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Fan R, Ma Y, Cao W, Jin S, Liu B, Wang W, Li H, Gong W. New insights into black carbon light absorption enhancement: A comprehensive analysis of two differential behaviors. ENVIRONMENTAL POLLUTION (BARKING, ESSEX : 1987) 2024; 355:124175. [PMID: 38761879 DOI: 10.1016/j.envpol.2024.124175] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/19/2024] [Revised: 04/28/2024] [Accepted: 05/15/2024] [Indexed: 05/20/2024]
Abstract
High uncertainty in optical properties of black carbon (BC) involving heterogeneous chemistry has recently attracted increasing attention in the field of atmospheric climatology. To fill the gap in BC optical knowledge so as to estimate more accurate climate effects and serve the response to global warming, it is beneficial to conduct site-level studies on BC light absorption enhancement (Eabs) characteristics. Real-time surface gas and particulate pollutant observations during the summer and winter over Wuhan were utilized for the analysis of Eabs simulated by minimum R squared (MRS), considering two distinct atmospheric conditions (2015 and 2017). In general, differences in aerosol emissions led to Eabs differential behaviors. The summer average of Eabs (1.92 ± 0.55) in 2015 was higher than the winter average (1.27 ± 0.42), while the average (1.11 ± 0.20) in 2017 summer was lower than that (1.67 ± 0.69) in winter. Eabs and RBC (representing the mass ratio of non-refractory constituents to elemental carbon) constraints suggest that Eabs increased with the increase in RBC under the ambient condition enriched by secondary inorganic aerosol (SIA), with a maximum growth rate of 70.6% in 2015 summer. However, Eabs demonstrated a negative trend against RBC in 2017 winter due to the more complicated mixing state. The result arose from the opposite impact of hygroscopic SIA and absorbing OC/irregular distributed coatings on amplifying the light absorbency of BC. Furthermore, sensitivity analysis revealed a robust positive correlation (R > 0.9) between aerosol chemical compositions (including sulfate, nitrate, ammonium and secondary organic carbon), which could be significantly perturbed by only a small fraction of absorbing materials or restructuring BC through gaps filling. The above findings not only deepen the understanding of BC, but also provide useful information for the scientific decision-making in government to mitigate particulate pollution and obtain more precise BC radiative forcing.
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Affiliation(s)
- Ruonan Fan
- State Key Laboratory of Information Engineering in Surveying, Mapping and Remote Sensing, Wuhan University, Wuhan, 430079, China
| | - Yingying Ma
- State Key Laboratory of Information Engineering in Surveying, Mapping and Remote Sensing, Wuhan University, Wuhan, 430079, China; Hubei Luojia Laboratory, Wuhan, 430079, China.
| | - Wenxiang Cao
- Eco-Environmental Monitoring Centre of Hubei Province, Wuhan, 430072, China
| | - Shikuan Jin
- State Key Laboratory of Information Engineering in Surveying, Mapping and Remote Sensing, Wuhan University, Wuhan, 430079, China
| | - Boming Liu
- State Key Laboratory of Information Engineering in Surveying, Mapping and Remote Sensing, Wuhan University, Wuhan, 430079, China
| | - Weiyan Wang
- State Key Laboratory of Information Engineering in Surveying, Mapping and Remote Sensing, Wuhan University, Wuhan, 430079, China
| | - Hui Li
- School of Electronic Information, Wuhan University, Wuhan, 430079, China
| | - Wei Gong
- School of Electronic Information, Wuhan University, Wuhan, 430079, China
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2
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Zhu Y, Liu C, Yurkin MA. Reducing shape errors in the discrete dipole approximation using effective media. OPTICS EXPRESS 2023; 31:43401-43415. [PMID: 38178434 DOI: 10.1364/oe.509479] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/19/2023] [Accepted: 11/27/2023] [Indexed: 01/06/2024]
Abstract
The discrete dipole approximation (DDA) simulates optical properties of particles with any given shape based on the volume discretization. These calculations cost a large amount of time and memory to achieve high accuracy, especially for particles with large sizes and complex geometric structures, such as mixed black-carbon aerosol particles. We systematically study the smoothing of the DDA discretization using the effective medium approximation (EMA) for boundary dipoles. This approach is tested for optical simulations of spheres and coated black-carbon (BC) aggregates, using the Lorenz-Mie and multiple-sphere T-Matrix as references. For spheres, EMA significantly improves the DDA accuracy of integral scattering quantities (up to 60 times), when the dipole size is only several times smaller than the sphere diameter. In these cases, the application of the EMA is often comparable to halving the dipole size in the original DDA, thus reducing the simulation time by about an order of magnitude for the same accuracy. For a coated BC model based on transmission electron microscope observations, the EMA (specifically, the Maxwell Garnett variant) significantly improves the accuracy when the dipole size is larger than ¼ of the monomer diameter. For instance, the relative error of extinction efficiency is reduced from 4.7% to 0.3% when the dipole size equals that of the spherical monomer. Moreover, the EMA-DDA achieves the accuracy of 1% for extinction, absorption, and scattering efficiencies using three times larger dipoles than that with the original DDA, corresponding to about 30 times faster simulations.
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Forello AC, Cunha-Lopes I, Almeida SM, Alves CA, Tchepel O, Crova F, Vecchi R. Insights on the combination of off-line and on-line measurement approaches for source apportionment studies. THE SCIENCE OF THE TOTAL ENVIRONMENT 2023; 900:165860. [PMID: 37516189 DOI: 10.1016/j.scitotenv.2023.165860] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/07/2023] [Revised: 06/28/2023] [Accepted: 07/26/2023] [Indexed: 07/31/2023]
Abstract
This paper presents a source apportionment study performed on a dataset collected at a trafficked site in Coimbra (Portugal) during the period December 2018-June 2019. The novelty of this work consists in the methodological approach used and the sensitivity study carried out to give hints to potential future applications. Indeed, a multi-time resolution and multi-parameter study was performed joining together aerosol data from 24-h chemically characterized samples and high-time resolution multi-wavelength absorption coefficients retrieved by an Aethalometer. A detailed sensitivity study on the most suitable combination of time resolution and uncertainties was carried out to obtain reliable physical and stable solutions over all analyses. In parallel, a regular EPA-PMF source apportionment study using chemical and optical variables averaged on 24 h is presented and discussed in comparison to the more complex multi-time and multi-parameter approach. Apart from results pertaining to the identification and relevance of different sources in Coimbra, the methodological results shown here can give guidance for readers who want to implement optical variables jointly with chemical ones in the same model run.
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Affiliation(s)
- Alice C Forello
- Department of Physics, Università degli Studi di Milano, Milan 20133, Italy; National Institute of Nuclear Physics INFN-Milan, Milan 20133, Italy
| | - Inés Cunha-Lopes
- Centro de Ciências e Tecnologias Nucleares, Instituto Superior Técnico, Universidade de Lisboa, 2695-066 Bobadela-LRS, Portugal
| | - Susana M Almeida
- Centro de Ciências e Tecnologias Nucleares, Instituto Superior Técnico, Universidade de Lisboa, 2695-066 Bobadela-LRS, Portugal
| | - Célia A Alves
- Centre of Environmental and Marine Studies, Department of Environment, University of Aveiro, 3810-193 Aveiro, Portugal
| | - Oxana Tchepel
- CITTA, Faculty of Sciences and Technology, University of Coimbra, 3004-531 Coimbra, Portugal
| | - Federica Crova
- Department of Physics, Università degli Studi di Milano, Milan 20133, Italy; National Institute of Nuclear Physics INFN-Milan, Milan 20133, Italy
| | - Roberta Vecchi
- Department of Physics, Università degli Studi di Milano, Milan 20133, Italy; National Institute of Nuclear Physics INFN-Milan, Milan 20133, Italy.
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Chen D, Zhao W, Zhang L, Zhao Q, Zhang J, Chen F, Li H, Guan M, Zhao Y. Characterization and source apportionment for light absorption amplification of black carbon at an urban site in eastern China. THE SCIENCE OF THE TOTAL ENVIRONMENT 2023; 865:161180. [PMID: 36581288 DOI: 10.1016/j.scitotenv.2022.161180] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/24/2022] [Revised: 12/06/2022] [Accepted: 12/21/2022] [Indexed: 06/17/2023]
Abstract
The mass absorption efficiency (MAE) of black carbon (BC) could be amplified by both internal mixing and the lensing effect from non-absorbing coating, which could intensify the global warming effect of BC. In this study, a two-year-long continuous campaign with measurements of aerosol optical properties and chemical composition were conducted in Nanjing, a typical polluted city in the Yangtze River Delta (YRD) region. Relatively large MAE values were observed in 2016, and the high BC internal mixing level could be the main cause. The strong positive correlation between the ratio of non-absorbing particulate matter (NAPM) over elemental carbon (EC) and the MAE value indicated that the coating thickness of BC largely promotes its light absorption ability. The impacts of chemical component coating on MAE amplification in autumn and winter were greater than in other seasons. Multiple linear regression was performed to estimate the MAE amplification effect by internal mixing and the coating of different chemical components. Nitrate coating had the strongest impact on MAE amplification, followed by organic matter. The effects of organic matter and nitrate coatings on MAE amplification increased with the internal mixing index (IMI). Based on the positive matrix factorization (PMF) model, it was found that large decrease in the contribution of industrial emissions and coal combustion to PM2.5 from 2016 to 2017 was the main cause for MAE reduction. The novel statistical model developed in this study could be a useful tool to separate the impacts of internal mixing and non-absorbing coating.
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Affiliation(s)
- Dong Chen
- Jiangsu Provincial Academy of Environmental Science, 176 North Jiangdong Rd., Nanjing, Jiangsu 210036, China; State Key Laboratory of Pollution Control and Resource Reuse, and School of the Environment, Nanjing University, 163 Xianlin Ave., Nanjing, Jiangsu 210023, China
| | - Wenxin Zhao
- State Key Laboratory of Pollution Control and Resource Reuse, and School of the Environment, Nanjing University, 163 Xianlin Ave., Nanjing, Jiangsu 210023, China
| | - Lei Zhang
- State Key Laboratory of Pollution Control and Resource Reuse, and School of the Environment, Nanjing University, 163 Xianlin Ave., Nanjing, Jiangsu 210023, China; Jiangsu Collaborative Innovation Center of Atmospheric Environment and Equipment Technology (CICAEET), Nanjing University of Information Science and Technology, Nanjing, Jiangsu 210044, China.
| | - Qiuyue Zhao
- Jiangsu Provincial Academy of Environmental Science, 176 North Jiangdong Rd., Nanjing, Jiangsu 210036, China.
| | - Jie Zhang
- Jiangsu Environmental Engineering and Technology Co., Ltd., Jiangsu Environmental Protection Group Co., Ltd., 8 East Jialingjiang St., Nanjing, Jiangsu 210019, China
| | - Feng Chen
- Jiangsu Environmental Engineering and Technology Co., Ltd., Jiangsu Environmental Protection Group Co., Ltd., 8 East Jialingjiang St., Nanjing, Jiangsu 210019, China
| | - Huipeng Li
- Jiangsu Provincial Academy of Environmental Science, 176 North Jiangdong Rd., Nanjing, Jiangsu 210036, China
| | - Miao Guan
- Jiangsu Key Laboratory for Biodiversity and Biotechnology, College of Life Sciences, Nanjing Normal University, 1 Wenyuan Rd., Nanjing, Jiangsu 210023, China
| | - Yu Zhao
- State Key Laboratory of Pollution Control and Resource Reuse, and School of the Environment, Nanjing University, 163 Xianlin Ave., Nanjing, Jiangsu 210023, China; Jiangsu Collaborative Innovation Center of Atmospheric Environment and Equipment Technology (CICAEET), Nanjing University of Information Science and Technology, Nanjing, Jiangsu 210044, China
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Singh PK, Adhikary B, Chen X, Kang S, Poudel SP, Tashi T, Goswami A, Puppala SP. Variability of ambient black carbon concentration in the Central Himalaya and its assessment over the Hindu Kush Himalayan region. THE SCIENCE OF THE TOTAL ENVIRONMENT 2023; 858:160137. [PMID: 36375556 DOI: 10.1016/j.scitotenv.2022.160137] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/11/2022] [Revised: 11/07/2022] [Accepted: 11/08/2022] [Indexed: 06/16/2023]
Abstract
During 2015-2018, eight black carbon (BC) monitoring sites were established in Nepal and Bhutan to fill a significant data gap regarding BC measurement in Central Himalaya. This manuscript analyzes and presents data from these eight stations and one additional station on the Tibetan plateau (TP). Complex topography, varied emission sources, and atmospheric transport pathways significantly impacted the BC concentrations across these stations, with annual mean concentrations varying from 36 ng m-3 to 45,737 ng m-3. Higher annual mean concentrations (5609 ± 4515 ng m-3) were recorded at low-altitude sites than in other locations, with seasonal concentrations highest in the winter (7316 ± 2541 ng m-3). In contrast, the annual mean concentrations were lowest at high-altitude sites (376 ± 448 ng m-3); the BC concentrations at these sites peaked during the pre-monsoon season (930 ± 685 ng m-3). Potential source contributions to the total observed BC were analyzed using the absorption angstrom exponent (AAE). AAE analysis showed the dominance of biomass burning sources (>50 %), except in Kathmandu. By combining our data with previously published literature, we put our measurements in perspective by presenting a comprehensive assessment of BC concentrations and their variability over the Hindu Kush Himalayan (HKH) region. The BC levels in all three geographic regions, high, mid, and low altitude significantly influenced by the persistent seasonal meteorology. However, the mid-altitude stations were substantially affected by valley dynamics and urbanization. The low-altitude stations experienced high BC concentrations during the winter and post-monsoon seasons. Concentration weighted trajectory (CWT) and frequency analyses revealed the dominance of long-range transported pollution during winter over HKH, from west to east. South Asian sources remained significant during the monsoon season. During pre- and post-monsoon, the local, regional, and long-distance pollution varied depending on the location of the receptor site.
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Affiliation(s)
- Praveen Kumar Singh
- International Centre for Integrated Mountain Development (ICIMOD), G.P.O. Box 3226, Kathmandu, Nepal; Centre of Excellence in Disaster Mitigation and Management, Indian Institute of Technology Roorkee, Roorkee, Uttarakhand 247667, India
| | - Bhupesh Adhikary
- International Centre for Integrated Mountain Development (ICIMOD), G.P.O. Box 3226, Kathmandu, Nepal
| | - Xintong Chen
- State Key Laboratory of Cryospheric Science, Northwest Institute of Eco-Environment and Resources, Chinese Academy of Sciences, Lanzhou 730000, China; University of Chinese Academy of Sciences, Beijing 100049, China
| | - Shichang Kang
- State Key Laboratory of Cryospheric Science, Northwest Institute of Eco-Environment and Resources, Chinese Academy of Sciences, Lanzhou 730000, China; University of Chinese Academy of Sciences, Beijing 100049, China
| | - Shankar Prasad Poudel
- Department of Environment, Ministry of Forests and Environment, Forest-Complex, Babarmahal, Kathmandu, Nepal
| | - Tshering Tashi
- National Environment Commission, Royal Government of Bhutan, Tashi-Chhodzong Lam, Thimphu, Bhutan
| | - Ajanta Goswami
- Centre of Excellence in Disaster Mitigation and Management, Indian Institute of Technology Roorkee, Roorkee, Uttarakhand 247667, India; Department of Earth Sciences, Indian Institute of Technology Roorkee, Roorkee, Uttarakhand 247667, India
| | - Siva Praveen Puppala
- International Centre for Integrated Mountain Development (ICIMOD), G.P.O. Box 3226, Kathmandu, Nepal.
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Santiago-De La Rosa N, Mugica-Álvarez V, González-Cardoso G, De Vizcaya-Ruiz A, Uribe-Ramírez M, Valle-Hernández BL. Emission Factors of Polycyclic Aromatic Hydrocarbons and Oxidative Potential of Fine Particles Emitted from Crop Residues Burning. Polycycl Aromat Compd 2022. [DOI: 10.1080/10406638.2021.1924801] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
Affiliation(s)
- Naxieli Santiago-De La Rosa
- Universidad Autónoma Metropolitana, Ciudad de México, Mexico
- Centro de Ciencias de la Atmósfera, Universidad Nacional Autónoma de México, Ciudad de México, Mexico
| | | | | | - Andrea De Vizcaya-Ruiz
- Departamento de Toxicología, Centro de Investigación y de Estudios Avanzados del Instituto Politécnico Nacional. Av. Instituto Politécnico Nacional, CDMX, Mexico
| | - Marisela Uribe-Ramírez
- Departamento de Toxicología, Centro de Investigación y de Estudios Avanzados del Instituto Politécnico Nacional. Av. Instituto Politécnico Nacional, CDMX, Mexico
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Vogel F, Lacher L, Nadolny J, Saathoff H, Leisner T, Möhler O. Development and validation of a new cloud simulation experiment for lab-based aerosol-cloud studies. THE REVIEW OF SCIENTIFIC INSTRUMENTS 2022; 93:095106. [PMID: 36182527 DOI: 10.1063/5.0098777] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/12/2022] [Accepted: 08/26/2022] [Indexed: 06/16/2023]
Abstract
The Aerosol Interaction and Dynamics in the Atmosphere (AIDA) cloud expansion chamber with a volume of 84 m3 was extended for the small cloud expansion chamber AIDA mini (AIDAm) with a volume of 20 L. AIDAm is located in the cold room of AIDA and can perform automated ice-nucleation measurements over longer time periods of hours to days. AIDAm samples from the AIDA chamber, which acts as a reservoir of atmospheric aerosol types, which can slowly be modified by physical or chemical processes similar to those occurring in the atmosphere. AIDAm was validated for accurate ice-nucleation temperature control by measuring homogeneous freezing of pure water droplets at temperatures around -34 °C and for immersion freezing induced by dust aerosol particles in the temperature range between -20 and -30 °C. Further validation experiments at cirrus cloud temperatures of -45 °C revealed that AIDAm can distinguish between heterogeneous ice formation on mineral dust aerosols and homogeneous freezing of sulfuric acid solution particles. The contribution of homogeneous and heterogeneous ice formation processes to the ice-nucleation activity of coated dust particles was investigated in a 7 h long experiment, where solid dust particles were slowly coated with sulfuric acid. The continuous AIDAm measurements with a time resolution of 6 min showed a substantial suppression of the heterogeneous freezing phenomenon and an increasing role of homogeneous freezing while the coating amount was slowly increased. This experiment proved the capability of AIDAm to sensitively detect small changes in the ice-nucleation ability of aerosols, which undergo slow processing like chemical surface coating.
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Affiliation(s)
- F Vogel
- Institute of Meteorology and Climate Research, Karlsruhe Institute of Technology, Hermann-von-Helmholtz-Platz 1, 76344 Eggenstein-Leopoldshafen, Germany
| | - L Lacher
- Institute of Meteorology and Climate Research, Karlsruhe Institute of Technology, Hermann-von-Helmholtz-Platz 1, 76344 Eggenstein-Leopoldshafen, Germany
| | - J Nadolny
- Institute of Meteorology and Climate Research, Karlsruhe Institute of Technology, Hermann-von-Helmholtz-Platz 1, 76344 Eggenstein-Leopoldshafen, Germany
| | - H Saathoff
- Institute of Meteorology and Climate Research, Karlsruhe Institute of Technology, Hermann-von-Helmholtz-Platz 1, 76344 Eggenstein-Leopoldshafen, Germany
| | - T Leisner
- Institute of Meteorology and Climate Research, Karlsruhe Institute of Technology, Hermann-von-Helmholtz-Platz 1, 76344 Eggenstein-Leopoldshafen, Germany
| | - O Möhler
- Institute of Meteorology and Climate Research, Karlsruhe Institute of Technology, Hermann-von-Helmholtz-Platz 1, 76344 Eggenstein-Leopoldshafen, Germany
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Zhang F, Peng J, Chen L, Collins D, Li Y, Jiang S, Liu J, Zhang R. The effect of black carbon aging from NO 2 oxidation of SO 2 on its morphology, optical and hygroscopic properties. ENVIRONMENTAL RESEARCH 2022; 212:113238. [PMID: 35395235 DOI: 10.1016/j.envres.2022.113238] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/11/2021] [Revised: 02/25/2022] [Accepted: 03/31/2022] [Indexed: 06/14/2023]
Abstract
Atmospheric aging of black carbon (BC) leads to changes in its physiochemical properties, exerting complex effects on environment and climate. In this study, we have conducted laboratory chamber experiments to investigate the effects of BC aging on its morphology, hygroscopicity and optical properties by exposing monodisperse fresh BC particles to ambient ubiquitous species of nitrogen dioxide (NO2), sulfur dioxide (SO2) and ammonia (NH3) in absence of UV light. We show a rapid aging from highly fractal to compacted aggregates for the monodisperse BC particles with an initial diameter of 150 nm, with decline in the dynamic shape factor (χ) from about 1.8 to nearly 1. The effective density of the monodisperse BC particles increases from ∼0.54 to 1.50 g cm-3 accordingly. The aging process leads to that the light scattering, absorption, and single scattering albedo of the monodisperse BC particles are strongly enhanced by factors of 7.0, 1.8 and 3.0 respectively. By comparing with the BC aging from other mechanisms, we reveal a critical role of the composition of the coating materials on BC in determining its light absorption enhancement. Moreover, due to strong water uptake capacity of the aged BC particles, the light absorption enhancement (Eabs) could be 40-60% higher at humid atmosphere compared with dry conditions. This BC aging process from NO2 oxidation of SO2 may occur commonly in polluted regions and thus considerably alter its effects on regional air quality and climate.
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Affiliation(s)
- Fang Zhang
- School of Civil and Environmental Engineering, Harbin Institute of Technology (Shenzhen), 518055, Shenzhen, China
| | - Jianfei Peng
- Departments of Atmospheric Sciences and Chemistry, Texas A&M University, College Station, TX, USA; Tianjin Key Laboratory of Urban Transport Emission Research, College of Environmental Science and Engineering, Nankai University, Tianjin, 300071, China
| | - Lu Chen
- College of Global Change and Earth System Science, Beijing Normal University, Beijing, 100875, China
| | - Don Collins
- Chemical and Environmental Engineering, University of California, Riverside, CA, 92521, USA
| | - Yixin Li
- Departments of Atmospheric Sciences and Chemistry, Texas A&M University, College Station, TX, USA
| | - Sihui Jiang
- College of Global Change and Earth System Science, Beijing Normal University, Beijing, 100875, China
| | - Jieyao Liu
- College of Global Change and Earth System Science, Beijing Normal University, Beijing, 100875, China
| | - Renyi Zhang
- Departments of Atmospheric Sciences and Chemistry, Texas A&M University, College Station, TX, USA.
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Pani SK, Lin NH, Lee CT, Griffith SM, Chang JHW, Hsu BJ. Insights into aerosol chemical composition and optical properties at Lulin Atmospheric Background Station (2862 m asl) during two contrasting seasons. THE SCIENCE OF THE TOTAL ENVIRONMENT 2022; 834:155291. [PMID: 35439502 DOI: 10.1016/j.scitotenv.2022.155291] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/17/2022] [Revised: 04/06/2022] [Accepted: 04/11/2022] [Indexed: 06/14/2023]
Abstract
Continental outflows from peninsular Southeast Asia and East Asia dominate the widespread dispersal of air pollutants over subtropical western North Pacific during spring and autumn, respectively. This study analyses the chemical composition and optical properties of PM10 aerosols during autumn and spring at a representative high-altitude site, viz., Lulin Atmospheric Background Station (23.47°N, 120.87°E; 2862 m a.s.l.), Taiwan. PM10 mass was reconstructed and the contributions of major chemical components were also delineated. Aerosol scattering (σsp) and absorption (σap) coefficients were regressed on mass densities of major chemical components by assuming external mixing between them, and the site-specific mass scattering efficiency (MSE) and mass absorption efficiency (MAE) of individual components for dry conditions were determined. NH4NO3 exhibited the highest MSE among all components during both seasons (8.40 and 12.58 m2 g-1 at 550 nm in autumn and spring, respectively). (NH4)2SO4 and organic matter (OM) accounted for the highest σsp during autumn (51%) and spring (50%), respectively. Mean MAE (mean contribution to σap) of elemental carbon (EC) at 550 nm was 2.51 m2 g-1 (36%) and 7.30 m2 g-1 (61%) in autumn and spring, respectively. Likewise, the mean MAE (mean contribution to σap) of organic carbon (OC) at 550 nm was 0.84 m2 g-1 (64%) and 0.83 m2 g-1 (39%) in autumn and spring, respectively. However, a classification matrix, based on scattering Ångström exponent, absorption Ångström exponent, and single scattering albedo (ω), demonstrated that the composite absorbing aerosols were EC-dominated (with weak absorption; ω = 0.91-0.95) in autumn and a combination of EC-dominated and EC/OC mixture (with moderate absorption; ω = 0.85-0.92) in spring. This study demonstrates a strong link between chemical composition and optical properties of aerosol and provides essential information for model simulations to assess the imbalance in regional radiation budget with better accuracy over the western North Pacific.
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Affiliation(s)
- Shantanu Kumar Pani
- Department of Atmospheric Sciences, National Central University, Taoyuan 32001, Taiwan.
| | - Neng-Huei Lin
- Department of Atmospheric Sciences, National Central University, Taoyuan 32001, Taiwan; Center for Environmental Monitoring and Technology, National Central University, Taoyuan 32001, Taiwan
| | - Chung-Te Lee
- Graduate Institute of Environmental Engineering, National Central University, Taoyuan 32001, Taiwan.
| | - Stephen M Griffith
- Department of Atmospheric Sciences, National Central University, Taoyuan 32001, Taiwan
| | - Jackson Hian-Wui Chang
- Department of Atmospheric Sciences, National Central University, Taoyuan 32001, Taiwan; Preparatory Center for Science and Technology, University Malaysia Sabah, Kota Kinabalu 88400, Malaysia
| | - Bo-Jun Hsu
- Graduate Institute of Environmental Engineering, National Central University, Taoyuan 32001, Taiwan
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10
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Liu X, Zheng M, Liu Y, Jin Y, Liu J, Zhang B, Yang X, Wu Y, Zhang T, Xiang Y, Liu B, Yan C. Intercomparison of equivalent black carbon (eBC) and elemental carbon (EC) concentrations with three-year continuous measurement in Beijing, China. ENVIRONMENTAL RESEARCH 2022; 209:112791. [PMID: 35101394 DOI: 10.1016/j.envres.2022.112791] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/24/2021] [Revised: 12/31/2021] [Accepted: 01/20/2022] [Indexed: 06/14/2023]
Abstract
Due to the lack of black carbon (BC) measurement data in some cases, elemental carbon (EC) is often used as a surrogate of BC, with a simple assumption that they are interchangeable. Such assumption will inevitably lead to uncertainties in radiative forcing estimation and health impact assessment. In order to quantitatively and systematically evaluate the relationship between BC and EC as well as factors responsible for their difference, 3-year collocated equivalent BC (eBC) and EC measurements with 1-h resolution were performed in Beijing, China continuously from 2016 to 2019. EBC concentration was measured by the multi-wavelength aethalometer (AE-33) based on optical analysis, while EC concentration was determined by semi-continuous OC/EC analyzer with thermal-optical method. The results showed that around 90% of eBC concentration was higher than that of EC, with average difference between eBC and EC as 1.21 μg m-3 (accounting for 33% of average eBC in Beijing). EBC and EC concentrations exhibited strong correlation (r = 0.90) during the whole study period, but the slopes (or eBC/EC ratio) and correlation coefficients varied across seasons (spring: 1.67 and 0.94; summer: 0.91 and 0.65; fall: 1.15 and 0.88; winter: 1.09 and 0.91, respectively). Based on the information from shell/core ratios by Single Particle Soot Photometer (SP2), source apportionment results by positive matrix factorization model, and chemical composition of PM2.5, the differences between eBC and EC concentrations were found to be primarily related to BC aging process and secondary components as evidenced by strong positive correlation with secondary species (e.g., secondary organic carbon and nitrate). This study provided seasonal specific conversion factors of eBC and EC in Beijing and helpful reference for other areas, which will contribute new knowledge of carbonaceous aerosol and reduce uncertainty in assessing future climate change and health studies of BC.
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Affiliation(s)
- Xiaomeng Liu
- State Key Joint Laboratory of Environmental Simulation and Pollution Control, College of Environmental Sciences and Engineering, Peking University, Beijing, 100871, China
| | - Mei Zheng
- State Key Joint Laboratory of Environmental Simulation and Pollution Control, College of Environmental Sciences and Engineering, Peking University, Beijing, 100871, China.
| | - Yue Liu
- State Key Joint Laboratory of Environmental Simulation and Pollution Control, College of Environmental Sciences and Engineering, Peking University, Beijing, 100871, China
| | - Yali Jin
- State Key Joint Laboratory of Environmental Simulation and Pollution Control, College of Environmental Sciences and Engineering, Peking University, Beijing, 100871, China
| | - Junyi Liu
- State Key Joint Laboratory of Environmental Simulation and Pollution Control, College of Environmental Sciences and Engineering, Peking University, Beijing, 100871, China
| | - Boya Zhang
- State Key Joint Laboratory of Environmental Simulation and Pollution Control, College of Environmental Sciences and Engineering, Peking University, Beijing, 100871, China
| | - Xi Yang
- State Key Joint Laboratory of Environmental Simulation and Pollution Control, College of Environmental Sciences and Engineering, Peking University, Beijing, 100871, China
| | - Yazhen Wu
- State Key Joint Laboratory of Environmental Simulation and Pollution Control, College of Environmental Sciences and Engineering, Peking University, Beijing, 100871, China
| | - Tianle Zhang
- State Key Joint Laboratory of Environmental Simulation and Pollution Control, College of Environmental Sciences and Engineering, Peking University, Beijing, 100871, China
| | - Yaxin Xiang
- State Key Joint Laboratory of Environmental Simulation and Pollution Control, College of Environmental Sciences and Engineering, Peking University, Beijing, 100871, China
| | - Baoxian Liu
- Beijing Key Laboratory of Airborne Particulate Matter Monitoring Technology, Beijing Municipal Environmental Monitoring Center, Beijing, 100048, China
| | - Caiqing Yan
- Environment Research Institute, Shandong University, Qingdao, 266237, China.
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11
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Zhai J, Yang X, Li L, Bai B, Liu P, Huang Y, Fu TM, Zhu L, Zeng Z, Tao S, Lu X, Ye X, Wang X, Wang L, Chen J. Absorption Enhancement of Black Carbon Aerosols Constrained by Mixing-State Heterogeneity. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2022; 56:1586-1593. [PMID: 35038862 DOI: 10.1021/acs.est.1c06180] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
Abstract
Atmospheric black carbon (BC) has a large yet highly uncertain contribution to global warming. When mixed with non-BC/coating material during atmospheric aging, the BC light absorption can be enhanced through the lensing effect. Laboratory and modeling studies have consistently found strong BC absorption enhancement, while the results in ambient measurements are conflicting, with some reporting weak absorption enhancement even for particles with large bulk coating amounts. Here, from our direct field observations, we report both large and minor absorption enhancement factors for different BC-containing particle populations with large bulk non-BC-to-BC mass ratios. By gaining insights into the measured coating material distribution across each particle population, we find that the level of absorption enhancement is strongly dependent on the particle-resolved mixing state. Our study shows that the greater mixing-state heterogeneity results in the larger difference between observed and predicted absorption enhancement. We demonstrate that by considering the variability in coating material thickness in the optical model, the previously observed model measurement discrepancy of absorption enhancement can be reconciled. The observations and improved optical models reported here highlight the importance of mixing-state heterogeneity on BC's radiative forcing, which should be better resolved in large-scale models to increase confidence when estimating the aerosol radiation effect.
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Affiliation(s)
- Jinghao Zhai
- School of Environmental Science and Engineering, Southern University of Science and Technology, Shenzhen 518055, China
| | - Xin Yang
- School of Environmental Science and Engineering, Southern University of Science and Technology, Shenzhen 518055, China
| | - Ling Li
- Shanghai Key Laboratory of Atmospheric Particle Pollution and Prevention, Department of Environmental Science and Engineering, Fudan University, Shanghai 200433, China
| | - Bin Bai
- School of Earth and Atmospheric Sciences, Georgia Institute of Technology, Atlanta, Georgia 30332, United States
| | - Pengfei Liu
- School of Earth and Atmospheric Sciences, Georgia Institute of Technology, Atlanta, Georgia 30332, United States
| | - Yuanlong Huang
- Division of Geological and Planetary Sciences, California Institute of Technology, Pasadena, California 91125, United States
| | - Tzung-May Fu
- School of Environmental Science and Engineering, Southern University of Science and Technology, Shenzhen 518055, China
| | - Lei Zhu
- School of Environmental Science and Engineering, Southern University of Science and Technology, Shenzhen 518055, China
| | - Zhenzhong Zeng
- School of Environmental Science and Engineering, Southern University of Science and Technology, Shenzhen 518055, China
| | - Shu Tao
- School of Environmental Science and Engineering, Southern University of Science and Technology, Shenzhen 518055, China
- Laboratory for Earth Surface Process, College of Urban and Environmental Sciences, Peking University, Beijing 100871, China
| | - Xiaohui Lu
- Shanghai Key Laboratory of Atmospheric Particle Pollution and Prevention, Department of Environmental Science and Engineering, Fudan University, Shanghai 200433, China
| | - Xingnan Ye
- Shanghai Key Laboratory of Atmospheric Particle Pollution and Prevention, Department of Environmental Science and Engineering, Fudan University, Shanghai 200433, China
| | - Xiaofei Wang
- Shanghai Key Laboratory of Atmospheric Particle Pollution and Prevention, Department of Environmental Science and Engineering, Fudan University, Shanghai 200433, China
| | - Lin Wang
- Shanghai Key Laboratory of Atmospheric Particle Pollution and Prevention, Department of Environmental Science and Engineering, Fudan University, Shanghai 200433, China
| | - Jianmin Chen
- Shanghai Key Laboratory of Atmospheric Particle Pollution and Prevention, Department of Environmental Science and Engineering, Fudan University, Shanghai 200433, China
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12
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Zhou Q, Cheng C, Yang S, Yuan M, Meng J, Gong H, Zhong Q, Zhang Y, Xie Y, Zhou Z, Li M. Enhanced mixing state of black carbon with nitrate in single particles during haze periods in Zhengzhou, China. J Environ Sci (China) 2022; 111:185-196. [PMID: 34949348 DOI: 10.1016/j.jes.2021.03.031] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2020] [Revised: 03/10/2021] [Accepted: 03/12/2021] [Indexed: 06/14/2023]
Abstract
Black carbon (BC) plays an important role in air quality and climate change, which is closely associated with its mixing state and chemical compositions. In this work the mixing state of BC-containing single particles was investigated to explore the evolution process of ambient BC particles using a single particle aerosol mass spectrometer (SPAMS) in March 2018 in Zhengzhou, China. The BC-containing particles accounted for 61.4% of total detected ambient single particles and were classified into five types including BC-nitrate (BC-N, 52.3%) as the most abundant species, followed by BC-nitrate-sulfate (BC-NS, 22.4%), BCOC (16.8%), BC-fresh (BC-F, 4.5%) and BC-sulfate particles (BC-S, 4.0%). With enhancement of the ambient nitrate concentration, the relative peak area (RPA) of nitrate in BC-N and BCNS particles both increased, yet only the number fraction (Nf) of BCN particles increased while the Nf of BC-NS particles decreased, suggesting that the enhanced mixing state of BC with nitrate was mainly due to the increase in the ambient nitrate mass concentration. In addition, the Nf of BC-N decreased from 65.3% to 28.4% as the absorbing Ångström exponents (AAE) of eBC increased from 0.75 to 1.45, which indicated the reduction of light absorption ability of aged BC particles with the enhanced formation of BC-N particles. The results of this work indicated a change in the mixing state of BC particles due to the dominance of nitrate in PM2.5, which also influenced the optical properties of aged BC particles.
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Affiliation(s)
- Qianni Zhou
- Institute of Mass Spectrometry and Atmospheric Environment, Guangdong Provincial Engineering Research Center for On-line Source Apportionment System of Air Pollution, Jinan University, Guangzhou 510632, China; Guangdong-Hongkong-Macau Joint Laboratory of Collaborative Innovation for Environmental Quality, Guangzhou 510632, China
| | - Chunlei Cheng
- Institute of Mass Spectrometry and Atmospheric Environment, Guangdong Provincial Engineering Research Center for On-line Source Apportionment System of Air Pollution, Jinan University, Guangzhou 510632, China; Guangdong-Hongkong-Macau Joint Laboratory of Collaborative Innovation for Environmental Quality, Guangzhou 510632, China; School of Environment and Planning, Liaocheng University, Liaocheng 252000, China.
| | - Suxia Yang
- Institute of Mass Spectrometry and Atmospheric Environment, Guangdong Provincial Engineering Research Center for On-line Source Apportionment System of Air Pollution, Jinan University, Guangzhou 510632, China; Institute for Environment and Climate Research, Jinan University, Guangzhou 510632, China
| | - Minghao Yuan
- Zhengzhou Environmental Protection Monitoring Center Station, Zhengzhou 450007, China
| | - Jingjing Meng
- School of Environment and Planning, Liaocheng University, Liaocheng 252000, China
| | - Haifeng Gong
- Institute of Mass Spectrometry and Atmospheric Environment, Guangdong Provincial Engineering Research Center for On-line Source Apportionment System of Air Pollution, Jinan University, Guangzhou 510632, China; Guangdong-Hongkong-Macau Joint Laboratory of Collaborative Innovation for Environmental Quality, Guangzhou 510632, China
| | - Qien Zhong
- Institute of Mass Spectrometry and Atmospheric Environment, Guangdong Provincial Engineering Research Center for On-line Source Apportionment System of Air Pollution, Jinan University, Guangzhou 510632, China; Guangdong-Hongkong-Macau Joint Laboratory of Collaborative Innovation for Environmental Quality, Guangzhou 510632, China
| | - Yao Zhang
- Institute of Mass Spectrometry and Atmospheric Environment, Guangdong Provincial Engineering Research Center for On-line Source Apportionment System of Air Pollution, Jinan University, Guangzhou 510632, China; Guangdong-Hongkong-Macau Joint Laboratory of Collaborative Innovation for Environmental Quality, Guangzhou 510632, China
| | - Yutong Xie
- Institute of Mass Spectrometry and Atmospheric Environment, Guangdong Provincial Engineering Research Center for On-line Source Apportionment System of Air Pollution, Jinan University, Guangzhou 510632, China; Guangdong-Hongkong-Macau Joint Laboratory of Collaborative Innovation for Environmental Quality, Guangzhou 510632, China
| | - Zhen Zhou
- Institute of Mass Spectrometry and Atmospheric Environment, Guangdong Provincial Engineering Research Center for On-line Source Apportionment System of Air Pollution, Jinan University, Guangzhou 510632, China; Guangdong-Hongkong-Macau Joint Laboratory of Collaborative Innovation for Environmental Quality, Guangzhou 510632, China
| | - Mei Li
- Institute of Mass Spectrometry and Atmospheric Environment, Guangdong Provincial Engineering Research Center for On-line Source Apportionment System of Air Pollution, Jinan University, Guangzhou 510632, China; Guangdong-Hongkong-Macau Joint Laboratory of Collaborative Innovation for Environmental Quality, Guangzhou 510632, China.
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13
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Suitability of Different Methods for Measuring Black Carbon Emissions from Marine Engines. ATMOSPHERE 2021. [DOI: 10.3390/atmos13010031] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Black carbon (BC) emissions intensify global warming and are linked to adverse health effects. The International Maritime Organization (IMO) considers the impact of BC emissions from international shipping. A prerequisite for the anticipated limits to BC emissions from marine engines is a reliable measurement method. The three candidate methods (photoacoustic spectroscopy (PAS), laser-induced incandescence (LII), and filter smoke number (FSN)) selected by the IMO were evaluated with extensive ship exhaust matrices obtained by different fuels, engines, and emission control devices. A few instruments targeted for atmospheric measurements were included as well. The BC concentrations were close to each other with the smoke meters (AVL 415S and 415SE), PAS (AVL MSS), LII (Artium-300), MAAP 5012, aethalometers (Magee AE-33 and AE-42), and EC (TOA). In most cases, the standard deviation between instruments was in the range of 5–15% at BC concentrations below 30 mg Sm−3. Some differences in the BC concentrations measured with these instruments were potentially related to the ratio of light-absorbing compounds to sulphates or to particle sizes and morphologies. In addition, calibrations, sampling, and correction of thermophoretic loss of BC explained differences in the BC results. However, overall differences in the BC results obtained with three candidate methods selected by the IMO were low despite challenging exhaust compositions from marine diesel engines. Findings will inform decision making on BC emission control from marine engines.
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14
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Mbengue S, Zikova N, Schwarz J, Vodička P, Šmejkalová AH, Holoubek I. Mass absorption cross-section and absorption enhancement from long term black and elemental carbon measurements: A rural background station in Central Europe. THE SCIENCE OF THE TOTAL ENVIRONMENT 2021; 794:148365. [PMID: 34198082 PMCID: PMC8434419 DOI: 10.1016/j.scitotenv.2021.148365] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 03/24/2021] [Revised: 05/24/2021] [Accepted: 06/06/2021] [Indexed: 06/13/2023]
Abstract
Black carbon (BC) is a dominant aerosol light absorber, and its brown carbon (BrC) coating can enhance absorption and lead to uncertainties concerning the radiative forcing estimation. This study investigates the mass absorption cross-section of equivalent BC (MACeBC) during a long-term field measurement (2013-2017) at a rural Central European site. The MAC enhancement factor (Eabs) and the contribution of BrC coatings to the absorption coefficient (Babs) were estimated by combining different approaches. The annual mean Babs and MACeBC values decreased slightly over the measurement period associated with change in the submicron aerosol size distribution. Regardless of the wavelength, Babs exhibited clear seasonal and diurnal variations, with higher values in winter when a higher absorption Ångström exponent (1.4) was observed due to the local biomass burning (BB). In contrast, MACeBC did not have a distinct temporal trend at 600 nm (7.84 ± 2.79 m2 g-1), while it showed a seasonal trend at 370 nm with higher values in winter (15.64 ± 4.77 m2 g-1). During this season, Eabs_660 was 1.18 ± 0.27 and did not exhibit any clear wavelength dependence, despite the influence of BB. During the study period, BrC-attributed absorption was observed in 31% of the samples, with a contribution of up to 40% of total Babs. In summer, the Eabs_660 increased to 1.59 ± 0.60, when a larger BC coating could be formed by secondary aerosol fractions. During this season, MACeBC_660 and Eabs_660 showed comparable source profiles that were mainly associated with aged air masses over central Europe, thereby supporting the fact that characteristics of coating materials formed during atmospheric aging are a major factor driving the MACeBC_660 measured at the regional background site. Further field investigations of the composition of BC coatings would help to better understand and estimate uncertainties related to the radiative effect of aerosols.
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Affiliation(s)
- Saliou Mbengue
- Global Change Research Institute of the CAS, Brno 603 00, Czech Republic.
| | - Nadezda Zikova
- Institute of Chemical Process Fundamentals of the CAS, Prague 180 00, Czech Republic
| | - Jaroslav Schwarz
- Institute of Chemical Process Fundamentals of the CAS, Prague 180 00, Czech Republic
| | - Petr Vodička
- Institute of Chemical Process Fundamentals of the CAS, Prague 180 00, Czech Republic
| | - Adéla Holubová Šmejkalová
- Czech Hydrometeorological Institute, Košetice Observatory, Košetice 394 22, Czech Republic; Institute for Environmental Studies, Faculty of Science, Charles University, Prague 128 01, Czech Republic
| | - Ivan Holoubek
- Global Change Research Institute of the CAS, Brno 603 00, Czech Republic; RECETOX, Masaryk University, Brno 625 00, Czech Republic
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15
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Lalchandani V, Kumar V, Tobler A, M Thamban N, Mishra S, Slowik JG, Bhattu D, Rai P, Satish R, Ganguly D, Tiwari S, Rastogi N, Tiwari S, Močnik G, Prévôt ASH, Tripathi SN. Real-time characterization and source apportionment of fine particulate matter in the Delhi megacity area during late winter. THE SCIENCE OF THE TOTAL ENVIRONMENT 2021; 770:145324. [PMID: 33736388 DOI: 10.1016/j.scitotenv.2021.145324] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/22/2020] [Revised: 01/15/2021] [Accepted: 01/16/2021] [Indexed: 05/21/2023]
Abstract
National Capital Region (NCR) encompassing New Delhi is one of the most polluted urban metropolitan areas in the world. Real-time chemical characterization of fine particulate matter (PM1 and PM2.5) was carried out using three aerosol mass spectrometers, two aethalometers, and one single particle soot photometer (SP2) at two sites in Delhi (urban) and one site located ~40 km downwind of Delhi, during January-March 2018. The campaign mean PM2.5 (NR-PM2.5 + BC) concentrations at the two urban sites were 153.8 ± 109.4 μg.m-3 and 127.8 ± 83.2 μg.m-3, respectively, whereas PM1 (NR-PM1 + BC) was 72.3 ± 44.0 μg.m-3 at the downwind site. PM2.5 particles were composed mostly of organics (43-44)% followed by chloride (14-17)%, ammonium (9-11)%, nitrate (9%), sulfate (8-10)%, and black carbon (11-16)%, whereas PM1 particles were composed of 47% organics, 13% sulfate as well as ammonium, 11% nitrate as well as chloride, and 5% black carbon. Organic aerosol (OA) source apportionment was done using positive matrix factorization (PMF), solved using an advanced multi-linear engine (ME-2) model. Highly mass-resolved OA mass spectra at one urban and downwind site were factorized into three primary organic aerosol (POA) factors including one traffic-related and two solid-fuel combustion (SFC), and three oxidized OA (OOA) factors. Whereas unit mass resolution OA at the other urban site was factorized into two POA factors related to traffic and SFC, and one OOA factor. OOA constituted a majority of the total OA mass (45-55)% with maximum contribution during afternoon hours ~(70-80)%. Significant differences in the absolute OOA concentration between the two urban sites indicated the influence of local emissions on the oxidized OA formation. Similar PM chemical composition, diurnal and temporal variations at the three sites suggest similar type of sources affecting the particulate pollution in Delhi and adjoining cities, but variability in mass concentration suggest more local influence than regional.
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Affiliation(s)
- Vipul Lalchandani
- Department of Civil Engineering, Indian Institute of Technology Kanpur, Kanpur, India
| | - Varun Kumar
- Laboratory of Atmospheric Chemistry, Paul Scherrer Institute, 5232 PSI Villigen, Switzerland
| | - Anna Tobler
- Laboratory of Atmospheric Chemistry, Paul Scherrer Institute, 5232 PSI Villigen, Switzerland
| | - Navaneeth M Thamban
- Department of Civil Engineering, Indian Institute of Technology Kanpur, Kanpur, India
| | - Suneeti Mishra
- Department of Civil Engineering, Indian Institute of Technology Kanpur, Kanpur, India
| | - Jay G Slowik
- Laboratory of Atmospheric Chemistry, Paul Scherrer Institute, 5232 PSI Villigen, Switzerland
| | - Deepika Bhattu
- Laboratory of Atmospheric Chemistry, Paul Scherrer Institute, 5232 PSI Villigen, Switzerland
| | - Pragati Rai
- Laboratory of Atmospheric Chemistry, Paul Scherrer Institute, 5232 PSI Villigen, Switzerland
| | - Rangu Satish
- Geosciences Division, Physical Research Laboratory, Ahmedabad, India
| | - Dilip Ganguly
- Centre for Atmospheric Sciences, Indian Institute of Technology Delhi, New Delhi, India
| | - Suresh Tiwari
- Indian Institute of Tropical Meteorology, Pune, New Delhi Branch, India
| | - Neeraj Rastogi
- Geosciences Division, Physical Research Laboratory, Ahmedabad, India
| | - Shashi Tiwari
- Department of Civil Engineering, Manav Rachna International Institute of Research and Studies, Faridabad, Haryana, India
| | - Griša Močnik
- Condensed Matter Physics Department, J. Stefan Institute, Ljubljana, Slovenia
| | - Andre S H Prévôt
- Laboratory of Atmospheric Chemistry, Paul Scherrer Institute, 5232 PSI Villigen, Switzerland.
| | - Sachchida N Tripathi
- Department of Civil Engineering, Indian Institute of Technology Kanpur, Kanpur, India.
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16
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Goel V, Hazarika N, Kumar M, Singh V, Thamban NM, Tripathi SN. Variations in Black Carbon concentration and sources during COVID-19 lockdown in Delhi. CHEMOSPHERE 2021; 270:129435. [PMID: 33412356 PMCID: PMC8021479 DOI: 10.1016/j.chemosphere.2020.129435] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/01/2020] [Revised: 12/18/2020] [Accepted: 12/22/2020] [Indexed: 05/08/2023]
Abstract
A nationwide lockdown was imposed in India due to COVID-19 pandemic in five phases from 25th March to May 31, 2020. The lockdown restricted major anthropogenic activities, primarily vehicular and industrial, thereby reducing the particulate matter concentration. This work investigates the variation in Black Carbon (BC) concentration and its sources (primarily Fossil Fuel (ff) burning and Biomass Burning (bb)) over Delhi from 18th February to July 31, 2020, covering one month of pre-lockdown phase, all the lockdown phases, and two months of successive lockdown relaxations. The daily average BC concentration varied from 0.22 to 16.92 μg/m3, with a mean value of 3.62 ± 2.93 μg/m3. During Pre-Lockdown (PL, 18th Feb-24th March 2020), Lockdown-1 (L1, 25th March-14th April 2020), Lockdown-2 (L2, 15th April-3rd May 2020), Lockdown-3 (L3, 4th-17th May 2020), Lockdown-4 (L4, 18th-31st May 2020), Unlock-1 (UN1, June 2020), and Unlock-2 (UN2, July 2020) the average BC concentrations were 7.93, 1.73, 2.59, 3.76, 3.26, 2.07, and 2.70 μg/m3, respectively. During the lockdown and unlock phases, BC decreased up to 78% compared to the PL period. The BC source apportionment studies show that fossil fuel burning was the dominant BC source during the entire sampling period. From L1 to UN2 an increasing trend in BCff contribution was observed (except L3) due to the successive relaxations given to anthropogenic activities. BCff contribution dipped briefly during L3 due to the intensive crop residue burning events in neighboring states. CWT analysis showed that local emission sources were the dominant contributors to BC concentration over Delhi.
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Affiliation(s)
- Vikas Goel
- Department of Mechanical Engineering, Indian Institute of Technology Delhi, New Delhi, 110016, India
| | - Naba Hazarika
- Department of Applied Mechanics, Indian Institute of Technology Delhi, New Delhi, 110016, India
| | - Mayank Kumar
- Department of Mechanical Engineering, Indian Institute of Technology Delhi, New Delhi, 110016, India.
| | - Vikram Singh
- Department of Chemical Engineering, Indian Institute of Technology Delhi, New Delhi, 110016, India.
| | - Navaneeth M Thamban
- Department of Civil Engineering, Indian Institute of Technology Kanpur, Uttar Pradesh, 208016, India
| | - Sachchida Nand Tripathi
- Department of Civil Engineering, Indian Institute of Technology Kanpur, Uttar Pradesh, 208016, India.
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17
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Kahnert M, Kanngießer F. Aerosol optics model for black carbon applicable to remote sensing, chemical data assimilation, and climate modelling. OPTICS EXPRESS 2021; 29:10639-10658. [PMID: 33820195 DOI: 10.1364/oe.422523] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/11/2021] [Accepted: 03/13/2021] [Indexed: 06/12/2023]
Abstract
Aerosol optics models are an integral part of of climate models and of retrieval methods for global remote sensing observations. Such large-scale environmental applications place tight constraints on the affordable model complexity, which are difficult to reconcile with the considerable level of detail that is needed to capture the sensitivity of optical properties to morphological aerosol characteristics. Here, we develop a novel core-grey-shell dimer model and demonstrate its potential for reproducing radiometric and polarimetric properties of black carbon aerosols. The depolarisation is mainly sensitive to the relative size of the monomers, while the optical cross sections depend on the core-shell partitioning of black carbon. The optimum choice of these parameters is fairly stable across particle sizes and soot volume fraction, as is demonstrated by comparison with a more realistic coated aggregate model.
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18
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Chen D, Liao H, Yang Y, Chen L, Wang H. Simulated aging processes of black carbon and its impact during a severe winter haze event in the Beijing-Tianjin-Hebei region. THE SCIENCE OF THE TOTAL ENVIRONMENT 2021; 755:142712. [PMID: 33049531 DOI: 10.1016/j.scitotenv.2020.142712] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/06/2020] [Revised: 09/18/2020] [Accepted: 09/27/2020] [Indexed: 06/11/2023]
Abstract
Black carbon (BC) can mitigate or worsen air pollution by perturbing meteorological conditions. BC aging processes strongly influence the evolution of the particle size, concentration, and optical properties of BC, which determine its influence on meteorology. Here, we use the online coupled Weather Research and Forecasting-Chemistry (WRF-Chem) model to quantify the role of BC aging processes, including physical processes (PP) and absorption enhancement (AE), in causing BC-induced meteorological changes and their associated feedbacks to PM2.5 (particulate matter less than 2.5 μm in diameter) and O3 concentrations during a severe haze event in the Beijing-Tianjin-Hebei (BTH) region during 21-27 February 2014. Our results show that, compared to those from the simulation without PP, the simulated near-surface BC concentration and BC mass loading in the BTH region decreased by 6.6% and 12.1%, respectively, when PP were included. PP increased the proportion of large BC (particle diameter greater than 0.312 μm) below 1000 m from 28 to 33% to 59-64% in the BTH region. When both PP and AE were included in the simulation, the reduction in PBL height due to the BC-PBL interaction was 116.3 m (20.7%), compared to reductions of 75.7 m (13.5%) without AE and 66.6 m (11.9%) without PP and AE. However, during this haze event, anomalous northeasterly winds were produced by the direct radiative effect of BC, which further affected aerosol mixing and transport. Due to their combined impacts on multiple meteorological factors, the direct radiative effects of BC without PP and AE, without AE, and with PP and AE increased the surface concentrations of PM2.5 by 8.3 μg m-3 (by 6.1% relative to the mean value), 6.1 μg m-3 (4.5%) and 9.6 μg m-3 (7.0%), respectively, but decreased the surface O3 concentrations by 2.8 ppbv (7.4%), 4.0 ppbv (9.0%) and 5.0 ppbv (10.8%) on average in the BTH region during 21-27 February 2014.
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Affiliation(s)
- Donglin Chen
- Jiangsu Key Laboratory of Atmospheric Environment Monitoring and Pollution Control, Jiangsu Engineering Technology Research Center of Environmental Cleaning Materials, Collaborative Innovation Center of Atmospheric Environment and Equipment Technology, School of Environmental Science and Engineering, Nanjing University of Information Science & Technology, Nanjing, Jiangsu, China
| | - Hong Liao
- Jiangsu Key Laboratory of Atmospheric Environment Monitoring and Pollution Control, Jiangsu Engineering Technology Research Center of Environmental Cleaning Materials, Collaborative Innovation Center of Atmospheric Environment and Equipment Technology, School of Environmental Science and Engineering, Nanjing University of Information Science & Technology, Nanjing, Jiangsu, China.
| | - Yang Yang
- Jiangsu Key Laboratory of Atmospheric Environment Monitoring and Pollution Control, Jiangsu Engineering Technology Research Center of Environmental Cleaning Materials, Collaborative Innovation Center of Atmospheric Environment and Equipment Technology, School of Environmental Science and Engineering, Nanjing University of Information Science & Technology, Nanjing, Jiangsu, China.
| | - Lei Chen
- Jiangsu Key Laboratory of Atmospheric Environment Monitoring and Pollution Control, Jiangsu Engineering Technology Research Center of Environmental Cleaning Materials, Collaborative Innovation Center of Atmospheric Environment and Equipment Technology, School of Environmental Science and Engineering, Nanjing University of Information Science & Technology, Nanjing, Jiangsu, China
| | - Hailong Wang
- Atmospheric Science and Global Change Division, Pacific Northwest National Laboratory, Richland, WA, USA
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19
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Wu Y, Li J, Jiang C, Xia Y, Tao J, Tian P, Zhou C, Wang C, Xia X, Huang RJ, Zhang R. Spectral absorption properties of organic carbon aerosol during a polluted winter in Beijing, China. THE SCIENCE OF THE TOTAL ENVIRONMENT 2021; 755:142600. [PMID: 33045607 DOI: 10.1016/j.scitotenv.2020.142600] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/13/2020] [Revised: 09/09/2020] [Accepted: 09/21/2020] [Indexed: 06/11/2023]
Abstract
A fraction of organic carbon (OC) is found to exhibit the capability to absorb solar radiation. However, the absorption properties of OC remain poorly characterized partly due to uncertainties in determination methods. In this study, the absorption coefficient (bap) of OC (bap,OC) in Beijing during a polluted winter was estimated on the basis of the combined measurements of black carbon (BC) size distribution and total aerosol bap (bap,meas). The bare BC bap (bap,bareBC) calculated using Mie theory on the basis of measured size distribution exhibited weak wavelength dependence, with a mean absorption Ångström exponent (AAE) of 0.56 ± 0.04 within the 470-660 nm wavelength range, which was lower than the value of 1 commonly used for freshly emitted BC. The calculated bap,bareBC was compared with bap,meas at 950 nm to derive the coating thickness of BC, from which the calculation of coated BC bap (bap,coatBC) within 370-660 nm was based using the core-shell Mie model. Given the thick coatings, the AAE of coated BC, with a mean of 0.53 ± 0.12, was slightly lower than that of bare BC. Subsequently, bap,OC was obtained by subtracting bap,coatBC from bap,meas, accounting for 59.57 ± 4.82% of bap,meas at 370 nm on average. The average mass absorption efficiency of OC was estimated to be 1.48 ± 0.36 m2 g-1 at 370 nm. bap,OC significantly decreased as wavelength increased, deriving an AAE of OC with a mean of 2.72 ± 0.32 within the 370-660 nm range. The level of bap,OC estimated on the basis of a widely used attribution method assuming a constant BC AAE of 1 was ~60% lower than the currently presented value, probably underestimating OC radiative effect by a factor of >3. More accurate estimations of bap,OC based on more advanced measurements and suitable theory calculations are recommended to provide more reliable assessments of OC radiative effects.
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Affiliation(s)
- Yunfei Wu
- Key Laboratory of Middle Atmosphere and Global Environment Observation (LAGEO), Institute of Atmospheric Physics, Chinese Academy of Sciences, Beijing 100029, China.
| | - Jiwei Li
- Key Laboratory of Middle Atmosphere and Global Environment Observation (LAGEO), Institute of Atmospheric Physics, Chinese Academy of Sciences, Beijing 100029, China; University of Chinese Academy of Sciences, Beijing 100049, China
| | - Chen Jiang
- Key Laboratory of Middle Atmosphere and Global Environment Observation (LAGEO), Institute of Atmospheric Physics, Chinese Academy of Sciences, Beijing 100029, China; University of Chinese Academy of Sciences, Beijing 100049, China
| | - Yunjie Xia
- Key Laboratory of Middle Atmosphere and Global Environment Observation (LAGEO), Institute of Atmospheric Physics, Chinese Academy of Sciences, Beijing 100029, China; University of Chinese Academy of Sciences, Beijing 100049, China
| | - Jun Tao
- South China Institute of Environmental Sciences, Ministry of Ecology and Environment, Guangzhou 510530, China
| | - Ping Tian
- Beijing Weather Modification Office, Beijing 100089, China
| | - Chang Zhou
- Key Laboratory of Middle Atmosphere and Global Environment Observation (LAGEO), Institute of Atmospheric Physics, Chinese Academy of Sciences, Beijing 100029, China; University of Chinese Academy of Sciences, Beijing 100049, China
| | - Chaoying Wang
- Key Laboratory of Middle Atmosphere and Global Environment Observation (LAGEO), Institute of Atmospheric Physics, Chinese Academy of Sciences, Beijing 100029, China; University of Chinese Academy of Sciences, Beijing 100049, China
| | - Xiangao Xia
- Key Laboratory of Middle Atmosphere and Global Environment Observation (LAGEO), Institute of Atmospheric Physics, Chinese Academy of Sciences, Beijing 100029, China; Xianghe Observatory of Whole Atmosphere, Institute of Atmospheric Physics, Chinese Academy of Sciences, Xianghe 065400, China
| | - Ru-Jin Huang
- Key Laboratory of Aerosol Chemistry and Physics, State Key Laboratory of Loess and Quaternary Geology, Institute of Earth Environment, Chinese Academy of Sciences, Xi'an 710061, China
| | - Renjian Zhang
- Key Laboratory of Middle Atmosphere and Global Environment Observation (LAGEO), Institute of Atmospheric Physics, Chinese Academy of Sciences, Beijing 100029, China; Xianghe Observatory of Whole Atmosphere, Institute of Atmospheric Physics, Chinese Academy of Sciences, Xianghe 065400, China
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20
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The Ångström Exponent and Single-Scattering Albedo of Black Carbon: Effects of Different Coating Materials. ATMOSPHERE 2020. [DOI: 10.3390/atmos11101103] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
Abstract
In this work, the absorption Ångström exponent (AAE), extinction Ångström exponent (EAE), and single-scattering albedo (SSA) of black carbon (BC) with different coating materials are numerically investigated. BC with different coating materials can provide explanations for the small AAE, small EAE, and large AAE observed in the atmosphere, which is difficult to be explained by bare BC aggregate models. The addition of organic carbon (OC) does not necessarily increase AAE due to the transformation of BC morphologies and the existence of non-absorbing OC. The addition of coating materials does also not necessarily decrease EAE. While the addition of coating materials can increase the total size of BC-containing particles, the effective refractive index can be modified by introducing the coating materials, so increases the EAE. We found that it is not possible to differentiate between thinly- and heavily-coated BC based on EAE or AAE alone. On the other hand, SSA is much less sensitive to the size and can provide much more information for distinguishing heavily-coated BC from thinly-coated BC. For BC with different coating materials and mixing states, AAE, EAE, and SSA show rather different sensitivities to particle size and composition ratios, and their spectral-dependences also exhibit distinct differences. Different AAE and EAE trends with BC/OC ratio were also found for BC with different coating materials and mixing states. Furthermore, we also found empirical fittings for AAE, EAE, SSA, and optical cross-sections, which may be useful for retrieving the size information based on the optical measurements.
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21
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Wu Y, Cheng T, Pan X, Zheng L, Shi S, Liu H. The role of biomass burning states in light absorption enhancement of carbonaceous aerosols. Sci Rep 2020; 10:12829. [PMID: 32733027 PMCID: PMC7393073 DOI: 10.1038/s41598-020-69611-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2020] [Accepted: 07/06/2020] [Indexed: 12/03/2022] Open
Abstract
Carbonaceous aerosols, which are emitted from biomass burning, significantly contribute to the Earth's radiation balance. Radiative forcing caused by biomass burning has been poorly qualified, which is largely attributed to uncertain absorption enhancement values (Eabs) of black carbon (BC) aerosols. Laboratory measurements and theoretical modelling indicate a significant value of Eabs; but this enhancement is observed to be negligible in the ambient environment, implying that models may overestimate global warming due to BC. Here, we present an aggregate model integrating BC aerosol ensembles with different morphologies and mixing states and report a quantitative analysis of the BC Eabs from different combustion states during biomass burning. We show that the BC Eabs produced by flaming combustion may be up to two times more than those produced by smouldering combustion, suggesting that the particle morphology and mixing state of freshly emitted BC aerosols is an important source of the contrasting values of Eabs. The particle morphology of freshly emitted BC aerosols is widely assumed to be bare in models, which is rare in the ambient environment and leads to small estimates of Eabs by field observations. We conclude that the exact description of freshly emitted carbonaceous aerosols plays an important role in constraining aerosol radiative forcing.
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Affiliation(s)
- Yu Wu
- State Key Laboratory of Remote Sensing Science, Aerospace Information Research Institute, Chinese Academy of Sciences, No.9 Dengzhuangnan Road, Haidian District, Beijing, 100094, China
| | - Tianhai Cheng
- State Key Laboratory of Remote Sensing Science, Aerospace Information Research Institute, Chinese Academy of Sciences, No.9 Dengzhuangnan Road, Haidian District, Beijing, 100094, China.
| | - Xiaole Pan
- State Key Laboratory of Atmospheric Boundary Layer Physics and Atmospheric Chemistry, Institute of Atmospheric Physics, Chinese Academy of Sciences, No.40 Huayanli, Chaoyang District, Beijing, 100029, China
| | - Lijuan Zheng
- Land Satellite Remote Sensing Application Center, Ministry of Natural Resources of China, No.1 Baishengcun, Haidian District, Beijing, 100048, China
| | - Shuaiyi Shi
- State Key Laboratory of Remote Sensing Science, Aerospace Information Research Institute, Chinese Academy of Sciences, No.9 Dengzhuangnan Road, Haidian District, Beijing, 100094, China
| | - Hang Liu
- State Key Laboratory of Atmospheric Boundary Layer Physics and Atmospheric Chemistry, Institute of Atmospheric Physics, Chinese Academy of Sciences, No.40 Huayanli, Chaoyang District, Beijing, 100029, China
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22
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Zheng G, Sedlacek AJ, Aiken AC, Feng Y, Watson TB, Raveh-Rubin S, Uin J, Lewis ER, Wang J. Long-range transported North American wildfire aerosols observed in marine boundary layer of eastern North Atlantic. ENVIRONMENT INTERNATIONAL 2020; 139:105680. [PMID: 32272293 DOI: 10.1016/j.envint.2020.105680] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/07/2019] [Revised: 03/18/2020] [Accepted: 03/20/2020] [Indexed: 06/11/2023]
Abstract
Wildfire is a major source of biomass burning aerosols, which greatly impact Earth climate. Tree species in North America (NA) boreal forests can support high-intensity crown fires, resulting in elevated injection height and longer lifetime (on the order of months) of the wildfire aerosols. Given the long lifetime, the properties of aged NA wildfire aerosols are required to understand and quantify their effects on radiation and climate. Here we present comprehensive characterization of climatically relevant properties, including optical properties and cloud condensation nuclei (CCN) activities of aged NA wildfire aerosols, emitted from the record-breaking Canadian wildfires in August 2017. Despite the extreme injection height of ~12 km, some of the wildfire plumes descended into the marine boundary layer in the eastern North Atlantic over a period of ~2 weeks, owing to the dry intrusions behind mid-latitude cyclones. The aged wildfire aerosols have high single scattering albedos at 529 nm (ω529; 0.92-0.95) while low absorption Ångström exponents (Åabs) at 464 nm/648 nm (0.7-0.9). In comparison, Åabs of fresh/slightly aged ones are typically 1.4-3.5. This low Åabs indicates a nearly complete loss of brown carbon, likely due to bleaching and/or evaporation, during the long-range transport. The nearly complete loss suggests that on global average, direct radiative forcing of BrC may be minor. Combining Mie calculations and the measured aerosol hygroscopicity, volatility and size distributions, we show that the high ω529 and low Åabs values are best explained by an external mixture of non-absorbing organic particles and absorbing particles of large BC cores (>~110 nm diameter) with thick non-absorbing coatings. The accelerated descent of the wildfire plume also led to strong increase of CCN concentration at the supersaturation levels representative of marine low clouds. The hygroscopicity parameter, κCCN, of the aged wildfire aerosols varies from 0.2 to 0.4, substantially lower than that of background marine boundary layer aerosols. However, the high fraction of particles with large diameter (i.e., within accumulation size ranges, ~100-250 nm) compensates for the low values of κ, and as a result, the aged NA wildfire aerosols contribute more efficiently to CCN population. These results provide direct evidence that the long-range transported NA wildfires can strongly influence CCN concentration in remote marine boundary layer, therefore the radiative properties of marine low clouds. Given the expected increases of NA wildfire intensity and frequency and regular occurrence of dry intrusion following mid-latitude cyclones, the influence of NA wildfire aerosols on CCN and clouds in remote marine environment need to be further examined.
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Affiliation(s)
- Guangjie Zheng
- Center for Aerosol Science and Engineering, Department of Energy, Environmental and Chemical Engineering, Washington University in St. Louis, MO, USA; Environmental and Climate Science Department, Brookhaven National Laboratory, Upton, NY, USA
| | - Arthur J Sedlacek
- Environmental and Climate Science Department, Brookhaven National Laboratory, Upton, NY, USA
| | - Allison C Aiken
- Earth System Observations, Los Alamos National Laboratory, Los Alamos, NM, USA
| | - Yan Feng
- Environmental Science Division, Argonne National Laboratory, Lemont, IL, USA
| | - Thomas B Watson
- Environmental and Climate Science Department, Brookhaven National Laboratory, Upton, NY, USA
| | - Shira Raveh-Rubin
- Earth and Planetary Sciences, Weizmann Institute of Science, Rehovot, Israel
| | - Janek Uin
- Environmental and Climate Science Department, Brookhaven National Laboratory, Upton, NY, USA
| | - Ernie R Lewis
- Environmental and Climate Science Department, Brookhaven National Laboratory, Upton, NY, USA
| | - Jian Wang
- Center for Aerosol Science and Engineering, Department of Energy, Environmental and Chemical Engineering, Washington University in St. Louis, MO, USA; Environmental and Climate Science Department, Brookhaven National Laboratory, Upton, NY, USA.
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23
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One-Year Measurements of Equivalent Black Carbon, Optical Properties, and Sources in the Urumqi River Valley, Tien Shan, China. ATMOSPHERE 2020. [DOI: 10.3390/atmos11050478] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Equivalent black carbon (EBC) was measured with a seven-wavelength Aethalometer (AE-31) in the Urumqi River Valley, eastern Tien Shan, China. This is the first high-resolution, online measurement of EBC conducted in the eastern Tien Shan allowing analysis of the seasonal and hourly variations of the light absorption properties of EBC. Results showed that the highest concentrations of EBC were in autumn, followed by those in summer. The hourly variations of EBC showed two plateaus during 8:00–9:00 h local time (LT) and 16:00–19:00 h LT, respectively. The contribution of biomass burning to EBC in winter and spring was higher than in summer and autumn. The planetary boundary layer height (PBLH) showed an inverse relationship with EBC concentrations, suggesting that the reduction of the PBLH leads to enhanced EBC. The aerosol optical depths (AOD) over the Urumqi River Valley, derived from the Moderate Resolution Imaging Spectroradiometer (MODIS) data and back trajectory analysis, showed that the pollution from Central Asia was more likely to affect the atmosphere of Tien Shan in summer and autumn. This suggests that long-distance transported pollutants from Central Asia could also be potential contributors to EBC concentrations in the Urumqi River Valley, the same as local anthropogenic activities.
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Radiative absorption enhancements by black carbon controlled by particle-to-particle heterogeneity in composition. Proc Natl Acad Sci U S A 2020; 117:5196-5203. [PMID: 32098848 PMCID: PMC7071900 DOI: 10.1073/pnas.1919723117] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Absorption by black carbon strongly affects regional and global climate. Yet, large discrepancies between standard model predictions and regionally specific observations—often with observed absorption lower than expected—raise questions about current understanding of black carbon absorption and its atmospheric impacts. Through a combination of measurement and modeling, our analysis resolves the discrepancy by showing that particular laboratory designs or atmospheric conditions engender distinct compositional heterogeneity among particles containing black carbon. Lower-than-expected absorption results largely from increased heterogeneity, although slightly lowered absorption occurs even in a purely homogeneous system. This work provides a framework that explains globally disparate observations and that can be used to improve estimates of black carbon’s global impact. Black carbon (BC) absorbs solar radiation, leading to a strong but uncertain warming effect on climate. A key challenge in modeling and quantifying BC’s radiative effect on climate is predicting enhancements in light absorption that result from internal mixing between BC and other aerosol components. Modeling and laboratory studies show that BC, when mixed with other aerosol components, absorbs more strongly than pure, uncoated BC; however, some ambient observations suggest more variable and weaker absorption enhancement. We show that the lower-than-expected enhancements in ambient measurements result from a combination of two factors. First, the often used spherical, concentric core-shell approximation generally overestimates the absorption by BC. Second, and more importantly, inadequate consideration of heterogeneity in particle-to-particle composition engenders substantial overestimation in absorption by the total particle population, with greater heterogeneity associated with larger model–measurement differences. We show that accounting for these two effects—variability in per-particle composition and deviations from the core-shell approximation—reconciles absorption enhancement predictions with laboratory and field observations and resolves the apparent discrepancy. Furthermore, our consistent model framework provides a path forward for improving predictions of BC’s radiative effect on climate.
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25
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Tzabari M, Lin W, Lerner A, Iluz D, Haspel C. Sensitivity study on the contribution of scattering by randomly oriented nonspherical hydrosols to linear polarization in clear to semi-turbid shallow waters. APPLIED OPTICS 2019; 58:7258-7279. [PMID: 31504002 DOI: 10.1364/ao.58.007258] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/20/2019] [Accepted: 07/26/2019] [Indexed: 06/10/2023]
Abstract
The influence of hydrosol nonsphericity on the polarization characteristics of light under water is investigated by combining accurate single-scattering models for randomly oriented spheroidal scatterers with a radiative transfer model that employs Stokes formalism and considers refraction of direct unpolarized solar radiation and 100% linearly polarized radiation at the air-water interface followed by single scattering. Variations in what we call the "linear polarization phase function" (the degree of linear polarization as a function of scattering angle and the angle of linear polarization as a function of scattering angle) are examined for a wide range of spheroid aspect ratios and complex refractive indices of hydrosols. Implications for polarization-sensitive marine organisms and for remote sensing of the marine environment are discussed.
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26
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Abstract
Aerosol mixing state significantly affects concentrations of cloud condensation nuclei (CCN), wet removal rates, thermodynamic properties, heterogeneous chemistry, and aerosol optical properties, with implications for human health and climate. Over the last two decades, significant research effort has gone into finding computationally-efficient methods for representing the most important aspects of aerosol mixing state in air pollution, weather prediction, and climate models. In this review, we summarize the interactions between mixing-state and aerosol hygroscopicity, optical properties, equilibrium thermodynamics and heterogeneous chemistry. We focus on the effects of simplified assumptions of aerosol mixing state on CCN concentrations, wet deposition, and aerosol absorption. We also summarize previous approaches for representing aerosol mixing state in atmospheric models, and we make recommendations regarding the representation of aerosol mixing state in future modelling studies.
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27
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Han C, Li SM, Liu P, Lee P. Size Dependence of the Physical Characteristics of Particles Containing Refractory Black Carbon in Diesel Vehicle Exhaust. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2019; 53:137-145. [PMID: 30516049 DOI: 10.1021/acs.est.8b04603] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
The number and mass size distributions of refractory black carbon (rBC) cores in particles emitted from a diesel vehicle were investigated as a function of particle mobility diameter ( dmob) using a single particle soot photometer (SP2) and a differential mobility analyzer (DMA). The thickness and mass of coatings on the rBC cores were characterized. On the basis of the SP2 and DMA results, the physical properties of particles containing rBC, including effective density (ρeff), mass-mobility scaling exponent ( Dm), dynamic shape factor (χ), and mass absorption cross section (MAC), were derived as a function of dmob. At each dmob, the count median diameter (CMD) of the rBC cores was essentially the same as their mass median diameter (MMD), which increased linearly with dmob. The mass of the rBC cores was proportional to the cubic of their dmob. However, coating thickness on rBC cores remained unchanged with dmob, with an average thickness of 28.72 ± 4.81 nm. For particles containing rBC, ρeff decreased and χ increased with dmob. The Dm of particles containing rBC was calculated to be 2.09. At 355 and 532 nm wavelengths, the MAC of the diesel particles containing rBC was inversely dependent on dmob.
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Affiliation(s)
- Chong Han
- Air Quality Research Division , Environment and Climate Change Canada , 4905 Dufferin Street , Toronto , Ontario M3H 5T4 , Canada
| | - Shao-Meng Li
- Air Quality Research Division , Environment and Climate Change Canada , 4905 Dufferin Street , Toronto , Ontario M3H 5T4 , Canada
| | - Peter Liu
- Air Quality Research Division , Environment and Climate Change Canada , 4905 Dufferin Street , Toronto , Ontario M3H 5T4 , Canada
| | - Patrick Lee
- Air Quality Research Division , Environment and Climate Change Canada , 4905 Dufferin Street , Toronto , Ontario M3H 5T4 , Canada
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28
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Chen DH, Alphones A. Characterization of the incipient smoke point for steam-/air-assisted and nonassisted flares. JOURNAL OF THE AIR & WASTE MANAGEMENT ASSOCIATION (1995) 2019; 69:119-130. [PMID: 30230968 DOI: 10.1080/10962247.2018.1525443] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/25/2018] [Revised: 07/06/2018] [Accepted: 09/14/2018] [Indexed: 06/08/2023]
Abstract
Flares are important safety devices for pressure relief; at the same time, flares are a significant point source for soot and highly reactive volatile organic compounds (HRVOCs). Currently, simple guidelines for flare operations to maintain high combustion efficiency (CE) remain elusive. This paper fills the gap by investigating the characteristics of the incipient smoke point (ISP), which is widely recognized as the condition for good combustion. This study characterizes the ISP in terms of 100-% combustion inefficiency (CE), percent opacity, absorbance, air assist, steam assist, air equivalence ratio, steam equivalence ratio, exit velocity, vent gas net heating value, and combustion zone net heating value. Flame lengths were calculated for buoyant and momentum-dominated plumes under calm and windy conditions at stable and neutral atmosphere. Opacity was calculated using the Beer-Lambert law based on soot concentration, flame diameter, and mass-specific extinction cross section of soot. The calculated opacity and absorbance were found to be lognormally distributed. Linear relations were established for soot yield versus absorptivity with R2 > 0.99 and power-law relations for opacity versus soot emission rate with R2 ≥ 0.97 for steam-assisted, air-assisted, and nonassisted flares. The characterized steam/air assists, combustion zone/vent gas heating values, exit velocity, steam, and air equivalence ratios for the incipient smoke point will serve as a useful guideline for efficient flare operations.Implications: A Recent EPA rule requires an evaluation of visible emissions in terms of opacity in compliance with the standards. In this paper, visible emissions such as soot particles are characterized in terms of opacity at ISP. Since ISP is widely recognized as most efficient flare operation for high combustion efficiency (CE)/destruction efficiency (DE) with initial soot particles formed in the flame, this characterization provides a useful guideline for flare operators in the refinery, oil and gas, and chemical industries to sustain smokeless and high combustion efficiency flaring in compliance with recent EPA regulations, in addition to protecting the environment.
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Affiliation(s)
- Daniel H Chen
- Computational Fluid Dynamics Lab, Dan F. Smith Department of Chemical Engineering, Lamar University, Beaumont, Texas, USA
| | - Arokiaraj Alphones
- Computational Fluid Dynamics Lab, Dan F. Smith Department of Chemical Engineering, Lamar University, Beaumont, Texas, USA
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29
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Saliba G, Subramanian R, Bilsback K, L'Orange C, Volckens J, Johnson M, Robinson AL. Aerosol Optical Properties and Climate Implications of Emissions from Traditional and Improved Cookstoves. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2018; 52:13647-13656. [PMID: 30373367 DOI: 10.1021/acs.est.8b05434] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
Cookstove emissions are a major global source of black carbon but their impact on climate is uncertain because of limited understanding of their optical properties. We measured optical properties of fresh aerosol emissions from 32 different stove/fuel combinations, ranging from simple open fires to high-performing forced-draft stoves. Stoves were tested in the laboratory using the firepower sweep protocol, which measures emissions across the entire range of functional firepower. There is large variability in measured optical properties across the entire range of firepower. This variability is strongly correlated with black carbon-to-particulate matter mass ratio (BC/PM). In comparison, stove type, fuel, and operational metrics were poor predictors of optical properties. We developed parametrizations of the mass absorption cross-section, the absorption angstrom exponent, and the single scattering albedo of fresh emissions as a function of BC/PM. These parametrizations, derived from laboratory data, also reproduce previously reported field measurements of optical properties of real-world cooking emissions. We combined our new parametrizations of intensive optical properties with published emissions data to estimate the direct radiative effect of emissions for different stove technologies. Our data suggest that so-called "improved" stove reduce CO2 equivalent emission (i.e., climate benefits) by 20-30% compared to traditional stoves.
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Affiliation(s)
- Georges Saliba
- Carnegie Mellon University , 5000 Forbes Avenue , Pittsburgh , Pennsylvania 15213 , United States
| | - R Subramanian
- Carnegie Mellon University , 5000 Forbes Avenue , Pittsburgh , Pennsylvania 15213 , United States
| | - Kelsey Bilsback
- Colorado State University , 430 North College Avenue , Fort Collins , Colorado 80524 , United States
| | - Christian L'Orange
- Colorado State University , 430 North College Avenue , Fort Collins , Colorado 80524 , United States
| | - John Volckens
- Colorado State University , 430 North College Avenue , Fort Collins , Colorado 80524 , United States
| | - Michael Johnson
- Berkeley Air Monitoring Group , 1900 Addison Street , Berkeley , California 94704 , United States
| | - Allen L Robinson
- Carnegie Mellon University , 5000 Forbes Avenue , Pittsburgh , Pennsylvania 15213 , United States
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30
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Mousavi A, Sowlat MH, Hasheminassab S, Polidori A, Sioutas C. Spatio-temporal trends and source apportionment of fossil fuel and biomass burning black carbon (BC) in the Los Angeles Basin. THE SCIENCE OF THE TOTAL ENVIRONMENT 2018; 640-641:1231-1240. [PMID: 30021288 DOI: 10.1016/j.scitotenv.2018.06.022] [Citation(s) in RCA: 27] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/28/2018] [Revised: 05/31/2018] [Accepted: 06/02/2018] [Indexed: 06/08/2023]
Abstract
In this study, we evaluated the spatial and temporal trends of black carbon (BC) in the Los Angeles Basin between 2012-2013 and 2016-2017. BC concentrations were measured in seven wavelengths using Aethalometers (AE33) at four sites, including central Los Angeles (CELA), Anaheim, Fontana, and Riverside. Sources of BC were quantified using the equivalent black carbon (EBC) model. Results indicate that total BC concentrations nearly doubled in colder period compared to the warm period. Source apportionment results revealed that fossil fuel combustion has higher annual contributions (ranging from 82% in Riverside to 91% in CELA) than biomass burning (ranging from 9.3% in CELA to 18.7% in Riverside) to the total BC concentrations at all sites. This trend was more clearly observed at the sites closer to major freeways, such as CELA and Anaheim. The relative contribution of fossil fuel to total BC concentrations was higher in the warm period, whereas biomass burning had higher contributions in the colder period. The diurnal variation of fossil-fuel-originated BC (BCff) to the total BC concentrations revealed major rises during the traffic rush hours, especially in the warm period. In contrast, the fraction of BC originating from biomass burning (BCbb) peaked at nighttime, particularly in the cold period, reaching values as high as 25-30% of total BC concentration. Moreover, we observed a clear decrease in both absolute BC concentrations as well as relative contributions of BCff to total BC concentrations from 2012-2013 to 2016-2017, which can be attributed to the implementation of strict regulations in California to reduce transportation-related PM emissions. Results from the present study suggest that as these regulations become increasingly stricter, the relative contributions of traffic sources to BC also decrease, thereby making the impact of non-fossil fuel combustion sources, such as biomass burning, to the overall BC levels more significant.
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Affiliation(s)
- Amirhosein Mousavi
- University of Southern California, Department of Civil and Environmental Engineering, Los Angeles, CA, USA.
| | - Mohammad H Sowlat
- University of Southern California, Department of Civil and Environmental Engineering, Los Angeles, CA, USA.
| | | | - Andrea Polidori
- South Coast Air Quality Management District, Diamond Bar, CA, USA.
| | - Constantinos Sioutas
- University of Southern California, Department of Civil and Environmental Engineering, Los Angeles, CA, USA.
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31
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Hu T, Cao J, Zhu C, Zhao Z, Liu S, Zhang D. Morphologies and elemental compositions of local biomass burning particles at urban and glacier sites in southeastern Tibetan Plateau: Results from an expedition in 2010. THE SCIENCE OF THE TOTAL ENVIRONMENT 2018; 628-629:772-781. [PMID: 29454217 DOI: 10.1016/j.scitotenv.2018.02.073] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/26/2017] [Revised: 02/07/2018] [Accepted: 02/07/2018] [Indexed: 06/08/2023]
Abstract
Many studies indicate that the atmospheric environment over the southern part of the Tibetan Plateau is influenced by aged biomass burning particles that are transported over long distances from South Asia. However, our knowledge of the particles emitted locally (within the plateau region) is poor. We collected aerosol particles at four urban sites and one remote glacier site during a scientific expedition to the southeastern Tibetan Plateau in spring 2010. Weather and backward trajectory analyses indicated that the particles we collected were more likely dominated by particles emitted within the plateau. The particles were examined using an electron microscope and identified according to their sizes, shapes and elemental compositions. At three urban sites where the anthropogenic particles were produced mainly by the burning of firewood, soot aggregates were in the majority and made up >40% of the particles by number. At Lhasa, the largest city on the Tibetan Plateau, tar balls and mineral particles were also frequently observed because of the use of coal and natural gas, in addition to biofuel. In contrast, at the glacier site, large numbers of chain-like soot aggregates (~25% by number) were noted. The morphologies of these aggregates were similar to those of freshly emitted ones at the urban sites; moreover, physically or chemically processed ageing was rarely confirmed. These limited observations suggest that the biomass burning particles age slowly in the cold, dry plateau air. Anthropogenic particles emitted locally within the elevated plateau region may thus affect the environment within glaciated areas in Tibet differently than anthropogenic particles transported from South Asia.
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Affiliation(s)
- Tafeng Hu
- Key Laboratory of Aerosol Chemistry & Physics, SKLLQG, Institute of Earth Environment, Chinese Academy of Sciences, Xi'an 710061, China
| | - Junji Cao
- Key Laboratory of Aerosol Chemistry & Physics, SKLLQG, Institute of Earth Environment, Chinese Academy of Sciences, Xi'an 710061, China.
| | - Chongshu Zhu
- Key Laboratory of Aerosol Chemistry & Physics, SKLLQG, Institute of Earth Environment, Chinese Academy of Sciences, Xi'an 710061, China
| | - Zhuzi Zhao
- Key Laboratory of Aerosol Chemistry & Physics, SKLLQG, Institute of Earth Environment, Chinese Academy of Sciences, Xi'an 710061, China
| | - Suixin Liu
- Key Laboratory of Aerosol Chemistry & Physics, SKLLQG, Institute of Earth Environment, Chinese Academy of Sciences, Xi'an 710061, China
| | - Daizhou Zhang
- Faculty of Environmental and Symbiotic Sciences, Prefectural University of Kumamoto, Kumamoto 862-8502, Japan.
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32
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Cheng Y, He KB, Engling G, Weber R, Liu JM, Du ZY, Dong SP. Brown and black carbon in Beijing aerosol: Implications for the effects of brown coating on light absorption by black carbon. THE SCIENCE OF THE TOTAL ENVIRONMENT 2017; 599-600:1047-1055. [PMID: 28511349 DOI: 10.1016/j.scitotenv.2017.05.061] [Citation(s) in RCA: 40] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/15/2017] [Revised: 04/27/2017] [Accepted: 05/06/2017] [Indexed: 05/08/2023]
Abstract
Brown carbon (BrC) is increasingly included in climate models as an emerging category of particulate organic compounds that can absorb solar radiation efficiently at specific wavelengths. Water-soluble organic carbon (WSOC) has been commonly used as a surrogate for BrC; however, it only represents a limited fraction of total organic carbon (OC) mass, which could be as low as about 20% in urban atmosphere. Using methanol as the extraction solvent, up to approximately 90% of the OC in Beijing aerosol was isolated and measured for absorption spectra over the ultraviolet-to-visible wavelength range. Compared to methanol-soluble OC (MSOC), WSOC underestimated BrC absorption by about 50% at 365nm. The mass absorption efficiencies measured for BrC in Beijing aerosol were converted to the imaginary refractive indices of BrC and subsequently used to compute BrC coating-induced enhancement of light absorption (Eabs) by black carbon. Eabs attributed to lensing was reduced in the case of BrC coating relative to that caused by purely-scattering coating. However, this reduction was overwhelmed by the effect of BrC shell absorption, indicating that the overall effect of BrC coating was an increase in Eabs. Methanol extraction significantly reduced charring of OC during thermal-optical analysis, leading to a large increase in the measured elemental carbon (EC) mass and an apparent improvement in the consistency of EC measurements by different thermal-optical methods.
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Affiliation(s)
- Yuan Cheng
- State Key Joint Laboratory of Environment Simulation and Pollution Control, School of Environment, Tsinghua University, Beijing, China.
| | - Ke-Bin He
- State Key Joint Laboratory of Environment Simulation and Pollution Control, School of Environment, Tsinghua University, Beijing, China.
| | - Guenter Engling
- Division of Atmospheric Sciences, Desert Research Institute, Reno, NV, USA
| | - Rodney Weber
- School of Earth and Atmospheric Sciences, Georgia Institute of Technology, Atlanta, GA, USA
| | - Jiu-Meng Liu
- Atmospheric Sciences and Global Change Division, Pacific Northwest National Laboratory, Richland, WA, USA.
| | - Zhen-Yu Du
- National Research Center for Environmental Analysis and Measurement (CNEAC), Beijing, China.
| | - Shu-Ping Dong
- National Research Center for Environmental Analysis and Measurement (CNEAC), Beijing, China
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Deng W, Hu Q, Liu T, Wang X, Zhang Y, Song W, Sun Y, Bi X, Yu J, Yang W, Huang X, Zhang Z, Huang Z, He Q, Mellouki A, George C. Primary particulate emissions and secondary organic aerosol (SOA) formation from idling diesel vehicle exhaust in China. THE SCIENCE OF THE TOTAL ENVIRONMENT 2017; 593-594:462-469. [PMID: 28355592 DOI: 10.1016/j.scitotenv.2017.03.088] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/06/2017] [Revised: 03/08/2017] [Accepted: 03/09/2017] [Indexed: 05/16/2023]
Abstract
In China diesel vehicles dominate the primary emission of particulate matters from on-road vehicles, and they might also contribute substantially to the formation of secondary organic aerosols (SOA). In this study tailpipe exhaust of three typical in-use diesel vehicles under warm idling conditions was introduced directly into an indoor smog chamber with a 30m3 Teflon reactor to characterize primary emissions and SOA formation during photo-oxidation. The emission factors of primary organic aerosol (POA) and black carbon (BC) for the three types of Chinese diesel vehicles ranged 0.18-0.91 and 0.15-0.51gkg-fuel-1, respectively; and the SOA production factors ranged 0.50-1.8gkg-fuel-1 and SOA/POA ratios ranged 0.7-3.7 with an average of 2.2. The fuel-based POA emission factors and SOA production factors from this study for idling diesel vehicle exhaust were 1-3 orders of magnitude higher than those reported in previous studies for idling gasoline vehicle exhaust. The emission factors for total particle numbers were 0.65-4.0×1015particleskg-fuel-1, and particles with diameters less than 50nm dominated in total particle numbers. Traditional C2-C12 precursor non-methane hydrocarbons (NMHCs) could only explain less than 3% of the SOA formed during aging and contribution from other precursors including intermediate volatile organic compounds (IVOC) needs further investigation.
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Affiliation(s)
- Wei Deng
- State Key Laboratory of Organic Geochemistry and Guangdong Key Laboratory of Environmental Protection and Resources Utilization, Guangzhou Institute of Geochemistry, Chinese Academy of Sciences, Guangzhou 510640, China; University of Chinese Academy of Sciences, Beijing 100049, China
| | - Qihou Hu
- State Key Laboratory of Organic Geochemistry and Guangdong Key Laboratory of Environmental Protection and Resources Utilization, Guangzhou Institute of Geochemistry, Chinese Academy of Sciences, Guangzhou 510640, China
| | - Tengyu Liu
- State Key Laboratory of Organic Geochemistry and Guangdong Key Laboratory of Environmental Protection and Resources Utilization, Guangzhou Institute of Geochemistry, Chinese Academy of Sciences, Guangzhou 510640, China
| | - Xinming Wang
- State Key Laboratory of Organic Geochemistry and Guangdong Key Laboratory of Environmental Protection and Resources Utilization, Guangzhou Institute of Geochemistry, Chinese Academy of Sciences, Guangzhou 510640, China; Center for Excellence in Regional Atmospheric Environment, Institute of Urban Environment, Chinese Academy of Sciences, Xiamen 361021, China.
| | - Yanli Zhang
- State Key Laboratory of Organic Geochemistry and Guangdong Key Laboratory of Environmental Protection and Resources Utilization, Guangzhou Institute of Geochemistry, Chinese Academy of Sciences, Guangzhou 510640, China; Center for Excellence in Regional Atmospheric Environment, Institute of Urban Environment, Chinese Academy of Sciences, Xiamen 361021, China
| | - Wei Song
- State Key Laboratory of Organic Geochemistry and Guangdong Key Laboratory of Environmental Protection and Resources Utilization, Guangzhou Institute of Geochemistry, Chinese Academy of Sciences, Guangzhou 510640, China
| | - Yele Sun
- Institute of Atmospheric Physics, Chinese Academy of Sciences, Beijing 100029, China
| | - Xinhui Bi
- State Key Laboratory of Organic Geochemistry and Guangdong Key Laboratory of Environmental Protection and Resources Utilization, Guangzhou Institute of Geochemistry, Chinese Academy of Sciences, Guangzhou 510640, China
| | - Jianzhen Yu
- Division of Environment, Hong Kong University of Science & Technology, Clear Water Bay, Kowloon, Hong Kong, China
| | - Weiqiang Yang
- State Key Laboratory of Organic Geochemistry and Guangdong Key Laboratory of Environmental Protection and Resources Utilization, Guangzhou Institute of Geochemistry, Chinese Academy of Sciences, Guangzhou 510640, China; University of Chinese Academy of Sciences, Beijing 100049, China
| | - Xinyu Huang
- State Key Laboratory of Organic Geochemistry and Guangdong Key Laboratory of Environmental Protection and Resources Utilization, Guangzhou Institute of Geochemistry, Chinese Academy of Sciences, Guangzhou 510640, China; University of Chinese Academy of Sciences, Beijing 100049, China
| | - Zhou Zhang
- State Key Laboratory of Organic Geochemistry and Guangdong Key Laboratory of Environmental Protection and Resources Utilization, Guangzhou Institute of Geochemistry, Chinese Academy of Sciences, Guangzhou 510640, China
| | - Zhonghui Huang
- State Key Laboratory of Organic Geochemistry and Guangdong Key Laboratory of Environmental Protection and Resources Utilization, Guangzhou Institute of Geochemistry, Chinese Academy of Sciences, Guangzhou 510640, China; University of Chinese Academy of Sciences, Beijing 100049, China
| | - Quanfu He
- State Key Laboratory of Organic Geochemistry and Guangdong Key Laboratory of Environmental Protection and Resources Utilization, Guangzhou Institute of Geochemistry, Chinese Academy of Sciences, Guangzhou 510640, China
| | - Abdelwahid Mellouki
- Institut de Combustion, Aérothermique, Réactivité et Environnement (ICARE), CNRS, 45071 Orléans Cedex 02, France
| | - Christian George
- Institut de Recherches sur la Catalyse et l'Environnement de Lyon (IRCELYON), CNRS, UMR5256, Villeurbanne F-69626, France
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34
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Leung KK, Schnitzler EG, Dastanpour R, Rogak SN, Jäger W, Olfert JS. Relationship between Coating-Induced Soot Aggregate Restructuring and Primary Particle Number. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2017; 51:8376-8383. [PMID: 28661663 DOI: 10.1021/acs.est.7b01140] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
The restructuring of monodisperse soot aggregates due to coatings of secondary organic aerosol (SOA) was investigated in a series of photo-oxidation chamber experiments. Soot aggregates were generated by one of three sources (an ethylene premixed burner, a methane inverted diffusion burner, or a diesel generator), treated by denuding, size-selected by a differential mobility analyzer, and injected into a smog chamber, where they were exposed to the photo-oxidation products of p-xylene, which partitioned to form SOA coatings. The evolution of aggregates from their initial to final morphologies was investigated in situ by mobility and mass measurements and ex situ by transmission electron microscopy. At a given initial aggregate mobility diameter, diesel aggregates are less dense and composed of smaller primary particles than those generated by the two burners, and they restructure to a smaller final mobility diameter. Remarkably, the final degrees of restructuring of aggregates from all three sources exhibit the same linear dependence on the number of primary particles per aggregate. The observed linear relationship, valid for the atmospherically relevant SOA coating investigated here, could allow modelers to predict the evolution of aggregate morphology based on a single property of the aggregates.
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Affiliation(s)
- Kaiser K Leung
- Department of Mechanical Engineering, University of Alberta , Edmonton, Alberta, Canada T6G 2G8
| | - Elijah G Schnitzler
- Department of Chemistry, University of Alberta , Edmonton, Alberta Canada T6G 2G2
| | - Ramin Dastanpour
- Department of Mechanical Engineering, University of British Columbia , Vancouver, British Columbia Canada V6T 1Z4
| | - Steven N Rogak
- Department of Mechanical Engineering, University of British Columbia , Vancouver, British Columbia Canada V6T 1Z4
| | - Wolfgang Jäger
- Department of Chemistry, University of Alberta , Edmonton, Alberta Canada T6G 2G2
| | - Jason S Olfert
- Department of Mechanical Engineering, University of Alberta , Edmonton, Alberta, Canada T6G 2G8
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35
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Ji D, Li L, Pang B, Xue P, Wang L, Wu Y, Zhang H, Wang Y. Characterization of black carbon in an urban-rural fringe area of Beijing. ENVIRONMENTAL POLLUTION (BARKING, ESSEX : 1987) 2017; 223:524-534. [PMID: 28139325 DOI: 10.1016/j.envpol.2017.01.055] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/20/2016] [Revised: 01/17/2017] [Accepted: 01/18/2017] [Indexed: 06/06/2023]
Abstract
Measuring black carbon (BC) is critical to understand the impact of combustion aerosols on air quality and climate change. In this study, BC was measured in 2014 at a unique community formed with rapid economic development and urbanization in an urban-rural fringe area of Beijing. Hourly BC concentrations were 0.1-33.5 μg/m3 with the annual average of 4.4 ± 3.7 μg/m3. BC concentrations had clear diurnal, weekly, and seasonal variations, and were closely related with atmospheric visibility. The absorption coefficient of aerosols increased while its contribution to extinction coefficient decreased with the enhancement of PM2.5 concentration. The high mass absorption efficiency (MAE) of EC was attributed to a combination of coal combustion, vehicular emission and rapidly coating by water-soluble ions and organic carbon (OC). BC concentrations followed a typical lognormal pattern, with over 88% samples in 0.1-10.0 μg/m3. Low BC levels were mostly bounded up with winds from north and northwest. Coal combustion and biomass burning were closely associated with severe haze pollution events. Firework discharge had significant UV absorption contribution. During the Asia-Pacific Economic Cooperation (APEC) forum in November 2014, air quality obviously improved due to various control strategies.
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Affiliation(s)
- Dongsheng Ji
- State Key Laboratory of Atmospheric Boundary Layer Physics and Atmospheric Chemistry, Institute of Atmospheric Physics, Chinese Academy of Sciences, Beijing, China.
| | - Liang Li
- China National Environmental Monitoring Center, Beijing, China
| | - Bo Pang
- State Key Laboratory of Atmospheric Boundary Layer Physics and Atmospheric Chemistry, Institute of Atmospheric Physics, Chinese Academy of Sciences, Beijing, China; Collaboration Innovation Center on Forecast and Evaluation of Meteorological Disasters, Key Laboratory for Aerosol-Cloud-Precipitation of China Meteorological Administration, Nanjing University of Information Science and Technology, Nanjing, China
| | - Peng Xue
- State Key Laboratory of Atmospheric Boundary Layer Physics and Atmospheric Chemistry, Institute of Atmospheric Physics, Chinese Academy of Sciences, Beijing, China; Collaboration Innovation Center on Forecast and Evaluation of Meteorological Disasters, Key Laboratory for Aerosol-Cloud-Precipitation of China Meteorological Administration, Nanjing University of Information Science and Technology, Nanjing, China
| | - Lili Wang
- State Key Laboratory of Atmospheric Boundary Layer Physics and Atmospheric Chemistry, Institute of Atmospheric Physics, Chinese Academy of Sciences, Beijing, China
| | - Yunfei Wu
- State Key Laboratory of Atmospheric Boundary Layer Physics and Atmospheric Chemistry, Institute of Atmospheric Physics, Chinese Academy of Sciences, Beijing, China
| | - Hongliang Zhang
- Department of Civil & Environmental Engineering, Louisiana State University, Baton Rouge, LA, USA.
| | - Yuesi Wang
- State Key Laboratory of Atmospheric Boundary Layer Physics and Atmospheric Chemistry, Institute of Atmospheric Physics, Chinese Academy of Sciences, Beijing, China
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36
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Woods E, Hull AW, Tigue ML. Uptake of Pyrene onto Fatty Acid Coated NaCl Aerosol Particles. J Phys Chem A 2016; 120:10160-10168. [PMID: 27991789 DOI: 10.1021/acs.jpca.6b11023] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Photoelectric charging experiments monitor the uptake of pyrene onto NaCl aerosol particles coated with either oleic acid or myristic acid. In both cases, thin coatings produce a small net decrease in pyrene uptake. In the larger coverage limit, the uptake of the myristic acid coated particles remains nearly constant whereas the oleic acid coated particles exhibit greater uptake rates than the bare NaCl particles. Fitting the results with a multilayer kinetic model yields uptake rate coefficients as well as parameters that describe the distribution of organic molecules on the aerosol particle surface. The model accounts for the decrease in uptake associated with thin coatings of oleic acid through a concomitant reduction in surface area. The adsorption rate constants for the myristic and oleic acid coated surfaces are 50 and 80 times faster, respectively, than for NaCl. The desorption rates for pyrene on the fatty acid surfaces are faster, as well. For myristic acid coatings, the fast desorption (over 400 times the rate of desorption from NaCl) results in slower net adsorption, whereas for oleic acid (approximately 12 times the desorption rate from NaCl), the net uptake rate increases with coverage. The results also suggest that both myristic acid and oleic acid spread incompletely on the aerosol surfaces under the conditions of these experiments. In the optimized kinetic model, the fatty acids cover approximately 50% of the surface when the nominal coating thickness is approximately 6 nm. The surface is over 90% covered with a nominal coating thickness of 20 nm, which is approximately 10% of particle diameter in these experiments. Very thin oleic acid coatings reduce the surface area of particles consistent with the preferential coverage of highly corrugated or porous regions.
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Affiliation(s)
- Ephraim Woods
- Department of Chemistry, Colgate University , Hamilton, New York 13346, United States
| | - Alexander W Hull
- Department of Chemistry, Colgate University , Hamilton, New York 13346, United States
| | - Megan L Tigue
- Department of Chemistry, Colgate University , Hamilton, New York 13346, United States
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37
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Kupiszewski P, Zanatta M, Mertes S, Vochezer P, Lloyd G, Schneider J, Schenk L, Schnaiter M, Baltensperger U, Weingartner E, Gysel M. Ice residual properties in mixed-phase clouds at the high-alpine Jungfraujoch site. JOURNAL OF GEOPHYSICAL RESEARCH. ATMOSPHERES : JGR 2016; 121:12343-12362. [PMID: 28066694 PMCID: PMC5175215 DOI: 10.1002/2016jd024894] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/03/2016] [Revised: 08/30/2016] [Accepted: 09/20/2016] [Indexed: 05/28/2023]
Abstract
Ice residual (IR) and total aerosol properties were measured in mixed-phase clouds (MPCs) at the high-alpine Jungfraujoch research station. Black carbon (BC) content and coating thickness of BC-containing particles were determined using single-particle soot photometers. The ice activated fraction (IAF), derived from a comparison of IR and total aerosol particle size distributions, showed an enrichment of large particles in the IR, with an increase in the IAF from values on the order of 10-4 to 10-3 for 100 nm (diameter) particles to 0.2 to 0.3 for 1 μm (diameter) particles. Nonetheless, due to the high number fraction of submicrometer particles with respect to total particle number, IR size distributions were still dominated by the submicrometer aerosol. A comparison of simultaneously measured number size distributions of BC-free and BC-containing IR and total aerosol particles showed depletion of BC by number in the IR, suggesting that BC does not play a significant role in ice nucleation in MPCs at the Jungfraujoch. The potential anthropogenic climate impact of BC via the glaciation effect in MPCs is therefore likely to be negligible at this site and in environments with similar meteorological conditions and a similar aerosol population. The IAF of the BC-containing particles also increased with total particle size, in a similar manner as for the BC-free particles, but on a level 1 order of magnitude lower. Furthermore, BC-containing IR were found to have a thicker coating than the BC-containing total aerosol, suggesting the importance of atmospheric aging for ice nucleation.
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Affiliation(s)
- Piotr Kupiszewski
- Laboratory of Atmospheric ChemistryPaul Scherrer InstituteVilligenSwitzerland
- Now at Department of MeteorologyStockholm UniversityStockholmSweden
| | - Marco Zanatta
- Laboratory of Atmospheric ChemistryPaul Scherrer InstituteVilligenSwitzerland
- Laboratoire de Glaciologie et Géophysique de l'EnvironnementUniversité Grenoble Alpes/CNRSGrenobleFrance
- Now at Alfred Wegener InstituteHelmholtz Centre for Polar and Marine ResearchBremerhavenGermany
| | - Stephan Mertes
- Leibniz Institute for Tropospheric ResearchLeipzigGermany
| | - Paul Vochezer
- Institute of Meteorology and Climate ResearchKarlsruhe Institute of TechnologyKarlsruheGermany
| | - Gary Lloyd
- Centre for Atmospheric Science, SEAESUniversity of ManchesterManchesterUK
| | - Johannes Schneider
- Particle Chemistry DepartmentMax Planck Institute for ChemistryMainzGermany
| | - Ludwig Schenk
- Leibniz Institute for Tropospheric ResearchLeipzigGermany
| | - Martin Schnaiter
- Institute of Meteorology and Climate ResearchKarlsruhe Institute of TechnologyKarlsruheGermany
| | - Urs Baltensperger
- Laboratory of Atmospheric ChemistryPaul Scherrer InstituteVilligenSwitzerland
| | - Ernest Weingartner
- Laboratory of Atmospheric ChemistryPaul Scherrer InstituteVilligenSwitzerland
- Now at Institute for Aerosol and Sensor TechnologyUniversity of Applied SciencesWindischSwitzerland
| | - Martin Gysel
- Laboratory of Atmospheric ChemistryPaul Scherrer InstituteVilligenSwitzerland
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38
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Lead chromate detected as a source of atmospheric Pb and Cr (VI) pollution. Sci Rep 2016; 6:36088. [PMID: 27779222 PMCID: PMC5078766 DOI: 10.1038/srep36088] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2016] [Accepted: 10/10/2016] [Indexed: 11/08/2022] Open
Abstract
Spherical black carbon aggregates were frequently observed in dust dry deposition in Daejeon, Korea. They were tens of micrometers in diameter and presented a mixture of black carbon and several mineral phases. Transmission electron microscopy (TEM) observations with energy-dispersive X-ray spectroscopy (EDS) and selected area diffraction pattern (SADP) analyses confirmed that the aggregates were compact and included significant amounts of lead chromate (PbCrO4). The compositions and morphologies of the nanosized lead chromate particles suggest that they probably originated from traffic paint used in roads and were combined as discrete minerals with black carbon. Based on Pb isotope analysis and air-mass backward trajectories, the dust in Daejeon received a considerable input of anthropogenic pollutants from heavily industrialized Chinese cities, which implies that long-range transported aerosols containing PbCrO4 were a possible source of the lead and hexavalent chromium levels in East Asia. Lead chromate should be considered to be a source of global atmospheric Pb and Cr(VI) pollution, especially given its toxicity.
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39
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Fierce L, Bond TC, Bauer SE, Mena F, Riemer N. Black carbon absorption at the global scale is affected by particle-scale diversity in composition. Nat Commun 2016; 7:12361. [PMID: 27580627 PMCID: PMC5025768 DOI: 10.1038/ncomms12361] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2015] [Accepted: 06/24/2016] [Indexed: 11/22/2022] Open
Abstract
Atmospheric black carbon (BC) exerts a strong, but uncertain, warming effect on the climate. BC that is coated with non-absorbing material absorbs more strongly than the same amount of BC in an uncoated particle, but the magnitude of this absorption enhancement (Eabs) is not well constrained. Modelling studies and laboratory measurements have found stronger absorption enhancement than has been observed in the atmosphere. Here, using a particle-resolved aerosol model to simulate diverse BC populations, we show that absorption is overestimated by as much as a factor of two if diversity is neglected and population-averaged composition is assumed across all BC-containing particles. If, instead, composition diversity is resolved, we find Eabs=1−1.5 at low relative humidity, consistent with ambient observations. This study offers not only an explanation for the discrepancy between modelled and observed absorption enhancement, but also demonstrates how particle-scale simulations can be used to develop relationships for global-scale models. Model and laboratory experiments disagree with observations regarding the absorption properties of black carbon particles. Here, using a particle-resolved aerosol model, the authors show that when composition diversity is considered, absorption enhancement is consistent with ambient observations.
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Affiliation(s)
- Laura Fierce
- Department of Environmental and Climate Sciences , Brookhaven National Laboratory, Upton, New York 11973, USA.,Visiting Scientists Program, University Corporation for Atmospheric Research, Boulder, Colorado 80307, USA
| | - Tami C Bond
- Department of Civil and Environmental Engineering, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, USA
| | - Susanne E Bauer
- NASA Goddard Institute for Space Studies, New York City, New York 10025, USA.,The Earth Institute, Columbia University, New York City, New York 10025, USA
| | - Francisco Mena
- Department of Civil and Environmental Engineering, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, USA
| | - Nicole Riemer
- Department of Atmospheric Sciences, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, USA
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40
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Guo S, Hu M, Lin Y, Gomez-Hernandez M, Zamora ML, Peng J, Collins DR, Zhang R. OH-Initiated Oxidation of m-Xylene on Black Carbon Aging. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2016; 50:8605-8612. [PMID: 27384756 DOI: 10.1021/acs.est.6b01272] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
Laboratory experiments are conducted to investigate aging of size-classified black carbon (BC) particles from OH-initiated oxidation of m-xylene. The variations in the particle size, mass, effective density, morphology, optical properties, hygroscopicity, and activation as cloud condensation nuclei (CCN) are simultaneously measured by a suite of aerosol instruments, when BC particles are exposed to the oxidation products of the OH-m-xylene reactions. The BC aging is governed by the coating thickness (Δrve), which is correlated to the reaction time and initial concentrations of m-xylene and NOx. For an initial diameter of 100 nm and Δrve = 44 nm, the particle size and mass increase by a factor of 1.5 and 10.4, respectively, and the effective density increases from 0.43 to 1.45 g cm(-3) due to organic coating and collapsing of the BC core. The BC particles are fully converted from a highly fractal to nearly spherical morphology for Δrve = 30 nm. The scattering, absorption, and single scattering albedo of BC particles are enhanced accordingly with organic coating. The critical supersaturation for CCN activation is reduced to 0.1% with Δrve = 44 nm. The results imply that the oxidation of m-xylene exhibits larger impacts in modifying the BC particle properties than those for the OH-initiated oxidation of isoprene and toluene.
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Affiliation(s)
- Song Guo
- State Key Joint Laboratory of Environmental Simulation and Pollution Control, College of Environmental Sciences and Engineering, Peking University , Beijing, 100871, China
| | - Min Hu
- State Key Joint Laboratory of Environmental Simulation and Pollution Control, College of Environmental Sciences and Engineering, Peking University , Beijing, 100871, China
| | - Yun Lin
- Department of Atmospheric Sciences, Texas A&M University , College Station, Texas 77843, United States
| | - Mario Gomez-Hernandez
- Department of Chemistry, Texas A&M University , College Station, Texas 77843, United States
| | - Misti L Zamora
- Department of Atmospheric Sciences, Texas A&M University , College Station, Texas 77843, United States
| | - Jianfei Peng
- State Key Joint Laboratory of Environmental Simulation and Pollution Control, College of Environmental Sciences and Engineering, Peking University , Beijing, 100871, China
| | - Donald R Collins
- Department of Atmospheric Sciences, Texas A&M University , College Station, Texas 77843, United States
| | - Renyi Zhang
- State Key Joint Laboratory of Environmental Simulation and Pollution Control, College of Environmental Sciences and Engineering, Peking University , Beijing, 100871, China
- Department of Atmospheric Sciences, Texas A&M University , College Station, Texas 77843, United States
- Department of Chemistry, Texas A&M University , College Station, Texas 77843, United States
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41
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You R, Radney JG, Zachariah MR, Zangmeister CD. Measured Wavelength-Dependent Absorption Enhancement of Internally Mixed Black Carbon with Absorbing and Nonabsorbing Materials. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2016; 50:7982-90. [PMID: 27359341 PMCID: PMC5501421 DOI: 10.1021/acs.est.6b01473] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/15/2023]
Abstract
Optical absorption spectra of laboratory generated aerosols consisting of black carbon (BC) internally mixed with nonabsorbing materials (ammonium sulfate, AS, and sodium chloride, NaCl) and BC with a weakly absorbing brown carbon surrogate derived from humic acid (HA) were measured across the visible to near-IR (550 to 840 nm). Spectra were measured in situ using a photoacoustic spectrometer and step-scanning a supercontinuum laser source with a tunable wavelength and bandwidth filter. BC had a mass-specific absorption cross section (MAC) of 7.89 ± 0.25 m(2) g(-1) at λ = 550 nm and an absorption Ångström exponent (AAE) of 1.03 ± 0.09 (2σ). For internally mixed BC, the ratio of BC mass to the total mass of the mixture was chosen as 0.13 to mimic particles observed in the terrestrial atmosphere. The manner in which BC mixed with each material was determined from transmission electron microscopy (TEM). AS/BC and HA/BC particles were fully internally mixed, and the BC was both internally and externally mixed for NaCl/BC particles. The AS/BC, NaCl/BC, and HA/BC particles had AAEs of 1.43 ± 0.05, 1.34 ± 0.06, and 1.91 ± 0.05, respectively. The observed absorption enhancement of mixed BC relative to the pure BC was wavelength dependent for AS/BC and decreased from 1.5 at λ = 550 nm with increasing wavelength while the NaCl/BC enhancement was essentially wavelength independent. For HA/BC, the enhancement ranged from 2 to 3 and was strongly wavelength dependent. Removal of the HA absorption contribution to enhancement revealed that the enhancement was ≈1.5 and independent of wavelength.
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Affiliation(s)
- Rian You
- Material Measurement Laboratory, National Institute of Standards and Technology, Gaithersburg, Maryland 20899
- Department of Chemistry and Biochemistry, University of Maryland, College Park, Maryland 20742
| | - James G. Radney
- Material Measurement Laboratory, National Institute of Standards and Technology, Gaithersburg, Maryland 20899
| | - Michael R. Zachariah
- Material Measurement Laboratory, National Institute of Standards and Technology, Gaithersburg, Maryland 20899
- Department of Chemistry and Biochemistry, University of Maryland, College Park, Maryland 20742
| | - Christopher D. Zangmeister
- Material Measurement Laboratory, National Institute of Standards and Technology, Gaithersburg, Maryland 20899
- Corresponding Author: . Phone: (301)975-8709. Fax: (301)975-3670
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42
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Markedly enhanced absorption and direct radiative forcing of black carbon under polluted urban environments. Proc Natl Acad Sci U S A 2016; 113:4266-71. [PMID: 27035993 DOI: 10.1073/pnas.1602310113] [Citation(s) in RCA: 149] [Impact Index Per Article: 18.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Black carbon (BC) exerts profound impacts on air quality and climate because of its high absorption cross-section over a broad range of electromagnetic spectra, but the current results on absorption enhancement of BC particles during atmospheric aging remain conflicting. Here, we quantified the aging and variation in the optical properties of BC particles under ambient conditions in Beijing, China, and Houston, United States, using a novel environmental chamber approach. BC aging exhibits two distinct stages, i.e., initial transformation from a fractal to spherical morphology with little absorption variation and subsequent growth of fully compact particles with a large absorption enhancement. The timescales to achieve complete morphology modification and an absorption amplification factor of 2.4 for BC particles are estimated to be 2.3 h and 4.6 h, respectively, in Beijing, compared with 9 h and 18 h, respectively, in Houston. Our findings indicate that BC under polluted urban environments could play an essential role in pollution development and contribute importantly to large positive radiative forcing. The variation in direct radiative forcing is dependent on the rate and timescale of BC aging, with a clear distinction between urban cities in developed and developing countries, i.e., a higher climatic impact in more polluted environments. We suggest that mediation in BC emissions achieves a cobenefit in simultaneously controlling air pollution and protecting climate, especially for developing countries.
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43
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Liu S, Aiken AC, Gorkowski K, Dubey MK, Cappa CD, Williams LR, Herndon SC, Massoli P, Fortner EC, Chhabra PS, Brooks WA, Onasch TB, Jayne JT, Worsnop DR, China S, Sharma N, Mazzoleni C, Xu L, Ng NL, Liu D, Allan JD, Lee JD, Fleming ZL, Mohr C, Zotter P, Szidat S, Prévôt ASH. Enhanced light absorption by mixed source black and brown carbon particles in UK winter. Nat Commun 2015; 6:8435. [PMID: 26419204 PMCID: PMC4598716 DOI: 10.1038/ncomms9435] [Citation(s) in RCA: 86] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2015] [Accepted: 08/21/2015] [Indexed: 11/09/2022] Open
Abstract
Black carbon (BC) and light-absorbing organic carbon (brown carbon, BrC) play key roles in warming the atmosphere, but the magnitude of their effects remains highly uncertain. Theoretical modelling and laboratory experiments demonstrate that coatings on BC can enhance BC's light absorption, therefore many climate models simply assume enhanced BC absorption by a factor of ∼1.5. However, recent field observations show negligible absorption enhancement, implying models may overestimate BC's warming. Here we report direct evidence of substantial field-measured BC absorption enhancement, with the magnitude strongly depending on BC coating amount. Increases in BC coating result from a combination of changing sources and photochemical aging processes. When the influence of BrC is accounted for, observationally constrained model calculations of the BC absorption enhancement can be reconciled with the observations. We conclude that the influence of coatings on BC absorption should be treated as a source and regionally specific parameter in climate models.
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Affiliation(s)
- Shang Liu
- Earth and Environmental Sciences Division, Los Alamos National Laboratory, Los Alamos, New Mexico 87545, USA.,Cooperative Institute for Research in the Environmental Sciences and Department of Chemistry and Biochemistry, University of Colorado, Boulder, Colorado 80309, USA
| | - Allison C Aiken
- Earth and Environmental Sciences Division, Los Alamos National Laboratory, Los Alamos, New Mexico 87545, USA
| | - Kyle Gorkowski
- Earth and Environmental Sciences Division, Los Alamos National Laboratory, Los Alamos, New Mexico 87545, USA.,Department of Civil and Environmental Engineering, Carnegie Mellon University, Pittsburgh, Pennsylvania 15213, USA
| | - Manvendra K Dubey
- Earth and Environmental Sciences Division, Los Alamos National Laboratory, Los Alamos, New Mexico 87545, USA
| | - Christopher D Cappa
- Department of Civil and Environmental Engineering, University of California, Davis, California 95616, USA
| | | | | | - Paola Massoli
- Aerodyne Research, Inc. Billerica, Massachusetts 01821, USA
| | | | - Puneet S Chhabra
- Aerodyne Research, Inc. Billerica, Massachusetts 01821, USA.,Department of Chemical Engineering, University of Texas at Austin, Austin, Texas 78712, USA
| | | | - Timothy B Onasch
- Aerodyne Research, Inc. Billerica, Massachusetts 01821, USA.,Department of Chemistry, Boston College, Boston, Massachusetts 02467, USA
| | - John T Jayne
- Aerodyne Research, Inc. Billerica, Massachusetts 01821, USA
| | | | - Swarup China
- Physics Department and Atmospheric Sciences Program, Michigan Technological University, Houghton, Michigan 49931, USA
| | - Noopur Sharma
- Physics Department and Atmospheric Sciences Program, Michigan Technological University, Houghton, Michigan 49931, USA
| | - Claudio Mazzoleni
- Physics Department and Atmospheric Sciences Program, Michigan Technological University, Houghton, Michigan 49931, USA
| | - Lu Xu
- School of Chemical and Biomolecular Engineering, Georgia Institute of Technology, Atlanta, Georgia 30332, USA
| | - Nga L Ng
- School of Chemical and Biomolecular Engineering, Georgia Institute of Technology, Atlanta, Georgia 30332, USA.,School of Earth and Atmospheric Sciences, Georgia Institute of Technology, Atlanta, Georgia 30332, USA
| | - Dantong Liu
- School of Earth, Atmospheric and Environmental Science, University of Manchester, Manchester M13 9PL, UK
| | - James D Allan
- School of Earth, Atmospheric and Environmental Science, University of Manchester, Manchester M13 9PL, UK.,National Centre for Atmospheric Science, University of Manchester, Manchester M13 9PL, UK
| | - James D Lee
- Wolfson Atmospheric Chemistry Laboratory and National Centre for Atmospheric Science, University of York, York YO10 5DD, UK
| | - Zoë L Fleming
- National Centre for Atmospheric Science, Department of Chemistry, University of Leicester, Leicester LE1 7RH, UK
| | - Claudia Mohr
- Department of Atmospheric Sciences, University of Washington, Seattle, Washington 98195, USA.,Institute for Meteorology and Climate Research, Karlsruhe Institute of Technology, Eggenstein-Leopoldshafen 76344, Germany
| | - Peter Zotter
- Laboratory of Atmospheric Chemistry, Paul Scherrer Institute, Villigen 5232, Switzerland.,Lucerne School of Engineering and Architecture, Bioenergy Research, Lucerne University of Applied Sciences and Arts, Horw 6048, Switzerland
| | - Sönke Szidat
- Department of Chemistry and Biochemistry and Oeschger Centre for Climate Change Research, University of Bern, Bern 3012, Switzerland
| | - André S H Prévôt
- Laboratory of Atmospheric Chemistry, Paul Scherrer Institute, Villigen 5232, Switzerland
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44
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Cheng T, Wu Y, Gu X, Chen H. Effects of mixing states on the multiple-scattering properties of soot aerosols. OPTICS EXPRESS 2015; 23:10808-10821. [PMID: 25969118 DOI: 10.1364/oe.23.010808] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
The radiative properties of soot aerosols are highly sensitive to the mixing states of black carbon particles and other aerosol components. Light absorption properties are enhanced by the mixing state of soot aerosols. Quantification of the effects of mixing states on the scattering properties of soot aerosol are still not completely resolved, especially for multiple-scattering properties. This study focuses on the effects of the mixing state on the multiple scattering of soot aerosols using the vector radiative transfer model. Two types of soot aerosols with different mixing states such as external mixture soot aerosols and internal mixture soot aerosols are studied. Upward radiance/polarization and hemispheric flux are studied with variable soot aerosol loadings for clear and haze scenarios. Our study showed dramatic changes in upward radiance/polarization due to the effects of the mixing state on the multiple scattering of soot aerosols. The relative difference in upward radiance due to the different mixing states can reach 16%, whereas the relative difference of upward polarization can reach 200%. The effects of the mixing state on the multiple-scattering properties of soot aerosols increase with increasing soot aerosol loading. The effects of the soot aerosol mixing state on upwelling hemispheric flux are much smaller than in upward radiance/polarization, which increase with increasing solar zenith angle. The relative difference in upwelling hemispheric flux due to the different soot aerosol mixing states can reach 18% when the solar zenith angle is 75°. The findings should improve our understanding of the effects of mixing states on the optical properties of soot aerosols and their effects on climate. The mixing mechanism of soot aerosols is of critical importance in evaluating the climate effects of soot aerosols, which should be explicitly included in radiative forcing models and aerosol remote sensing.
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45
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Moise T, Flores JM, Rudich Y. Optical Properties of Secondary Organic Aerosols and Their Changes by Chemical Processes. Chem Rev 2015; 115:4400-39. [DOI: 10.1021/cr5005259] [Citation(s) in RCA: 242] [Impact Index Per Article: 26.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Affiliation(s)
- Tamar Moise
- Department of Earth and Planetary
Sciences, Weizmann Institute, Rehovot 76100, Israel
| | - J. Michel Flores
- Department of Earth and Planetary
Sciences, Weizmann Institute, Rehovot 76100, Israel
| | - Yinon Rudich
- Department of Earth and Planetary
Sciences, Weizmann Institute, Rehovot 76100, Israel
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46
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Pöschl U, Shiraiwa M. Multiphase chemistry at the atmosphere-biosphere interface influencing climate and public health in the anthropocene. Chem Rev 2015; 115:4440-75. [PMID: 25856774 DOI: 10.1021/cr500487s] [Citation(s) in RCA: 232] [Impact Index Per Article: 25.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Affiliation(s)
- Ulrich Pöschl
- Multiphase Chemistry Department, Max Planck Institute for Chemistry, 55128 Mainz, Germany
| | - Manabu Shiraiwa
- Multiphase Chemistry Department, Max Planck Institute for Chemistry, 55128 Mainz, Germany
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47
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Schnitzler EG, Dutt A, Charbonneau AM, Olfert JS, Jäger W. Soot aggregate restructuring due to coatings of secondary organic aerosol derived from aromatic precursors. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2014; 48:14309-14316. [PMID: 25390075 DOI: 10.1021/es503699b] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
Restructuring of monodisperse soot aggregates due to coatings of secondary organic aerosol (SOA) derived from hydroxyl radical-initiated oxidation of toluene, p-xylene, ethylbenzene, and benzene was investigated in a series of photo-oxidation (smog) chamber experiments. Soot aggregates were generated by combustion of ethylene using a McKenna burner, treated by denuding, size-selected by a differential mobility analyzer, and injected into a smog chamber, where they were exposed to low vapor pressure products of aromatic hydrocarbon oxidation, which formed SOA coatings. Aggregate restructuring began once a threshold coating mass was reached, and the degree of the subsequent restructuring increased with mass growth factor. Although significantly compacted, fully processed aggregates were not spherical, with a mass-mobility exponent of 2.78, so additional SOA was required to fill indentations between collapsed branches of the restructured aggregates before the dynamic shape factor of coated particles approached 1. Trends in diameter growth factor, effective density, and dynamic shape factor with increasing mass growth factor indicate distinct stages in soot aggregate processing by SOA coatings. The final degree and coating mass dependence of soot restructuring were found to be the same for SOA coatings from all four aromatic precursors, indicating that the surface tensions of the SOA coatings are similar.
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Affiliation(s)
- Elijah G Schnitzler
- Department of Chemistry, University of Alberta , Edmonton, Alberta T6G 2G2, Canada
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48
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Cheng T, Wu Y, Chen H. Effects of morphology on the radiative properties of internally mixed light absorbing carbon aerosols with different aging status. OPTICS EXPRESS 2014; 22:15904-15917. [PMID: 24977845 DOI: 10.1364/oe.22.015904] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
Light absorbing carbon aerosols play a substantial role in climate change through radiative forcing, which is the dominant absorber of solar radiation. Radiative properties of light absorbing carbon aerosols are strongly dependent on the morphological factors and the mixing mechanism of black carbon with other aerosol components. This study focuses on the morphological effects on the optical properties of internally mixed light absorbing carbon aerosols using the numerically exact superposition T-matrix method. Three types aerosols with different aging status such as freshly emitted BC particles, thinly coated light absorbing carbon aerosols, heavily coated light absorbing carbon aerosols are studied. Our study showed that morphological factors change with the aging of internally mixed light absorbing carbon aerosols to result in a dramatic change in their optical properties. The absorption properties of light absorbing carbon aerosols can be enhanced approximately a factor of 2 at 0.67 um, and these enhancements depend on the morphological factors. A larger shell/core diameter ratio of volume-equivalent shell-core spheres (S/C), which indicates the degree of coating, leads to stronger absorption. The enhancement of absorption properties accompanies a greater enhancement of scattering properties, which is reflected in an increase in single scattering albedo (SSA). The enhancement of single scattering albedo due to the morphological effects can reach a factor of 3.75 at 0.67 μm. The asymmetry parameter has a similar yet smaller enhancement. Moreover, the corresponding optical properties of shell-and-core model determined by using Lorenz -Mie solutions are presented for comparison. We found that the optical properties of internally mixed light absorbing carbon aerosol can differ fundamentally from those calculated for the Mie theory shell-and-core model, particularly for thinly coated light absorbing carbon aerosols. Our studies indicate that the complex morphology of internally mixed light absorbing carbon aerosols must be explicitly considered in climate radiation balance.
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49
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Wang Q, Schwarz JP, Cao J, Gao R, Fahey DW, Hu T, Huang RJ, Han Y, Shen Z. Black carbon aerosol characterization in a remote area of Qinghai-Tibetan Plateau, western China. THE SCIENCE OF THE TOTAL ENVIRONMENT 2014; 479-480:151-158. [PMID: 24561294 DOI: 10.1016/j.scitotenv.2014.01.098] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/30/2013] [Revised: 01/24/2014] [Accepted: 01/25/2014] [Indexed: 06/03/2023]
Abstract
The concentrations, size distributions, and mixing states of refractory black carbon (rBC) aerosols were measured with a ground-based Single Particle Soot Photometer (SP2), and aerosol absorption was measured with an Aethalometer at Qinghai Lake (QHL), a rural area in the Northeastern Tibetan Plateau of China in October 2011. The area was not pristine, with an average rBC mass concentration of 0.36 μg STP-m(-3) during the two-week campaign period. The rBC concentration peaked at night and reached the minimal in the afternoon. This diurnal cycle of concentration is negatively correlated with the mixed layer depth and ventilation. When air masses from the west of QHL were sampled in late afternoon to early evening, the average rBC concentration of 0.21 μg STP-m(-3) was observed, representing the rBC level in a larger Tibetan Plateau region because of the highest mixed layer depth. A lognormal primary mode with mass median diameter (MMD) of ~175 nm, and a small secondary lognormal mode with MMD of 470-500 nm of rBC were observed. Relative reduction in the secondary mode during a snow event supports recent work that suggested size dependent removal of rBC by precipitation. About 50% of the observed rBC cores were identified as thickly coated by non-BC material. A comparison of the Aethalometer and SP2 measurements suggests that non-BC species significantly affect the Aethalometer measurements in this region. A scaling factor for the Aethalometer data at a wavelength of 880 nm is therefore calculated based on the measurements, which may be used to correct other Aethalometer datasets collected in this region for a more accurate estimate of the rBC loading. The results present here significantly improve our understanding of the characteristics of rBC aerosol in the less studied Tibetan Plateau region and further highlight the size dependent removal of BC via precipitation.
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Affiliation(s)
- Qiyuan Wang
- Key Laboratory of Aerosol Science & Technology, SKLLQG, Institute of Earth Environment, Chinese Academy of Sciences, Xi'an 710075, China; Department of Environmental Science and Engineering, Xi'an Jiaotong University, Xi'an 710049, China
| | - J P Schwarz
- National Oceanic and Atmospheric Administration, Earth System Research Laboratory, NOAA, Boulder, CO, USA; Cooperative Institute for Research in Environmental Sciences, University of Colorado, Boulder, CO, USA
| | - Junji Cao
- Key Laboratory of Aerosol Science & Technology, SKLLQG, Institute of Earth Environment, Chinese Academy of Sciences, Xi'an 710075, China; Institute of Global Environmental Change, Xi'an Jiaotong University, Xi'an 710049, China.
| | - Rushan Gao
- National Oceanic and Atmospheric Administration, Earth System Research Laboratory, NOAA, Boulder, CO, USA
| | - D W Fahey
- National Oceanic and Atmospheric Administration, Earth System Research Laboratory, NOAA, Boulder, CO, USA; Cooperative Institute for Research in Environmental Sciences, University of Colorado, Boulder, CO, USA
| | - Tafeng Hu
- Key Laboratory of Aerosol Science & Technology, SKLLQG, Institute of Earth Environment, Chinese Academy of Sciences, Xi'an 710075, China
| | - R-J Huang
- Laboratory of Atmospheric Chemistry, Paul Scherrer Institute, 5232 Villigen PSI, Switzerland; Centre for Climate and Air Pollution Studies, Ryan Institute, National University of Ireland Galway, University Road, Galway, Ireland
| | - Yongming Han
- Key Laboratory of Aerosol Science & Technology, SKLLQG, Institute of Earth Environment, Chinese Academy of Sciences, Xi'an 710075, China
| | - Zhenxing Shen
- Department of Environmental Science and Engineering, Xi'an Jiaotong University, Xi'an 710049, China
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50
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Lack DA, Moosmüller H, McMeeking GR, Chakrabarty RK, Baumgardner D. Characterizing elemental, equivalent black, and refractory black carbon aerosol particles: a review of techniques, their limitations and uncertainties. Anal Bioanal Chem 2014; 406:99-122. [PMID: 24297322 PMCID: PMC3877426 DOI: 10.1007/s00216-013-7402-3] [Citation(s) in RCA: 49] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2013] [Revised: 09/18/2013] [Accepted: 09/25/2013] [Indexed: 12/05/2022]
Abstract
Elemental-, equivalent black- and refractory black-carbon are terms that have been defined in order to dissect the more general term, black carbon, into its component parts related to its specific chemical and optical properties and its impact on climate and health. Recent publications have attempted to clarify the meaning of these terms with respect to their environmental impact, particularly on climate. Here, we focus on the measurement aspects, reviewing the most commonly implemented techniques for the direct and indirect derivation of black carbon properties, their strengths, limitations, and uncertainties, and provide a non-exhaustive bibliography where the reader can find more detailed information. This review paper is designed as a guide for those wishing to learn about the current state of black carbon measurement instrumentation, how calibration is carried out, when one instrument may have the advantage over another, and where new techniques are needed to fill important knowledge gaps.
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Affiliation(s)
- Daniel A. Lack
- NOAA Earth System Research Laboratory, 325 Broadway, Boulder, CO 80305-3337 USA
- Cooperative Institute for Research in Environmental Sciences, University of Colorado, Boulder, CO 80309 USA
| | | | - Gavin R. McMeeking
- Droplet Measurement Technologies, 2545 Central Avenue, Boulder, CO 80301 USA
| | | | - Darrel Baumgardner
- Droplet Measurement Technologies, 2545 Central Avenue, Boulder, CO 80301 USA
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