scholarly journals Significant Seasonal Change in Optical Properties by atmospheric humic-like substances (HULIS) in Water-Soluble Organic Carbon Aerosols

2017 ◽  
Author(s):  
Heejun Han ◽  
Guebuem Kim
Keyword(s):  
Optical Properties ◽  
Organic Carbon ◽  
Uv Radiation ◽  
Dominant Role ◽  
Critical Role ◽  
Organic Aerosols ◽  
Water Soluble ◽  
Photochemical Degradation ◽  
Water Soluble Organic Carbon ◽  
Soluble Organic Carbon

Abstract. Atmospheric humic-like substance (HULIS) is an important fraction of water-soluble organic carbon (WSOC) accounting for the light-absorbing properties of organic aerosols. HULIS is responsible for light-absorbing properties of organic aerosols in the atmosphere. Although various sources of HULIS have been studied extensively, its sinks are poorly constrained. In this study, we found seasonal changes in the optical and chemical characteristics of HULIS and WSOC, which are decreased by approximately 80 % and 30 %, respectively, from the cold season (Oct–Jan) to the warm season (Jun–Sep) due to enhanced solar ultraviolet (UV) radiation. The dominant role of photochemical degradation on light-absorbing organic aerosols, as a sink of HULIS, was further confirmed based on a laboratory experiment by evaluating impact of UV radiation on the optical properties of HULIS and WSOC contents. Our results suggest that seasonal variation of HULIS in WSOC is resulted mainly by photo-induced degradation in the atmosphere. Thus, photochemical degradation of HULIS seems to play a critical role on seasonal variations in the light-absorbing properties of organic aerosols as well as the biogeochemical impact of WSOC on Earth’s surface.

scholarly journals Water-soluble organic carbon aerosols during a full New Delhi winter: Isotope-based source apportionment and optical properties

2014 ◽  
Vol 119 (6) ◽  
pp. 3476-3485 ◽  
Author(s):  
Elena N. Kirillova ◽  
August Andersson ◽  
Suresh Tiwari ◽  
Atul Kumar Srivastava ◽  
Deewan Singh Bisht ◽  
...  
Keyword(s):  
Optical Properties ◽  
Organic Carbon ◽  
Source Apportionment ◽  
Water Soluble ◽  
New Delhi ◽  
Water Soluble Organic Carbon ◽  
Soluble Organic Carbon ◽  
Carbon Aerosols

scholarly journals Estimation of Source-Based Aerosol Optical Properties for Polydisperse Aerosols from Receptor Models

2019 ◽  
Vol 9 (7) ◽  
pp. 1443 ◽  
Author(s):  
Chang Jung ◽  
Ji Lee ◽  
Junshik Um ◽  
Seoung Lee ◽  
Young Yoon ◽  
...  
Keyword(s):  
Optical Properties ◽  
Organic Carbon ◽  
Mass Concentration ◽  
Water Soluble ◽  
Aerosol Size Distribution ◽  
Receptor Model ◽  
Aerosol Optical Properties ◽  
Extinction Coefficients ◽  
Water Soluble Organic Carbon ◽  
Soluble Organic Carbon

We estimated source-based aerosol optical properties for polydisperse aerosols according to a chemical-species-resolved mass contribution method based on source apportionment. We investigated the sensitivity of aerosol optical properties based on PM2.5 (particulate matter that have a diameter of less than 2.5 micrometers) monitoring results. These aerosols were composed of ions, metals, elemental carbon, and water-soluble organic carbon which includes humic-like carbon substances and water-soluble organic carbon. We calculated aerosols’ extinction coefficients based on the PM2.5 composition data and the results of a multivariate receptor model (Solver for Mixture Problem model, SMP). Based on the mass concentration of chemical composition and nine sources calculated with the SMP receptor model, we estimated the size-resolved mass extinction efficiencies for each aerosol source using a multilinear regression model. Consequently, this study quantitatively determined the size resolved sources contributing to the apportionment-based aerosol optical properties and calculated their respective contributions. The results show that source-resolved mass concentrations and extinction coefficients had varying contributions. This discrepancy between the source-based mass concentration and extinction coefficient was mainly due to differences between the source-dependent aerosol size distribution and the aerosol optical properties from different sources.

scholarly journals Investigating the evolution of water-soluble organic carbon in evaporating cloud water

2021 ◽  
Author(s):  
Vikram Pratap ◽  
Amy E. Christiansen ◽  
Annmarie G. Carlton ◽  
Sara Lance ◽  
Paul Casson ◽  
...  
Keyword(s):  
Optical Properties ◽  
Organic Carbon ◽  
Cloud Water ◽  
Atmospheric Particles ◽  
Water Soluble ◽  
Secondary Aerosol ◽  
Aerosol Mass ◽  
Water Soluble Organic Carbon ◽  
Soluble Organic Carbon

Cloud cycling plays a key role in the evolution of atmospheric particles and gases, producing secondary aerosol mass and transforming the optical properties and impacts of aerosols globally.

scholarly journals Organic Molecular Tracers in PM2.5 at Urban Sites during Spring and Summer in Japan: Impact of Secondary Organic Aerosols on Water-Soluble Organic Carbon

Atmosphere ◽  
2021 ◽  
Vol 12 (5) ◽  
pp. 579
Author(s):  
Fumikazu Ikemori ◽  
Rie Nishimura ◽  
Shinji Saito ◽  
Masayuki Akiyama ◽  
Shigekazu Yamamoto ◽  
...  
Keyword(s):  
Organic Carbon ◽  
Urban Areas ◽  
Secondary Organic Aerosols ◽  
Organic Aerosols ◽  
Water Soluble ◽  
Gas Chromatography Mass Spectrometry ◽  
Water Soluble Organic Carbon ◽  
Soluble Organic Carbon ◽  
Molecular Tracers ◽  
Urban Sites

To understand the characteristics of secondary organic aerosols (SOAs) and estimate their impact on water-soluble organic carbon (WSOC) in urban areas in Japan, we measured 17 organic tracers using gas chromatography–mass spectrometry from particulate matter with an aerodynamic diameter smaller than 2.5 μm collected at five urban sites in Japan during spring and summer. Most anthropogenic, monoterpene-derived, and isoprene-derived SOA tracers showed meaningful correlations with potential ozone in both these seasons. These results indicate that oxidants play an important role in SOAs produced during both seasons in urban cities in Japan. WSOC was significantly affected by anthropogenic and monoterpene-derived SOAs during spring and three SOA groups during summer at most of the sites sampled. The total estimated secondary organic carbons (SOCs), including mono-aromatic, di-aromatic, monoterpene-derived, and isoprene-derived SOCs, could explain the WSOC fractions of 39–63% in spring and 46–54% in summer at each site. Notably, monoterpene-derived and mono-aromatic SOCs accounted for most of the total estimated SOCs in both spring (85–93%) and summer (75–82%) at each site. These results indicate that SOAs significantly impact WSOC concentrations during both these seasons at urban sites in Japan.

scholarly journals Optical properties of elemental carbon and water-soluble organic carbon in Beijing, China

2011 ◽  
Vol 11 (2) ◽  
pp. 6221-6258
Author(s):  
Y. Cheng ◽  
K.-B. He ◽  
M. Zheng ◽  
F.-K. Duan ◽  
Y.-L. Ma ◽  
...  
Keyword(s):  
Optical Properties ◽  
Organic Carbon ◽  
Biomass Burning ◽  
Light Absorption ◽  
Elemental Carbon ◽  
Water Soluble ◽  
Brown Carbon ◽  
Sulphate Concentration ◽  
Water Soluble Organic Carbon ◽  
Soluble Organic Carbon

Abstract. The mass absorption cross-section (MAC) of elemental carbon (EC) in Beijing was quantified using a thermal-optical carbon analyzer and the influences of mixing state and sources of carbonaceous aerosol were investigated. The MAC measured at 632 nm was 29.0 and 32.0 m2 g−1 during winter and summer respectively. MAC correlated well with the organic carbon (OC) to EC ratio (R2 = 0.91) which includes important information about the extent of secondary organic aerosol (SOA) production, indicating the enhancement of MAC by coating with SOA. The extrapolated MAC value was 10.5 m2 g−1 when the OC to EC ratio is zero, which was 5.6 m2 g−1 after correction by the enhancement factor (1.87) caused by the artifacts associated with the "filter-based" methods. The MAC also increased with sulphate (R2 = 0.84) when the sulphate concentration was below 10 μg m−3, whereas MAC and sulphate were only weekly related when the sulphate concentration was above 10 μg m−3, indicating the MAC of EC was also enhanced by coating with sulphate. Based on a converting approach that accounts for the discrepancy caused by measurements methods of both light absorption and EC concentration, previously published MAC values were converted to the "equivalent MAC", which is the estimated value if using the same measurement methods as used in this study. The "equivalent MAC" was found to be much lower in the regions heavily impacted by biomass burning (e.g., India), probably due to the influence of brown carbon. Optical properties of water-soluble organic carbon (WSOC) in Beijing were also presented. Light absorption by WSOC exhibited strong wavelength (λ) dependence such that absorption varied approximately as λ−7, which was characteristic of the brown carbon spectra. The mass absorption efficiency (σabs) of WSOC (measured at 365 nm) was 1.83 and 0.70 m2 g−1 during winter and summer respectively. The seasonal pattern of σabs was attributed to the difference in the precursors of SOA, because WSOC in Beijing has been demonstrated to be strongly linked to SOA. Moreover, the σabs of WSOC in Beijing was much higher than results from the southeastern United States which were obtained using the same method as used in this study, perhaps due to the influence of biomass burning.

scholarly journals Measurement report: Molecular composition, optical properties, and radiative effects of water-soluble organic carbon in snowpack samples from northern Xinjiang, China

2021 ◽  
Vol 21 (11) ◽  
pp. 8531-8555
Author(s):  
Yue Zhou ◽  
Christopher P. West ◽  
Anusha P. S. Hettiyadura ◽  
Xiaoying Niu ◽  
Hui Wen ◽  
...  
Keyword(s):  
Optical Properties ◽  
Organic Carbon ◽  
Radiative Forcing ◽  
Molecular Level ◽  
Bulk Composition ◽  
Water Soluble ◽  
Northern Xinjiang ◽  
Water Soluble Organic Carbon ◽  
Soluble Organic Carbon

Abstract. Water-soluble organic carbon (WSOC) in the cryosphere has an important impact on the biogeochemistry cycling and snow–ice surface energy balance through changes in the surface albedo. This work reports on the chemical characterization of WSOC in 28 representative snowpack samples collected across a regional area of northern Xinjiang, northwestern China. We employed multimodal analytical chemistry techniques to investigate both bulk and molecular-level composition of WSOC and its optical properties, informing the follow-up radiative forcing (RF) modeling estimates. Based on the geographic differences and proximity of emission sources, the snowpack collection sites were grouped as urban/industrial (U), rural/remote (R), and soil-influenced (S) sites, for which average WSOC total mass loadings were measured as 1968 ± 953 ng g−1 (U), 885 ± 328 ng g−1 (R), and 2082 ± 1438 ng g−1 (S), respectively. The S sites showed the higher mass absorption coefficients at 365 nm (MAC365) of 0.94 ± 0.31 m2 g−1 compared to those of U and R sites (0.39 ± 0.11 m2 g−1 and 0.38 ± 0.12 m2 g−1, respectively). Bulk composition of WSOC in the snowpack samples and its basic source apportionment was inferred from the excitation–emission matrices and the parallel factor analysis featuring relative contributions of one protein-like (PRLIS) and two humic-like (HULIS-1 and HULIS-2) components with ratios specific to each of the S, U, and R sites. Additionally, a sample from site 120 showed unique pollutant concentrations and spectroscopic features remarkably different from all other U, R, and S samples. Molecular-level characterization of WSOC using high-resolution mass spectrometry (HRMS) provided further insights into chemical differences among four types of samples (U, R, S, and 120). Specifically, many reduced-sulfur-containing species with high degrees of unsaturation and aromaticity were uniquely identified in U samples, suggesting an anthropogenic source. Aliphatic/protein-like species showed the highest contribution in R samples, indicating their biogenic origin. The WSOC components from S samples showed high oxygenation and saturation levels. A few unique CHON and CHONS compounds with high unsaturation degree and molecular weight were detected in the 120 sample, which might be anthraquinone derivatives from plant debris. Modeling of the WSOC-induced RF values showed warming effects of 0.04 to 0.59 W m−2 among different groups of sites, which contribute up to 16 % of that caused by black carbon (BC), demonstrating the important influences of WSOC on the snow energy budget.

scholarly journals Seasonal variations of concentrations and optical properties of water soluble HULIS collected in urban environments

2010 ◽  
Vol 10 (9) ◽  
pp. 4085-4095 ◽  
Author(s):  
C. Baduel ◽  
D. Voisin ◽  
J.-L. Jaffrezo
Keyword(s):  
Optical Properties ◽  
Organic Carbon ◽  
Uv Spectroscopy ◽  
Organic Aerosol ◽  
Urban Environments ◽  
Water Soluble ◽  
Aerosol Mass ◽  
Water Soluble Organic Carbon ◽  
Soluble Organic Carbon ◽  
Specific Absorbance

Abstract. Major contributors to the organic aerosol include water-soluble macromolecular compounds (e.g. HULISWS: Water Soluble Humic LIke Substances). The nature and sources of HULISWS are still largely unknown. This work is based on a monitoring in six different French cities performed during summer and winter seasons. HULISWS analysis was performed with a selective method of extraction complemented by carbon quantification. UV spectroscopy was also applied for their chemical characterisation. HULISWS carbon represent an important contribution to the organic aerosol mass in summer and winter, as it accounts for 12–22% of Organic Carbon and 34–40% of Water Soluble Organic Carbon. We found strong differences in the optical properties (specific absorbance at 250, 272, 280 nm and E2/E3 ratio) and therefore in the chemical structure between HULISWS from samples of summer- and wintertime. These differences highlight different processes responsible for emissions and formation of HULISWS according to the season, namely biomass burning in winter, and secondary processes in summer. Specific absorbance can also be considered as a rapid and useful indicator of the origin of HULISWS in urban environment.

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