Investigation of organic aerosol sources using fractionated water-soluble organic carbon measured at an urban site

2012 ◽  
Vol 55 ◽  
pp. 64-72 ◽  
Author(s):  
Seung Shik Park ◽  
Sung Yong Cho ◽  
Kyung-Won Kim ◽  
Kwon-Ho Lee ◽  
Kweon Jung
Keyword(s):  
Organic Carbon ◽  
Organic Aerosol ◽  
Water Soluble ◽  
Urban Site ◽  
Water Soluble Organic Carbon ◽  
Soluble Organic Carbon ◽  
Aerosol Sources

scholarly journals Mass absorption efficiency of elemental carbon and water-soluble organic carbon in Beijing, China

2011 ◽  
Vol 11 (22) ◽  
pp. 11497-11510 ◽  
Author(s):  
Y. Cheng ◽  
K.-B. He ◽  
M. Zheng ◽  
F.-K. Duan ◽  
Z.-Y. Du ◽  
...  
Keyword(s):  
Organic Carbon ◽  
Biomass Burning ◽  
Light Absorption ◽  
Elemental Carbon ◽  
Organic Aerosol ◽  
Absorption Efficiency ◽  
Water Soluble ◽  
Water Soluble Organic Carbon ◽  
Soluble Organic Carbon ◽  
Mass Absorption Efficiency

Abstract. The mass absorption efficiency (MAE) of elemental carbon (EC) in Beijing was quantified using a thermal-optical carbon analyzer. The MAE measured at 632 nm was 8.45±1.71 and 9.41±1.92 m2 g−1 during winter and summer respectively. The daily variation of MAE was found to coincide with the abundance of organic carbon (OC), especially the OC to EC ratio, perhaps due to the enhancement by coating with organic aerosol (especially secondary organic aerosol, SOA) or the artifacts resulting from the redistribution of liquid-like organic particles during the filter-based absorption measurements. Using a converting approach that accounts for the discrepancy caused by measurements methods of both light absorption and EC concentration, previously published MAE values were converted to the equivalent-MAE, which is the estimated value if using the same measurement methods as used in this study. The equivalent-MAE was found to be much lower in the regions heavily impacted by biomass burning (e.g., below 2.7 m2 g−1 for two Indian cities). Results from source samples (including diesel exhaust samples and biomass smoke samples) also demonstrated that emissions from biomass burning would decrease the MAE of EC. Moreover, optical properties of water-soluble organic carbon (WSOC) in Beijing were 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 MAE of WSOC (measured at 365 nm) was 1.79±0.24 and 0.71±0.20 m2 g−1 during winter and summer respectively. The large discrepancy between the MAE of WSOC during winter and summer was attributed to the difference in the precursors of SOA such that anthropogenic volatile organic compounds (AVOCs) should be more important as the precursors of SOA in winter. The MAE 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 stronger emissions of biomass burning in China.

scholarly journals Functional characterization of the water-soluble organic carbon of size-fractionated aerosol in the southern Mississippi Valley

2014 ◽  
Vol 14 (12) ◽  
pp. 6075-6088 ◽  
Author(s):  
M.-C. G. Chalbot ◽  
J. Brown ◽  
P. Chitranshi ◽  
G. Gamboa da Costa ◽  
E. D. Pollock ◽  
...  
Keyword(s):  
Organic Carbon ◽  
1H Nmr ◽  
Biomass Burning ◽  
Organic Aerosol ◽  
Water Soluble ◽  
Particle Mass ◽  
Proton Nuclear Magnetic Resonance ◽  
Relative Distribution ◽  
Water Soluble Organic Carbon ◽  
Soluble Organic Carbon

Abstract. The chemical content of water-soluble organic carbon (WSOC) as a function of particle size was characterized in Little Rock, Arkansas in winter and spring 2013. The objectives of this study were to (i) compare the functional characteristics of coarse, fine and ultrafine WSOC and (ii) reconcile the sources of WSOC for periods when carbonaceous aerosol was the most abundant particulate component. The WSOC accounted for 5% of particle mass for particles with dp > 0.96 μm and 10% of particle mass for particles with dp < 0.96 μm. Non-exchangeable aliphatic (H–C), unsaturated aliphatic (H–C–C=), oxygenated saturated aliphatic (H–C–O), acetalic (O–CH–O) and aromatic (Ar–H) protons were determined by proton nuclear magnetic resonance (1H-NMR). The total non-exchangeable organic hydrogen concentrations varied from 4.1 ± 0.1 nmol m−3 for particles with 1.5 < dp < 3.0 μm to 73.9 ± 12.3 nmol m−3 for particles with dp < 0.49 μm. The molar H / C ratios varied from 0.48 ± 0.05 to 0.92 ± 0.09, which were comparable to those observed for combustion-related organic aerosol. The R–H was the most abundant group, representing about 45% of measured total non-exchangeable organic hydrogen concentrations, followed by H–C–O (27%) and H–C–C= (26%). Levoglucosan, amines, ammonium and methanesulfonate were identified in NMR fingerprints of fine particles. Sucrose, fructose, glucose, formate and acetate were associated with coarse particles. These qualitative differences of 1H-NMR profiles for different particle sizes indicated the possible contribution of biological aerosols and a mixture of aliphatic and oxygenated compounds from biomass burning and traffic exhausts. The concurrent presence of ammonium and amines also suggested the presence of ammonium/aminium nitrate and sulfate secondary aerosol. The size-dependent origin of WSOC was further corroborated by the increasing δ13C abundance from −26.81 ± 0.18‰ for the smallest particles to −25.93 ± 0.31‰ for the largest particles and the relative distribution of the functional groups as compared to those previously observed for marine, biomass burning and secondary organic aerosol. The latter also allowed for the differentiation of urban combustion-related aerosol and biological particles. The five types of organic hydrogen accounted for the majority of WSOC for particles with dp > 3.0 μm and dp < 0.96 μm.

scholarly journals Spatial and seasonal variations of fine particle water-soluble organic carbon (WSOC) over the Southeastern United States: implications for secondary organic aerosol formation

2012 ◽  
Vol 12 (4) ◽  
pp. 9621-9664 ◽  
Author(s):  
X. Zhang ◽  
Z. Liu ◽  
A. Hecobian ◽  
M. Zheng ◽  
N. H. Frank ◽  
...  
Keyword(s):  
Organic Carbon ◽  
Fine Particles ◽  
Secondary Organic Aerosol ◽  
Organic Aerosol ◽  
Water Soluble ◽  
Aerosol Formation ◽  
Southeastern Us ◽  
Urban Rural ◽  
Water Soluble Organic Carbon ◽  
Soluble Organic Carbon

Abstract. Secondary organic aerosol (SOA) in the Southeastern US is investigated by analyzing the spatial-temporal distribution of water-soluble organic carbon (WSOC) and other PM2.5 components from 900 archived 24 h Teflon filters collected at 15 urban or rural EPA Federal Reference Method (FRM) network sites throughout 2007. Online measurements of WSOC at an urban/rural-paired site in Georgia in the summer of 2008 are contrasted to the filter data. Based on FRM filters, excluding biomass-burning events (levoglucosan < 50 ng m−3), WSOC and sulfate were highly correlated with PM2.5 mass and both comprised a large mass fraction of PM2.5 (13% and 35%, respectively). Sulfate and WSOC both tracked ambient temperature throughout the year, suggesting the temperature effects were mainly on the photochemical processes that lead to secondary formation. FRM WSOC, and to a lesser extent sulfate, were spatially homogeneous throughout the region, yet WSOC was moderately enhanced (27%) in locations of greater predicted isoprene emissions in summer. A Positive Matrix Factorization (PMF) analysis identified two major source types for the summer WSOC; 22% of the WSOC were associated with ammonium sulfate, and 56% of the WSOC was associated with brown carbon and oxalate. A small urban excess of FRM WSOC (10%) was observed in the summer of 2007, however, comparisons of online WSOC measurements at one urban/rural pair (Atlanta/Yorkville) in August 2008 showed substantially greater difference in WSOC (31%) relative to the FRM data, suggesting a low bias for urban filters. The measured Atlanta urban excess, combined with the estimated boundary layer heights, gave an estimated Atlanta daily WSOC production rate in August of 0.55 mg C m−2 h−1 between mid-morning and mid-afternoon. This study characterizes the regional nature of fine particles in the Southeastern US, confirming the importance of secondary organic aerosol and the roles of both biogenic and anthropogenic emissions.

scholarly journals A method for on-line measurement of water-soluble organic carbon in ambient aerosol particles: Results from an urban site

2004 ◽  
Vol 31 (13) ◽  
pp. n/a-n/a ◽  
Author(s):  
A. P. Sullivan ◽  
R. J. Weber ◽  
A. L. Clements ◽  
J. R. Turner ◽  
M. S. Bae ◽  
...  
Keyword(s):  
Organic Carbon ◽  
Aerosol Particles ◽  
Water Soluble ◽  
Urban Site ◽  
Ambient Aerosol ◽  
Line Measurement ◽  
Water Soluble Organic Carbon ◽  
Soluble Organic Carbon ◽  
On Line

scholarly journals Nuclear Magnetic Resonance Characterization of Water Soluble Organic Carbon of Atmospheric Aerosol Types

2019 ◽  
Vol 14 (5) ◽  
pp. 1934578X1984997 ◽  
Author(s):  
Marie-Cecile G. Chalbot ◽  
Ilias G. Kavouras
Keyword(s):  
Nuclear Magnetic Resonance ◽  
Magnetic Resonance ◽  
Organic Carbon ◽  
Atmospheric Aerosol ◽  
Road Dust ◽  
Water Soluble ◽  
Natural Soil ◽  
Water Soluble Organic Carbon ◽  
Soluble Organic Carbon ◽  
Aerosol Sources

The water soluble organic carbon of the prevalent atmospheric aerosol sources (traffic exhausts, paved road dust, agricultural soil, native soil, wood combustion, epicuticular waxes from pine and broad-leaved trees, and pollen) has been characterized using 1H (1-dimensional), 1H-1H-correlation spectroscopy and 1H-13C-heteronuclear single quantum correlation 2-dimensional (2D) nuclear magnetic resonance (NMR) spectroscopy. Traffic exhaust particles were mainly constituted of primary alcohols, carbohydrates, functionalized olefins, C3 and C4 oxy- and hydroxyl-carboxylic acids, and short-chain alkanes. Road dust was a mixture of soil particles and traffic components. Agricultural, natural, road dust, and traffic particles contained broad signals that were attributed to poly-carboxylic compounds typically found in humic compounds and humic-like substances. Traces of traffic particles (ie, peaks in the 7.3-7.5 ppm [phthalic acid derivatives] and signals found in the 0.5-3 ppm originating from functionalized carboxylic acids) were also found in natural soil dust. Long-chain (>C3) fatty acids and amino acids were found in road dust, natural soil, pine trees waxes, pollen, and woodburning. The aromatic region mainly constituted of lignin derivatives and cellulose/hemicellulose pyrolysis products (signals in 2D-NMR) in woodburning. Primary biogenic and woodburning particles were uniquely clustered as compared to traffic exhausts, road, agricultural, and natural dust based on the relative ratio of hydro-oxygenated functional groups (H-C-O and H-C-C=O) to the sum of aliphatics. Overall, source-specific NMR spectrometric fingerprints, functional composition profiles, and several organic compounds were identified allowing for the reconciliation of ambient organic aerosol sources including the degree of atmospheric aging.

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