), with anthropogenic unsaturated organics as potential precursors. However, OHDCA formation in continental air was likely attributable to both biogenic and anthropogenic precursors. The production efficiency of OHDCA was highest in marine air, related to the presence of sulfur dioxide and/or organic precursors in ship emissions. Regional biomass burning (BB) was identified as the largest contributor of OA in continental air, with contributions fluctuating from 8% to 74%. In contrast, anthropogenic SOA accounted for the highest fraction of OA in marine (37 +/- 4%) and mixed air (31 +/- 3%), overriding the contributions from BB. This study demonstrates the utility of molecular markers for discerning OA pollution sources in the offshore marine atmosphere, where continental and marine air pollutants interact and atmospheric oxidative capacity may be enhanced.

关键词： Atmospheric chemistry Anions Precursors aerosols Particulate matter

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Effects of atmospheric aerosols on terrestrial carbon fluxes and CO2 concentrations in China

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ATMOSPHERIC RESEARCH 2020年 237卷 104859-104859页

作者： Xie, Xiaodong Wang, Tijian Yue, Xu Li, Shu Zhuang, Bingliang Wang, Minghuai Nanjing Univ Sch Atmospher Sci Nanjing 210023 Peoples R China NUIST Collaborat Innovat Ctr Atmospher Environm & Equip Sch Environm Sci & Engn Jiangsu Key Lab Atmospher Environm Monitoring & P Nanjing 210044 Peoples R China

Atmospheric aerosols have contributed to the terrestrial carbon cycle through diffuse radiation fertilization effect and hydrometeorological feedbacks. Subsequently, perturbations in terrestrial carbon sink alter atmospheric carbon dioxide (CO2) concentrations and influence future climate change. Here, we use a regional climate model, RegCM4, coupled with the Yale Interactive terrestrial Biosphere model (YIBs) to assess the effects of the current aerosol loading on terrestrial carbon fluxes and atmospheric CO2 concentrations during 2006-2015 over China. We found that aerosols enhance gross primary production (GPP) by 0.36 Pg C yr(-1) (5%), which primarily stems from Southwest and Southeast China. Meanwhile, the aerosol-induced diffuse fraction (DF) increase, surface cooling and vapor pressure deficit (VPD) decrease together lead to a - 0.06 Pg C yr(-1) (21%) reduction in the net ecosystem exchange (NEE). Among them, aerosol-induced DF increment is found to be the dominant contributor, which covers similar to 59-62% of China's land area. The effects of aerosols on GPP and NEE are more evident in the growing season, with maximum effects occurring in July and August, respectively. Moreover, the terrestrial carbon sink enhancement due to aerosols further results in a significant decline in CO2 concentrations, with a large reduction (> 2 ppm) found in southern and eastern parts of China during the summer. Our results highlight the importance of understanding the interactions among aerosol pollution, climate change, and the global carbon cycle.

关键词： aerosols Diffuse radiation fertilization Terrestrial carbon fluxes Carbon dioxide China

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Molecular characteristics of water-soluble dicarboxylic acids, ω-oxocarboxylic acids, pyruvic acid and α-dicarbonyls in the aerosols from the eastern North Pacific

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MARINE CHEMISTRY 2020年 224卷 103812-103812页

作者： Hoque, Mir Md Mozammal Kawamura, Kimitaka Nagayama, Tomohiro Kunwar, Bhagawati Peltzer, Edward T. Gagosian, Robert B. Hokkaido Univ Inst Low Temp Sci N19 W8 Sapporo Hokkaido Japan Mawlana Bhashani Sci & Technol Univ Dept Environm Sci & Resource Management Tangail 1902 Bangladesh Chubu Univ Chubu Inst Adv Studies 1200 Matsumoto Cho Kasugai Aichi Japan Tokyo Metropolitan Univ Dept Chem Hachioji Tokyo Japan Woods Hole Oceanog Inst Marine Chem & Geochem Dept Woods Hole MA 02543 USA Monterey Bay Aquarium Res Inst Moss Landing CA USA

Aerosol samples (n = 14), collected over the eastern North Pacific (ENP, 27-52 degrees N and 150-172 degrees W), were studied for dicarboxylic acids (hereafter diacids, C-2-C-10), omega-oxoacids, pyruvic acid, and alpha-dicarbonyls as well as water-soluble organic carbon (WSOC) and total nitrogen (WSTN). We found diacids as the most abundant compound class followed by omega-oxoacids and alpha-dicarbonyls. Molecular distributions of diacids were characterized by the predominance of oxalic (C-2) (58%) acid followed by malonic (C-3) (15%) and succinic (C-4) (13.5%) acids. However, we found a predominance of C-4 over C-3 in five samples, where 4-oxobutanoic acid (omega C-4) was the most abundant omega-oxoacid species (34.6% of its class). Moreover, a strong correlation (r(2) = 0.72) was obtained between (DC4 and C-4 in those samples, suggesting that high abundances of C-4 are associated with sea-to-air emission of unsaturated fatty acids and their further photochemical processing. Good relationships between C-2 and C-3 (r(2) = 0.88) and C-3 and C-4 (r(2) = 0.79) in the marine aerosols further suggest that C-2 is produced via photochemical degradation of C-3 and C-4 over the ENP. WSOC and WSTN showed higher abundances in the longitudinal transect of 165-172 degrees W, where omega-oxoacids were abundantly detected. This study demonstrates that atmospheric levels of water-soluble organic aerosols in the ENP are largely regulated by the primary productivity followed by sea-to-air emissions of unsaturated fatty acids and isoprene and the subsequent photochemical oxidation.

关键词： aerosols Diacids Oxalic acid Succinic acid 4-oxobutanoic acid Sea-to-air emission Photochemical oxidation

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Potential impacts of future reduced aerosols on internal dynamics characteristics of precipitation based on model simulations over southern China

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PHYSICA A-STATISTICAL MECHANICS AND ITS APPLICATIONS 2020年 545卷 123808-123808页

作者： Lei, Yadong Zhang, Feng Miao, Lijuan Yu, Qiu-Run Duan, Mingkeng Fraedrich, Klaus Yu, Zifeng Nanjing Univ Informat Sci & Technol Joint Int Res Lab Climate & Environm Change ILCEC Key Lab Meteorol Disaster Minist Educ KLMECollaborat Innovat Ctr Forecast Nanjing 210044 Peoples R China Chinese Acad Sci Climate Change Res Ctr Inst Atmospher Phys Beijing 100029 Peoples R China Chinese Acad Meteorol Sci State Key Lab Severe Weather Beijing 100081 Peoples R China Nanjing Univ Informat Sci & Technol Collaborat Innovat Ctr Forecast & Evaluat Meteoro Sch Geog Sci Nanjing 210044 Peoples R China Max Planck Inst Meteorol D-20146 Hamburg Germany China Meteorol Adm Shanghai Typhoon Inst Shanghai 200030 Peoples R China

In this study, the scaling behaviors of precipitation records over southern China are investigated by using the detrended fluctuation analysis (DFA) method. It is found that the precipitation records over southern China exhibit relatively weak long-term correlation characteristics. The scaling exponents in coastal areas are close to 0.6 showing long-term correlation while in inland areas, uncorrelation can be found with the scaling exponents close to 0.5. Based on the long-term correlation characteristics of the observed precipitation records, the performance of the Community Earth System Model (CESM1) in simulating precipitation over southern China is evaluated and the results show that the CESM1 can simulate the internal dynamics characteristics of precipitation series in southern China. As indicated by the DFA results of simulated precipitation data from CESM1, the long-term correlation of precipitation records during the late-21st century (2071-2100) will increase in the Huai river basin under the RCP8.5 simulation scenario in summer and decrease in most regions of southern China under both the RCP8.5 and RCP8.5_FixA scenarios in comparison with the present condition (1987-2016). Additionally, the differences of precipitation scaling exponents between the RCP8.5 and RCP8.5_FixA simulation scenarios further indicate that the future reduced aerosols emissions will contribute to strengthening the long-term correlation of precipitation records in the Huai river basin in summer. Compared to present condition, the precipitation scaling exponents will increase by more than 0.1 during the late-21st century. (C) 2019 Elsevier B.V. All rights reserved.

关键词： Precipitation aerosols Detrended fluctuation analysis (DFA)

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Natural and anthropogenic radionuclides on aerosols in Bratislava air

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JOURNAL OF RADIOANALYTICAL AND NUCLEAR CHEMISTRY 2020年第1期325卷 245-252页

作者： Sykora, Ivan Povinec, Pavel P. Comenius Univ Fac Math Phys & Informat Dept Nucl Phys & Biophys Mlynska Dolina F-1 Bratislava 84248 Slovakia

Variations of cosmogenic (Be-7), primordial (K-40), radiogenic (Pb-210) and anthropogenic (Cs-137) in Bratislava air were studied during 2001-2019 using a weekly sampling and HPGe gamma-spectrometry. While Be-7 variations were associated with transport of air masses from the lower stratosphere to the ground level air, an inverse trend was observed for Pb-210 variations due to infiltration of radon from the soil. The Cs-137 activity concentrations (excluding the Chernobyl and Fukushima accidents) were decreasing with half-life of 1.9 years, however, during recent years they were almost constant. The increased atmospheric K-40 levels were due to soil resuspension and radionuclide transport by winds.

关键词： Radionuclides aerosols Atmospheric processes Radionuclide resuspension HPGe gamma-spectrometry

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Sensitive Research of Scattering and Absorbing aerosols on Sky Polarization Pattern

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PHOTOGRAMMETRIC ENGINEERING AND REMOTE SENSING 2020年第12期86卷 767-774页

作者： Chen, Wei Song, Ge Wang, Haozhong Zhao, Haimeng Zhu, Jianfang Zhong, Peiyi China Univ Min & Technol Coll Geosci & Surveying Engn Beijing 100083 Peoples R China Guilin Univ Aerosp Technol Guangxi Coll & Univ Key Lab Unmanned Aerial Vehic Guilin 541004 Peoples R China

Sky polarization patterns are a relatively new and interesting field of polarized remote sensing. However, most current research mainly focuses on Rayleigh scattering or different conditions of aerosol optical depth. In this study, the sky downward polarization patterns are calculated for both degree of linear polarization and angle of polarization with scattering and absorbing aerosol situations. When coarse-mode aerosol changes from scattering to absorbing, the decreasing trend in the sky downward degree-of-linear-polarization largely slcnvs down when aerosol optical depth increases. For fine-mode aerosol, on the other hand, the change of pattern is not sensitive to the absorbing property of aerosol. Sky downward angle-of-polarization patterns for different levels of aerosol optical depth and aerosol modes are similar, with little change. The results suggest that in order to accurately use sky polarization for remote sensing or bionic navigation, it is necessary to characterize aerosol microphysical properties first, especially when coarse absorbing aerosol exists.

关键词： aerosols

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Impact of a massive dust storm on the gross alpha, gross beta, ⁴⁰K, ¹³⁷Cs, ²¹⁰Pb, ⁷Be activities measured in atmospheric aerosols collected in Tenerife, Canary Islands

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ATMOSPHERIC ENVIRONMENT 2020年 239卷 117806-117806页

作者： Lopez-Perez, Maria Miguel Lorenzo-Salazar, Jose Javier Exposito, Francisco Pedro Diaz, Juan Salazar, Pedro Univ La Laguna Lab Fis Med & Radioactividad Ambiental SEGAI San Cristobal la Laguna Spain Univ La Laguna Grp Observac Tierra & Atmosfera San Cristobal la Laguna Spain Univ La Laguna Dept Med Fis & Farmacol San Cristobal la Laguna Spain

From February 22 to 24, 2020, an intense dust storm affected the Spanish archipelago of the Canary Islands. Here we assess the radiological impact on the Canary Islands population of several natural and artificial radionuclides (K-40, Cs-137, Pb-210, Be-7), and other radiological parameters (gross alpha and gross beta activity concentrations) measured in atmospheric aerosols before, during and after the dust storm. Total Suspended Matter highly correlated with PM10 (Pearson's correlation coefficient, r(o) = 0.98), showed increments ranging from 849% to 1778% against the background average levels, reaching levels of >3000 mu g m(-3). K-40 and Cs-137 radionuclides showed activity values over the minimum detection activity from January to March 2020, coupled with dust intrusion episodes during the study. This finding supports the use of these radionuclides as radiotracers for African low altitude dust intrusions occurring particularly during winter months over the Canary Islands. A high correlation between gross beta and Pb-210 activities suggests that the latter is the main source for gross beta emitters in aerosol samples collected in the study region. Pb-210 and Be-7 showed a moderate positive correlation and did not show any significant change during the storm, suggesting a similar dynamics of alpha and beta emitters in the low atmosphere. A Principal Component Analysis of these observations showed two components representing a Saharan component (based on K-40, Cs-137, gross alpha, and PM10) and a heterogeneous component representing North Atlantic and Europe air masses (based on Be-7, Pb-210, and gross beta). In addition, a K-means cluster analysis helped to disentangle the origin of air masses arriving at the archipelago. Three different clusters were identified: a continental cluster (based on gross beta, Pb-210, and Be-7 activity concentrations);an oceanic cluster (with low values of PM10 air concentrations, gross beta, gross alpha, and Pb-210, and Be-7 and K-4

关键词： Dust storm aerosols Atmospheric radionuclides PM10 Back-trajectories

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Development of a Monitoring System for Semicontinuous Measurements of Stable Carbon Isotope Ratios in Atmospheric Carbonaceous aerosols: Optimized Methods and Application to Field Measurements

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ANALYTICAL CHEMISTRY 2020年第21期92卷 14373-14382页

作者： Lin, Yu-Chi Zhang, Yan-Lin Xie, Feng Zhang, Wen-Qi Fan, Mei-Yi Lin, Zhiwei Rella, Chris W. Hoffnagle, John A. Nanjing Univ Informat Sci & Technol Yale NUIST Ctr Atmospher Environm Int Joint Lab Climate & Environm Change Nanjing 210044 Peoples R China Nanjing Univ Informat Sci & Technol Key Lab Meteorol Disaster Nanjing 210044 Peoples R China Nanjing Univ Informat Sci & Technol Minist Educ Nanjing 210044 Peoples R China Nanjing Univ Informat Sci & Technol Collaborat Innovat Ctr Forecast & Evaluat Meteoro Nanjing 210044 Peoples R China Nanjing Univ Informat Sci & Technol Sch Appl Meteorol Jiangsu Prov Key Lab Agr Meteorol Nanjing 210044 Jiangsu Peoples R China Picarro Inc Santa Clara CA 95054 USA

Carbon content constitutes a major fraction of atmospheric particulate matter (PM) and directly influences the earth's climate and human health. The stable carbon isotope ratios (delta C-13) can be used to track potential sources and atmospheric processes of carbonaceous aerosols. Previously, determination of delta C-13 was always conducted in offline carbonaceous aerosol samples. The poor time-resolution results cannot provide information regarding the temporal evolution of delta C-13 at a short-time scale. In this study, we developed a new system for online measurements of delta C-13 in atmospheric carbonaceous aerosols by combining a semicontinuous organic carbon/elemental carbon (OC/EC) analyzer and online cavity ring-down spectroscopy (CRDS) (OC/EC analyzer-CRDS). To provide better stability in the determination of delta C-13, a carrier gas with CO2 (similar to 200 ppm) in "balance gas" was used, and Keeling analysis was employed to separate the delta C-13 signal of the sample from background CO2 gas. Our results showed that the accuracy and absolute precision of the delta C-13 measurements by the OC/EC analyzer-CRDS system were better than 0.1% and 0.5%, respectively, for the samples containing carbon content more than 5 mu g. Furthermore, we employed this system to monitor delta C-13 (delta C-13-TC) in particulate total carbon (TC) with a time resolution of 2-4 h over Beijing in late summer and early autumn, 2019. During the sampling period, the TC concentrations varied from 0.1 to 12.0 mu g m(-3) with a mean value of 6.0 +/- 2.4 mu g m(-3). The delta C-13-TC ranged from -28.2 to -24.2 parts per thousand (mean value was -25.9 +/- 0.9 parts per thousand) without significant diurnal variations, suggesting similar contributing sources to TC. Comparing the delta C-13 signatures of different emissions, we found that liquid fuels and primary and secondary C-3 plants were likely the dominant sources of particulate TC. Finally, we found that atmospheric heavy precipi

关键词： Carbohydrates Carbon aerosols Particulate matter Precipitation

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Aerosol Liquid Water Promotes the Formation of Water-Soluble Organic Nitrogen in Submicrometer aerosols in a Suburban Forest

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ENVIRONMENTAL SCIENCE & TECHNOLOGY 2020年第3期54卷 1406-1414页

作者： Xu, Yu Miyazaki, Yuzo Tachibana, Eri Sato, Kei Ramasamy, Sathiyamurthi Mochizuki, Tomoki Sadanaga, Yasuhiro Nakashima, Yoshihiro Sakamoto, Yosuke Matsuda, Kazuhide Kajii, Yoshizumi Hokkaido Univ Sapporo Hokkaido Japan Natl Inst Environm Studies Tsukuba Ibaraki Japan Kyoto Univ Kyoto Japan Osaka Prefecture Univ Sakai Osaka Japan Tokyo Univ Agr & Technol Tokyo Japan

Water-soluble organic nitrogen (WSON) affects the formation, chemical transformations, hygroscopicity, and acidity of organic aerosols as well as biogeochemical cycles of nitrogen. However, large uncertainties exist in the origins and formation processes of WSON. Submicrometer aerosol particles were collected at a suburban forest site in Tokyo in summer 2015 to investigate the relative impacts of anthropogenic and biogenic sources on WSON formations and their linkages with aerosol liquid water (ALW). The concentrations of WSON (ave. 225 +/- 100 ngN m(-3)) and ALW exhibited peaks during nighttime, which showed a significant positive correlation, suggesting that ALW significantly contributed to WSON formation. Further, the thermodynamic predictions by ISORROPIA-II suggest that ALW was primarily driven by anthropogenic sulfate. Our analysis, including positive matrix factorization, suggests that aqueous-phase reactions of ammonium and reactive nitrogen with biogenic volatile organic compounds (VOCs) play a key role in WSON formation in submicrometer particles, which is particularly significant in nighttime, at the suburban forest site. The formation of WSON associated with biogenic VOCs and ALW was partly supported by the molecular characterization of WSON. The overall result suggests that ALW is an important driver for the formation of aerosol WSON through a combination of anthropogenic and biogenic sources.

关键词： Anions aerosols Nitrogen Cations Volatile organic compounds

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