Seasonal variations of water-soluble organic carbon, dicarboxylic acids, ketocarboxylic acids, and α-dicarbonyls in Central Himalayan aerosols

Hegde, Prashant; Kawamura, Kimitaka

doi:10.5194/acp-12-6645-2012

Cited by 83 publications

(61 citation statements)

References 90 publications

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“…Concentrations of phthalic (Ph) acid (mean: 13 ng m −3 ), a tracer for vehicle emissions (Kawamura and Ikushima, 1993) are about 2 folds lower than that from Chennai (mean: 21 ng m −3 ) and 7 folds lower than that from Hong Kong (mean: 84 ng m −3 ). We found that concentration of tPh acid in PM 2.5 is similar to that reported from Sapporo (mean: 2.6 ng m −3 , Aggarwal and Kawamura, 2008) but is lower than those from Chennai (mean: 52 ng m −3 , Pavuruli et al, 2010) and Nainital (mean: 4.3 ng m −3 , Hegde and Kawamura, 2012). tPh could be produced from open burning of solid waste (plastic) (Simoneit et al, 2005;Kawamura and Pavuluri, 2010), which occurs commonly in Tanzania.…”

Section: Comparison Of Molecular Composition Of Diacids and Related Csupporting

confidence: 63%

“…Based on the filed experiments, aqueous aerosol phase production of oxalic acid was reported in urban and suburban sites (Miyazaki et al, 2009;He and Kawamura, 2010). However, when compared to literature values, our C 3 /C 4 ratios are slightly lower than those (1.5) reported in Tokyo (Kawamura and Ikushima, 1993) and 1.4 in Chennai but comparable to those (0.84) in Nainital, India (Hegde and Kawamura, 2012) and those (1.3) in Jeju Island in the East China Sea .…”

Section: Comparison Of Molecular Composition Of Diacids and Related Ccontrasting

confidence: 53%

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Molecular composition of dicarboxylic acids, ketocarboxylic acids, α-dicarbonyls and fatty acids in atmospheric aerosols from Tanzania, East Africa during wet and dry seasons

Mkoma

Kawamura

2013

Atmos. Chem. Phys.

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Atmospheric aerosol samples of PM2.5 and PM10 were collected during the wet and dry seasons in 2011 from a rural site in Tanzania and analysed for water-soluble dicarboxylic acids, ketocarboxylic acids, α-dicarbonyls, and fatty acids using a gas chromatography/flame ionization detector (GC/FID) and GC/mass spectrometry. Here we report the molecular composition and sources of diacids and related compounds for wet and dry seasons. Oxalic acid (C2) was found as the most abundant diacid species followed by succinic and/or malonic acids whereas glyoxylic acid and glyoxal were the dominant ketoacid and α-dicarbonyl, respectively in both seasons in PM2.5 and PM10. Mean concentration of C2 in PM2.5 (121 ± 47 ng m−3) was lower in wet season than dry season (258 ± 69 ng m−3). Similarly, PM10 samples showed lower concentration of C2 (169 ± 42 ng m−3) in wet season than dry season (292 ± 165 ng m−3). Relative abundances of C2 in total diacids were 65% and 67% in PM2.5 and 65% and 64% in PM10 in the wet and dry seasons, respectively. Total concentrations of diacids (289–362 ng m−3), ketoacids (37.8–53.7 ng m−3), and α-dicarbonyls (5.7–7.8 ng m−3) in Tanzania are higher than those reported at a rural background site in Nylsvley (South Africa) but comparable or lower than those reported from sites in Asia and Europe. Diacids and ketoacids were found to be present mainly in PM2.5 in both seasons (total α-dicarbonyls in the dry season), suggesting a production of organic acids from pyrogenic sources and photochemical oxidations. Averaged contributions of total diacids to aerosol total carbon were 1.4% in PM2.5 and 2.1% in PM10 during wet season and 3.3% in PM2.5 and 3.9% in PM10 during dry season whereas those to water-soluble organic carbon were 2.2% and 4.7% in PM2.5 during wet season and 3.1% and 5.8% in PM10 during dry season. The higher ratios in dry season suggest an enhanced photochemical oxidation of organic precursors probably via heterogeneous reactions on aerosols under strong solar radiation. Strong positive correlations were found among diacids and related compounds as well as good relations to source tracers in both seasons, suggesting a mixed source from natural biogenic emissions, biomass burning, biofuel combustion, and photochemical production

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Section: Comparison Of Molecular Composition Of Diacids and Related Csupporting

confidence: 63%

Section: Comparison Of Molecular Composition Of Diacids and Related Ccontrasting

confidence: 53%

Molecular composition of dicarboxylic acids, ketocarboxylic acids, α-dicarbonyls and fatty acids in atmospheric aerosols from Tanzania, East Africa during wet and dry seasons

Mkoma

Kawamura

2013

Atmos. Chem. Phys.

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“…Glyoxylic acid (ωC 2 ) is an intermediate compound to produce oxalic acid (C 2 ) (Kawamura et al, 1996a;Warneck, 2003;Lim et al, 2005;Hegde and Kawamura, 2012;Wang et al, 2012). Thus, ωC 2 / C 2 ratios can serve as a tracer to evaluate the oxidation process of organic aerosols.…”

Section: Compositional Changes Of Dicarboxylic Acidsmentioning

confidence: 99%

High abundances of water-soluble dicarboxylic acids, ketocarboxylic acids and α-dicarbonyls in the mountaintop aerosols over the North China Plain during wheat burning season

et al. 2013

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Aerosol (TSP) samples were collected at the summit of Mount Tai (elevation: 1534 m a.s.l., 36.25° N, 117.10° E) located in the North China Plain using a high-volume air sampler and pre-combusted quartz filters. Sampling was conducted on day/night or 3 h basis in the period from 29 May to 28 June 2006 during the field burning of wheat straw residue and the post-burning season. The filter samples were analyzed for low-molecular-weight dicarboxylic acids, ketoacids and α-dicarbonyls using capillary gas chromatography (GC) and GC-MS employing water extraction and butyl ester derivatization. Molecular distributions of dicarboxylic acids (C₂-C₁₁, 220–6070 ng m⁻³) were characterized by a predominance of oxalic (C₂) acid (105–3920 ng m⁻³) followed by succinic (C₄) or malonic (C₃) acid. Unsaturated aliphatic diacids, including maleic (M), isomaleic (iM) and fumaric (F) acids, were also detected together with aromatic diacids (phthalic, isophthalic and terephthalic acids). ω-oxocarboxylic acids (C₂-C₉, 24–610 ng m⁻³) were detected as the second most abundant compound class with the predominance of glyoxylic acid (11–360 ng m⁻³), followed by α-ketoacid (pyruvic acid, 3–140 ng m⁻³) and α-dicarbonyls (glyoxal, 1–230 ng m⁻³ and methylglyoxal, 2–120 ng m⁻³). We found that these levels (>6000 ng m⁻³ for diacids) are several times higher than those reported in Chinese megacities at ground levels. The concentrations of diacids increased from late May to early June, showing a maximum on 7 June, and then significantly decreased during the period 8–11 June, when the wind direction shifted from southerly to northerly. Similar temporal trends were found for ketocarboxylic acids and α-dicarbonyls as well as total carbon (TC) and water-soluble organic carbon (WSOC). The temporal variations of water-soluble organics were interpreted by the direct emission from the field burning of agricultural wastes (wheat straw) in the North China Plain and the subsequent photochemical oxidation of volatile and semi-volatile organic precursors emitted from field burning as well as dark ozonolysis of volatile organic compounds and other organics, accretion reactions and oxidation of nonvolatile organics such as unsaturated fatty acids. This study demonstrates that the field burning of agricultural wastes in early summer strongly influenced the air quality of the free troposphere over the North China Plain

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“…Levoglucosan, a saccharide that is used as a tracer for biomass burning (Simoneit et al, 1999), was selected to represent category I. Succinic acid, often identified as one of the most abundant dicarboxylic acids in atmospheric aerosol samples (Rogge et al, 1993;Chebbi and Carlier, 1996;Kerminen et al, 2000;Kawamura et al, 2001a, b;Narukawa et al, 2002, Jung et al, 2010Hegde and Kawamura, 2012), was chosen to represent category II. The humic substances Nordic aquatic fulvic acid reference (NAFA) and Fluka humic acid (HA), obtained from the International Humic Substance Society (IHSS), were chosen as model compounds for category III.…”

mentioning

confidence: 99%

Measuring and modeling the hygroscopic growth of two humic substances in mixed aerosol particles of atmospheric relevance

Zamora

Jacobson

2013

Atmos. Chem. Phys.

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The hygroscopic growth of atmospheric particles affects atmospheric chemistry and Earth's climate. Water-soluble organic carbon (WSOC) constitutes a significant fraction of the dry submicron mass of atmospheric aerosols, thus affecting their water uptake properties. Although the WSOC fraction is comprised of many compounds, a set of model substances can be used to describe its behavior. For this study, mixtures of Nordic aquatic fulvic acid reference (NAFA) and Fluka humic acid (HA), with various combinations of inorganic salts (sodium chloride and ammonium sulfate) and other representative organic compounds (levoglucosan and succinic acid), were studied. We measured the equilibrium water vapor pressure over bulk solutions of these mixtures as a function of temperature and solute concentration. New water activity (a_w) parameterizations and hygroscopic growth curves at 25 °C were calculated from these data for particles of equivalent composition. We examined the effect of temperature on the water activity and found a maximum variation of 9% in the 0–30 °C range, and 2% in the 20–30 °C range. Five two-component mixtures were studied to understand the effect of adding a humic substance (HS), such as NAFA and HA, to an inorganic salt or a saccharide. The deliquescence point at 25 °C for HS-inorganic mixtures did not change significantly from that of the pure inorganic species. However, the hygroscopic growth of HA / inorganic mixtures was lower than that exhibited by the pure salt, in proportion to the added mass of HA. The addition of NAFA to a highly soluble solute (ammonium sulfate, sodium chloride or levoglucosan) in water had the same effect as the addition of HA to the inorganic species for most of the water activity range studied. Yet, the water uptake of these NAFA mixtures transitioned to match the growth of the pure salt or saccharide at high a_w values. The remaining four mixtures were based on chemical composition data for different aerosol types. As expected, the two solutions representing organic aerosols (40% HS/40% succinic acid/20% levoglucosan) showed lower water uptake than the two solutions representing biomass burning aerosols (25% HS/27% succinic acid/18% levoglucosan/30% ammonium sulfate). However, interactions in multicomponent solutions may be responsible for the large variation of the relative water uptake of identical mixtures containing different HSs above a water activity of 0.95. The ZSR (Zdanovskii, Stokes, and Robinson) model was able to predict reasonably well the hygroscopic growth of all the mixtures below a_w = 0.95, but produced large deviations for some multicomponent mixtures at higher values

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Seasonal variations of water-soluble organic carbon, dicarboxylic acids, ketocarboxylic acids, and α-dicarbonyls in Central Himalayan aerosols

Cited by 83 publications

References 90 publications

Molecular composition of dicarboxylic acids, ketocarboxylic acids, α-dicarbonyls and fatty acids in atmospheric aerosols from Tanzania, East Africa during wet and dry seasons

Molecular composition of dicarboxylic acids, ketocarboxylic acids, α-dicarbonyls and fatty acids in atmospheric aerosols from Tanzania, East Africa during wet and dry seasons

High abundances of water-soluble dicarboxylic acids, ketocarboxylic acids and α-dicarbonyls in the mountaintop aerosols over the North China Plain during wheat burning season

Measuring and modeling the hygroscopic growth of two humic substances in mixed aerosol particles of atmospheric relevance

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