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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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Li X, Xiao M, Xu X, Zhou J, Yang K, Wang Z, Zhang W, Hopke PK, Zhao W. Light Absorption Properties of Organic Aerosol from Wood Pyrolysis: Measurement Method Comparison and Radiative Implications. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2020; 54:7156-7164. [PMID: 32437142 DOI: 10.1021/acs.est.0c01475] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
Growing evidence indicates that organic aerosol (OA) is a significant absorber of solar radiation. Such absorptive OA is known as "brown carbon" (BrC). However, a formal analytical method for BrC is currently lacking although several methods have been applied to determine its absorption properties. Reported imaginary refractive index (kOA) values from various combustion sources span 2 orders of magnitude. Measurement methods are an important factor affecting this kOA variation. In this work, isolated OA from wood pyrolysis was used to compare four methods to determine absorbing properties of OA. The generated aerosol was lognormally distributed, spherical, and nearly pure organic matter. Optical closure was considered as the reference method. kOA calculated from the extract bulk light absorbance measurement was comparable to that determined by optical closure. kOA and mass absorption cross section obtained by online and offline filter-based transmission measurements were similar, but 3.5 to 5.0 times greater than those determined by optical closure. Absorption Ångström Exponents determined by the four methods were comparable and ranged from 6.1 to 6.8. A clear-sky radiative transfer model implied that using the optical parameters derived from different methods in the full climate model could produce different radiative impacts of primary OA emissions.
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Affiliation(s)
- Xinghua Li
- School of Space and Environment, Beihang University, Beijing 100191, P. R. China
| | - Maodong Xiao
- School of Space and Environment, Beihang University, Beijing 100191, P. R. China
| | - Xuezhe Xu
- Laboratory of Atmospheric Physico-Chemistry, Anhui Institute of Optics and Fine Mechanics, Chinese Academy of Sciences, Hefei 230031, Anhui, P. R. China
| | - Jiacheng Zhou
- Laboratory of Atmospheric Physico-Chemistry, Anhui Institute of Optics and Fine Mechanics, Chinese Academy of Sciences, Hefei 230031, Anhui, P. R. China
| | - Kaiqiang Yang
- School of Space and Environment, Beihang University, Beijing 100191, P. R. China
| | - Zihao Wang
- School of Space and Environment, Beihang University, Beijing 100191, P. R. China
| | - Weijun Zhang
- Laboratory of Atmospheric Physico-Chemistry, Anhui Institute of Optics and Fine Mechanics, Chinese Academy of Sciences, Hefei 230031, Anhui, P. R. China
| | - Philip K Hopke
- Department of Public Health Sciences, University of Rochester School of Medicine and Dentistry, Rochester, New York 14642, United States
- Center for Air Resources Engineering and Science, Clarkson University, Potsdam, New York 13699, United States
| | - Weixiong Zhao
- Laboratory of Atmospheric Physico-Chemistry, Anhui Institute of Optics and Fine Mechanics, Chinese Academy of Sciences, Hefei 230031, Anhui, P. R. China
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Improving the Estimation of Daily Aerosol Optical Depth and Aerosol Radiative Effect Using an Optimized Artificial Neural Network. REMOTE SENSING 2018. [DOI: 10.3390/rs10071022] [Citation(s) in RCA: 40] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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Rajput P, Sarin MM. Polar and non-polar organic aerosols from large-scale agricultural-waste burning emissions in Northern India: Implications to organic mass-to-organic carbon ratio. CHEMOSPHERE 2014; 103:74-79. [PMID: 24331033 DOI: 10.1016/j.chemosphere.2013.11.028] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/02/2013] [Revised: 11/06/2013] [Accepted: 11/11/2013] [Indexed: 06/03/2023]
Abstract
This study focuses on characteristics of organic aerosols (polar and non-polar) and total organic mass-to-organic carbon ratio (OM/OC) from post-harvest agricultural-waste (paddy- and wheat-residue) burning emissions in Northern India. Aerosol samples from an upwind location (Patiala: 30.2°N, 76.3°E) in the Indo-Gangetic Plain were analyzed for non-polar and polar fractions of organic carbon (OC1 and OC2) and their respective mass (OM1 and OM2). On average, polar organic aerosols (OM2) contribute nearly 85% of the total organic mass (OM) from the paddy- and wheat-residue burning emissions. The water-soluble-OC (WSOC) to OC2 ratio, within the analytical uncertainty, is close to 1 from both paddy- and wheat-residue burning emissions. However, temporal variability and relatively low WSOC/OC2 ratio (Av: 0.67±0.06) is attributed to high moisture content and poor combustion efficiency during paddy-residue burning, indicating significant contribution (∼30%) of aromatic carbon to OC2. The OM/OC ratio for non-polar (OM1/OC1∼1.2) and polar organic aerosols (OM2/OC2∼2.2), hitherto unknown for open agricultural-waste burning emissions, is documented in this study. The total OM/OC ratio is nearly identical, 1.9±0.2 and 1.8±0.2, from paddy- and wheat-residue burning emissions.
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Affiliation(s)
| | - M M Sarin
- Physical Research Laboratory, Ahmedabad 380 009, India.
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Rajput P, Sarin MM, Sharma D, Singh D. Organic aerosols and inorganic species from post-harvest agricultural-waste burning emissions over northern India: impact on mass absorption efficiency of elemental carbon. ENVIRONMENTAL SCIENCE. PROCESSES & IMPACTS 2014; 16:2371-9. [PMID: 25124269 DOI: 10.1039/c4em00307a] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/08/2023]
Abstract
Atmospheric PM2.5 (particulate matter with aerodynamic diameter of ≤ 2.5 μm), collected from a source region [Patiala: 30.2 °N; 76.3 °E; 250 m above mean sea level] of emissions from post-harvest agricultural-waste (paddy-residue) burning in the Indo-Gangetic Plain (IGP), North India, has been studied for its chemical composition and impact on regional atmospheric radiative forcing. On average, organic aerosol mass accounts for 63% of PM2.5, whereas the contribution of elemental carbon (EC) is ∼3.5%. Sulphate, nitrate and ammonium contribute up to ∼85% of the total water-soluble inorganic species (WSIS), which constitutes ∼23% of PM2.5. The potassium-to-organic carbon ratio from paddy-residue burning emissions (KBB(+)/OC: 0.05 ± 0.01) is quite similar to that reported from Amazonian and Savanna forest-fires; whereas non-sea-salt-sulphate-to-OC ratio (nss-SO4(2-)/OC: 0.21) and nss-SO4(2-)/EC ratio of 2.6 are significantly higher (by factor of 5 to 8). The mass absorption efficiency of EC (3.8 ± 1.3 m(2) g(-1)) shows significant decrease with a parallel increase in the concentrations of organic aerosols and scattering species (sulphate and nitrate). A cross plot of OC/EC and nss-SO4(2-)/EC ratios show distinct differences for post-harvest burning emissions from paddy-residue as compared to those from fossil-fuel combustion sources in south-east Asia.
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Affiliation(s)
- Prashant Rajput
- Geosciences Division, Physical Research Laboratory, Navrangpura, Ahmedabad 380 009, Gujarat, India.
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Liu P, Zhang Y, Martin ST. Complex refractive indices of thin films of secondary organic materials by spectroscopic ellipsometry from 220 to 1200 nm. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2013; 47:13594-13601. [PMID: 24191734 DOI: 10.1021/es403411e] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
The complex refractive indices of three different types of secondary organic material (SOM) were obtained for 220 to 1200 nm using a variable angle spectroscopic ellipsometer. Aerosol particles were produced in a flow tube reactor by ozonolysis of volatile organic compounds, including the monoterpenes α-pinene and limonene and the aromatic catechol (benzene-1,2-diol). Optically reflective thin films of SOM were grown by electrostatic precipitation of the aerosol particles onto silicon substrates. The ellipsometry analysis showed that both the real and imaginary components of the refractive indices decreased with increasing wavelength. The real part n(λ) could be parametrized by the three-term form of Cauchy's equation, as follows: n(λ) = B + C/λ(2) + D/λ(4) where λ is the wavelength and B, C, and D are fitting parameters. The real refractive indices of the three SOMs ranged from 1.53 to 1.58, 1.49-1.52, and 1.48-1.50 at 310, 550, and 1000 nm, respectively. The catechol-derived SOM absorbed light in the ultraviolet (UV) range. By comparison, the UV absorption of the monoterpene-derived SOMs was negligible. On the basis of the measured refractive indices, optical properties were modeled for a typical atmospheric particle population. The results suggest that the wavelength dependence of the refractive indices can vary the Angstrom exponent by up to 0.1 across the range 310 to 550 nm. The modeled single-scattering albedo can likewise vary from 0.97 to 0.85 at 310 nm (UV-B). Variability in the optical properties of different types of SOMs can imply important differences in the relative effects of atmospheric particles on tropospheric photochemistry, as well as possible inaccuracies in some satellite-retrieved properties such as optical depth and mode diameter.
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Affiliation(s)
- Pengfei Liu
- School of Engineering and Applied Sciences, Harvard University , Cambridge, Massachusetts 02138, United States
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Ocko IB, Ramaswamy V, Ginoux P, Ming Y, Horowitz LW. Sensitivity of scattering and absorbing aerosol direct radiative forcing to physical climate factors. ACTA ACUST UNITED AC 2012. [DOI: 10.1029/2012jd018019] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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Ganguly D, Rasch PJ, Wang H, Yoon JH. Climate response of the South Asian monsoon system to anthropogenic aerosols. ACTA ACUST UNITED AC 2012. [DOI: 10.1029/2012jd017508] [Citation(s) in RCA: 153] [Impact Index Per Article: 12.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
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Fry MM, Naik V, West JJ, Schwarzkopf MD, Fiore AM, Collins WJ, Dentener FJ, Shindell DT, Atherton C, Bergmann D, Duncan BN, Hess P, MacKenzie IA, Marmer E, Schultz MG, Szopa S, Wild O, Zeng G. The influence of ozone precursor emissions from four world regions on tropospheric composition and radiative climate forcing. ACTA ACUST UNITED AC 2012. [DOI: 10.1029/2011jd017134] [Citation(s) in RCA: 79] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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Li W, Shao L. Mixing and water-soluble characteristics of particulate organic compounds in individual urban aerosol particles. ACTA ACUST UNITED AC 2010. [DOI: 10.1029/2009jd012575] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
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Ganguly D, Ginoux P, Ramaswamy V, Dubovik O, Welton J, Reid EA, Holben BN. Inferring the composition and concentration of aerosols by combining AERONET and MPLNET data: Comparison with other measurements and utilization to evaluate GCM output. ACTA ACUST UNITED AC 2009. [DOI: 10.1029/2009jd011895] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
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Ginoux P, Horowitz LW, Ramaswamy V, Geogdzhayev IV, Holben BN, Stenchikov G, Tie X. Evaluation of aerosol distribution and optical depth in the Geophysical Fluid Dynamics Laboratory coupled model CM2.1 for present climate. ACTA ACUST UNITED AC 2006. [DOI: 10.1029/2005jd006707] [Citation(s) in RCA: 64] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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