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Kimitaka Kawamura - One of the best experts on this subject based on the ideXlab platform.

  • compound specific radiocarbon analysis of low molecular weight Dicarboxylic Acids in ambient aerosols using preparative gas chromatography method development
    Environmental Science and Technology Letters, 2021
    Co-Authors: Zhineng Cheng, Orjan Gustafsson, Kimitaka Kawamura, Biao Jin, Sanyuan Zhu, Tiangang Tang, Bolong Zhang, Gan Zhang
    Abstract:

    Low molecular weight Dicarboxylic Acids constitute a large fraction of atmospheric organic aerosols, which impact atmospheric radiative forcing and hence Earth’s climate. Radiocarbon (14C) is a uni...

  • Dicarboxylic Acids and related compounds in fine particulate matter aerosols in huangshi central china
    Journal of The Air & Waste Management Association, 2019
    Co-Authors: Hongxia Liu, Kimitaka Kawamura, Bhagawati Kunwar, Junji Cao, Jiaquan Zhang, Changlin Zhan, Jingru Zheng, Ruizhen Yao, Ting Liu, Wensheng Xiao
    Abstract:

    PM2.5 (particulate matter with an aerodynamic diameter <2.5 μm) samples were collected in Huangshi, central China, from March 2012 to February 2013 and were analyzed for Dicarboxylic Acids (diAcids...

  • chemical characteristics of Dicarboxylic Acids and related organic compounds in pm2 5 during biomass burning and non biomass burning seasons at a rural site of northeast china
    Environmental Pollution, 2017
    Co-Authors: Fang Cao, Kimitaka Kawamura, Shichun Zhang, Xiaoyan Liu, Chi Yang, Meiyi Fan, Wenqi Zhang, Mengying Bao, Yunhua Chang, Wenhuai Song
    Abstract:

    Fine particulate matter (PM2.5) samples were collected using a high-volume air sampler and pre-combusted quartz filters during May 2013 to January 2014 at a background rural site (47∘35 N, 133∘31 E) in Sanjiang Plain, Northeast China. A homologous series of Dicarboxylic Acids (C2-C11) and related compounds (oxoAcids, α-dicarbonyls and fatty Acids) were analyzed by using a gas chromatography (GC) and GC-MS method employing a dibutyl ester derivatization technique. Intensively open biomass-burning (BB) episodes during the harvest season in fall were characterized by high mass concentrations of PM2.5, Dicarboxylic Acids and levoglucosan. During the BB period, mass concentrations of Dicarboxylic Acids and related compounds were increased by up to >20 times with different factors for different organic compounds (i.e., succinic (C4) acid > oxalic (C2) acid > malonic (C3) acid). High concentrations were also found for their possible precursors such as glyoxylic acid (ωC2), 4-oxobutanoic acid, pyruvic acid, glyoxal, and methylglyoxal as well as fatty Acids. Levoglucosan showed strong correlations with carbonaceous aerosols (OC, EC, WSOC) and Dicarboxylic Acids although such good correlations were not observed during non-biomass-burning seasons. Our results clearly demonstrate biomass burning emissions are very important contributors to Dicarboxylic Acids and related compounds. The selected ratios (e.g., C3/C4, maleic acid/fumaric acid, C2/ωC2, and C2/levoglucosan) were used as tracers for secondary formation of organic aerosols and their aging process. Our results indicate that organic aerosols from biomass burning in this study are fresh without substantial aging or secondary production. The present chemical characteristics of organic compounds in biomass-burning emissions are very important for better understanding the impacts of biomass burning on the atmosphere aerosols.

  • summer and winter variations of Dicarboxylic Acids fatty Acids and benzoic acid in pm 2 5 in pearl delta river region china
    Atmospheric Chemistry and Physics, 2011
    Co-Authors: Shuncheng Lee, Kimitaka Kawamura, Shichun Zou, J J Cao
    Abstract:

    Ground-based PM2.5 samples collected at four different sites in Pearl River Delta region (PRD) during win- ter and summer (from 14 December 2006 to 28 January 2007 in winter and from 4 July to 9 August 2007 in sum- mer) were analyzed for 30 water-soluble organic species, including Dicarboxylic Acids, ketocarboxylic Acids and di- carbonyls, nine fatty Acids, and benzoic acid. Molecu- lar distributions of Dicarboxylic Acids demonstrated that ox- alic acid (C2) was the most abundant species followed by phthalic acid (Ph) in PRD region. The concentrations of total Dicarboxylic Acids ranged from 99 to 1340 ng m 3 , with an average of 438± 267 ng m 3 in PRD. The con- centrations of total ketocarboxylic Acids ranged from 0.6 to 207 ng m 3 (43± 48 ng m 3 on average) while the con- centrations of total -dicarbonyls, including glyoxal and methylglyoxal, ranged from 0.2 to 89 ng m 3 , with an av- erage of 11± 18 ng m 3 in PRD. The total quantified water- soluble compounds (TQWOC) (organic carbon) accounted for 3.4± 2.2% of OC and 14.3± 10.3% of water-soluble OC (WSOC). Hexadecanoic acid (C16:0), octadecanoic acid (C18:0) and oleic acid (C18:1) were the three most abundant fatty Acids in PRD. The distributions of fatty Acids were char- acterized by a strong even carbon number predominance with a maximum (Cmax) at hexadecanoic acid (C16:0). Ratio of C18:1 to C18:0 acts as an indicator for aerosol aging. In PRD, an average of C18:1/C18:0 ratio was 0.53± 0.39, sug- gesting an enhanced photochemical degradation of unsatu- rated fatty acid. Moreover, the concentrations of benzoic acid ranged from 84 to 306 ng m 3 , (165± 48 ng m 3 on av-

  • Dicarboxylic Acids ketocarboxylic Acids α dicarbonyls fatty Acids and benzoic acid in urban aerosols collected during the 2006 campaign of air quality research in beijing carebeijing 2006
    Journal of Geophysical Research, 2010
    Co-Authors: Shuncheng Lee, Kimitaka Kawamura, Yan Cheng, Eri Tachibana, Tong Zhu
    Abstract:

    [1] Ground-based studies of PM2.5 were conducted for determination of 30 water-soluble organic species, including Dicarboxylic Acids, ketocarboxylic Acids and dicarbonyls, nine fatty Acids, and benzoic acid, during the Campaign of Air Quality Research in Beijing 2006 (CAREBeijing-2006; 21 August to 4 September 2006) at urban (Peking University, PKU) and suburban (Yufa) sites of Beijing. Molecular distributions of Dicarboxylic Acids demonstrated that oxalic acid (C2) was the most abundant species, followed by phthalic acid (Ph) and succinic acid (C4) at both sites. The sum of three Dicarboxylic Acids accounted for 71% and 74% of total quantified water-soluble organics (327–1552 and 329–1124 ng m−3) in PKU and Yufa, respectively. Positive correlation was found between total quantified water-soluble species and water-soluble organic compounds (WSOC). On a carbon basis, total quantified Dicarboxylic Acids and ketocarboxylic Acids and dicarbonyls account for up to 14.2% and 30.4% of the WSOC in PKU and Yufa, respectively, suggesting that they are the major WSOC fractions in Beijing. The distributions of fatty Acids are characterized by a strong even carbon number predominance with maximum at hexadecanoic acid (C16:0). The ratio of octadecanoic acid (C18:0) to hexadecanoic acid (C16:0) (0.39–0.85, with an average of 0.36) suggests that in addition to vehicular emissions, an input from cooking emissions is important, as is biogenic emission. Benzoic acid that has been proposed as a primary pollutant from vehicular exhaust and a secondary product from photochemical reactions was found to be abundant: 72.2 ± 58.1 ng m−3 in PKU and 78.0 ± 47.3 ng m−3 in Yufa. According to the 72 hour back trajectory analysis, when the air mass passed over the southern or southeastern part of Beijing (24–25 August and 1–2 September), the highest concentrations of organic compounds were observed. On the contrary, when the clean air masses came straight from the north during 3–4 September, the lowest levels of organic compounds were recorded. This study demonstrates that pollution episodes in Beijing were strongly controlled by wind direction; that is, air quality in Beijing is good when air masses originate from the north and northwest, whereas it deteriorates when the air mass originates from the south and southeast.

Sonia M Kreidenweis - One of the best experts on this subject based on the ideXlab platform.

  • a modeling study of aqueous production of Dicarboxylic Acids 1 chemical pathways and speciated organic mass production
    Journal of Geophysical Research, 2004
    Co-Authors: Barbara Ervens, Graham Feingold, Gregory J Frost, Sonia M Kreidenweis
    Abstract:

    [1] While the formation pathways and thermodynamic properties of inorganic species (e.g., sulphate) in atmospheric aerosols are well understood, many more uncertainties exist about organics. In the present study we present oxidation pathways of organic gas phase species that lead to low volatility organic compounds (C2-C6 Dicarboxylic Acids, pyruvic acid) in both the aqueous and gas phases. This mechanism is implemented in a cloud parcel model initialized with pure (NH4)2SO4 particles in 10 discrete sizes. Under clean continental conditions a few cloud processing cycles produce a total organic mass addition of � 150 ng m � 3 . Individual resuspended aerosol size classes contain significant organic fractions, sometimes higher than 50%. These are likely upper bound estimates of organic mass production. In a polluted, i.e., SO2-rich scenario, about 400 ng m � 3 organic material is produced after about eight cloud cycles. Since the initial conditions in this latter case favor significant production of sulphate, the organic fraction of the aerosol mass after cloud processing represents a much lower percentage of the total aerosol mass. Oxalic, glutaric, adipic, and pyruvic Acids are the main contributors to the organic fraction in both cases. In agreement with observations, the oxalate fraction in processed particles exceeds the fractions of other Dicarboxylic Acids since it represents an end product in the oxidation of several organic gas phase species. The study suggests that cloud processing may act as a significant source of small Dicarboxylic Acids, some fraction of which can be retained in the aerosol phase upon drop evaporation. INDEX TERMS: 0305 Atmospheric Composition and Structure: Aerosols and particles (0345, 4801); 0320 Atmospheric Composition and Structure: Cloud physics and chemistry; 0365 Atmospheric Composition and Structure: Troposphere—composition and chemistry; KEYWORDS: Dicarboxylic Acids, hygroscopicity, organic aerosols

  • a modeling study of aqueous production of Dicarboxylic Acids 1 chemical pathways and speciated organic mass production
    Journal of Geophysical Research, 2004
    Co-Authors: Barbara Ervens, Graham Feingold, Gregory J Frost, Sonia M Kreidenweis
    Abstract:

    [1] While the formation pathways and thermodynamic properties of inorganic species (e.g., sulphate) in atmospheric aerosols are well understood, many more uncertainties exist about organics. In the present study we present oxidation pathways of organic gas phase species that lead to low volatility organic compounds (C2-C6 Dicarboxylic Acids, pyruvic acid) in both the aqueous and gas phases. This mechanism is implemented in a cloud parcel model initialized with pure (NH4)2SO4 particles in 10 discrete sizes. Under clean continental conditions a few cloud processing cycles produce a total organic mass addition of � 150 ng m � 3 . Individual resuspended aerosol size classes contain significant organic fractions, sometimes higher than 50%. These are likely upper bound estimates of organic mass production. In a polluted, i.e., SO2-rich scenario, about 400 ng m � 3 organic material is produced after about eight cloud cycles. Since the initial conditions in this latter case favor significant production of sulphate, the organic fraction of the aerosol mass after cloud processing represents a much lower percentage of the total aerosol mass. Oxalic, glutaric, adipic, and pyruvic Acids are the main contributors to the organic fraction in both cases. In agreement with observations, the oxalate fraction in processed particles exceeds the fractions of other Dicarboxylic Acids since it represents an end product in the oxidation of several organic gas phase species. The study suggests that cloud processing may act as a significant source of small Dicarboxylic Acids, some fraction of which can be retained in the aerosol phase upon drop evaporation. INDEX TERMS: 0305 Atmospheric Composition and Structure: Aerosols and particles (0345, 4801); 0320 Atmospheric Composition and Structure: Cloud physics and chemistry; 0365 Atmospheric Composition and Structure: Troposphere—composition and chemistry; KEYWORDS: Dicarboxylic Acids, hygroscopicity, organic aerosols

  • water uptake of internally mixed particles containing ammonium sulfate and Dicarboxylic Acids
    Atmospheric Environment, 2003
    Co-Authors: A J Prenni, Paul J Demott, Sonia M Kreidenweis
    Abstract:

    Abstract There is increasing evidence that organic compounds comprise a significant fraction of tropospheric particles at all altitudes. The presence of these compounds can affect the particles’ ability to take up water and to form ice in the atmosphere. In this paper we present studies that investigate the hygroscopic behavior of internal mixtures of ammonium sulfate and low molecular weight Dicarboxylic Acids. We find that the ammonium sulfate dominates water uptake behavior for mixtures that contain 100:1 and 10:1 mass ratios of ammonium sulfate:Dicarboxylic acid. However, for 1:1 mixtures, the Dicarboxylic Acids play an important role in determining water uptake characteristics. Observed water contents can be predicted within experimental uncertainties by assuming that each component contributes independently to the total particle water content, in accord with previous measurements for the pure components.

  • the effects of low molecular weight Dicarboxylic Acids on cloud formation
    Journal of Physical Chemistry A, 2001
    Co-Authors: A J Prenni, Paul J Demott, Sonia M Kreidenweis, Eli D Sherman, Lynn M Russell, Yi Ming
    Abstract:

    The ubiquitous presence of organic compounds in tropospheric particles requires that their role in aerosol/cloud interactions be accounted for in climate models. In this paper, we present studies that investigate the hygroscopic behavior of organic compounds and their efficiency as ice nuclei. Specifically, results for soluble and partially soluble Dicarboxylic Acids that have been observed in atmospheric aerosol are discussed. At room temperature, we use a humidified tandem differential mobility analyzer (HTDMA) and a condensation particle counter interfaced with a cloud condensation nuclei counter to characterize the water uptake behavior of these Acids. The HTDMA data agree quite well with modeled hygroscopic behavior. However, we find that some of the compounds retain water to very low humidities, never exhibiting efflorescence. The studies are extended to lower temperatures using a continuous flow ice thermal diffusion chamber to investigate the role of these species in ice nucleation at cirrus condi...

Shuncheng Lee - One of the best experts on this subject based on the ideXlab platform.

  • summer and winter variations of Dicarboxylic Acids fatty Acids and benzoic acid in pm 2 5 in pearl delta river region china
    Atmospheric Chemistry and Physics, 2011
    Co-Authors: Shuncheng Lee, Kimitaka Kawamura, Shichun Zou, J J Cao
    Abstract:

    Ground-based PM2.5 samples collected at four different sites in Pearl River Delta region (PRD) during win- ter and summer (from 14 December 2006 to 28 January 2007 in winter and from 4 July to 9 August 2007 in sum- mer) were analyzed for 30 water-soluble organic species, including Dicarboxylic Acids, ketocarboxylic Acids and di- carbonyls, nine fatty Acids, and benzoic acid. Molecu- lar distributions of Dicarboxylic Acids demonstrated that ox- alic acid (C2) was the most abundant species followed by phthalic acid (Ph) in PRD region. The concentrations of total Dicarboxylic Acids ranged from 99 to 1340 ng m 3 , with an average of 438± 267 ng m 3 in PRD. The con- centrations of total ketocarboxylic Acids ranged from 0.6 to 207 ng m 3 (43± 48 ng m 3 on average) while the con- centrations of total -dicarbonyls, including glyoxal and methylglyoxal, ranged from 0.2 to 89 ng m 3 , with an av- erage of 11± 18 ng m 3 in PRD. The total quantified water- soluble compounds (TQWOC) (organic carbon) accounted for 3.4± 2.2% of OC and 14.3± 10.3% of water-soluble OC (WSOC). Hexadecanoic acid (C16:0), octadecanoic acid (C18:0) and oleic acid (C18:1) were the three most abundant fatty Acids in PRD. The distributions of fatty Acids were char- acterized by a strong even carbon number predominance with a maximum (Cmax) at hexadecanoic acid (C16:0). Ratio of C18:1 to C18:0 acts as an indicator for aerosol aging. In PRD, an average of C18:1/C18:0 ratio was 0.53± 0.39, sug- gesting an enhanced photochemical degradation of unsatu- rated fatty acid. Moreover, the concentrations of benzoic acid ranged from 84 to 306 ng m 3 , (165± 48 ng m 3 on av-

  • Dicarboxylic Acids ketocarboxylic Acids α dicarbonyls fatty Acids and benzoic acid in urban aerosols collected during the 2006 campaign of air quality research in beijing carebeijing 2006
    Journal of Geophysical Research, 2010
    Co-Authors: Shuncheng Lee, Kimitaka Kawamura, Yan Cheng, Eri Tachibana, Tong Zhu
    Abstract:

    [1] Ground-based studies of PM2.5 were conducted for determination of 30 water-soluble organic species, including Dicarboxylic Acids, ketocarboxylic Acids and dicarbonyls, nine fatty Acids, and benzoic acid, during the Campaign of Air Quality Research in Beijing 2006 (CAREBeijing-2006; 21 August to 4 September 2006) at urban (Peking University, PKU) and suburban (Yufa) sites of Beijing. Molecular distributions of Dicarboxylic Acids demonstrated that oxalic acid (C2) was the most abundant species, followed by phthalic acid (Ph) and succinic acid (C4) at both sites. The sum of three Dicarboxylic Acids accounted for 71% and 74% of total quantified water-soluble organics (327–1552 and 329–1124 ng m−3) in PKU and Yufa, respectively. Positive correlation was found between total quantified water-soluble species and water-soluble organic compounds (WSOC). On a carbon basis, total quantified Dicarboxylic Acids and ketocarboxylic Acids and dicarbonyls account for up to 14.2% and 30.4% of the WSOC in PKU and Yufa, respectively, suggesting that they are the major WSOC fractions in Beijing. The distributions of fatty Acids are characterized by a strong even carbon number predominance with maximum at hexadecanoic acid (C16:0). The ratio of octadecanoic acid (C18:0) to hexadecanoic acid (C16:0) (0.39–0.85, with an average of 0.36) suggests that in addition to vehicular emissions, an input from cooking emissions is important, as is biogenic emission. Benzoic acid that has been proposed as a primary pollutant from vehicular exhaust and a secondary product from photochemical reactions was found to be abundant: 72.2 ± 58.1 ng m−3 in PKU and 78.0 ± 47.3 ng m−3 in Yufa. According to the 72 hour back trajectory analysis, when the air mass passed over the southern or southeastern part of Beijing (24–25 August and 1–2 September), the highest concentrations of organic compounds were observed. On the contrary, when the clean air masses came straight from the north during 3–4 September, the lowest levels of organic compounds were recorded. This study demonstrates that pollution episodes in Beijing were strongly controlled by wind direction; that is, air quality in Beijing is good when air masses originate from the north and northwest, whereas it deteriorates when the air mass originates from the south and southeast.

  • Dicarboxylic Acids ketocarboxylic Acids and dicarbonyls in the urban roadside area of hong kong
    Atmospheric Environment, 2006
    Co-Authors: Kimitaka Kawamura, Shuncheng Lee, J J Cao, Tomomi Watanabe, Yan Cheng, Judith C Chow
    Abstract:

    Abstract Homologous Dicarboxylic Acids (C2–C12), ketocarboxylic Acids (ωC2–ωC9, pyruvic acid) and dicarbonyls (glyoxal and methylglyoxal) have been studied in the urban aerosol samples (PM2.5) collected from the Hong Kong roadside atmosphere during winter and summer of 2003 using a capillary GC and GC-MS method. The concentrations of total Dicarboxylic Acids, ketocarboxylic Acids, and α-dicarbonyls were higher in winter than in summer (except for some species like phthalic acid, Ph). Oxalic (C2) acid was found as the most abundant species in summer, followed by Ph. Oxalic (C2) acid was also found as the most abundant species in winter, but followed by malonic (C3) acid. The C2 diacid comprised 28–66% of the total diacid concentrations. The diAcids with higher carbon numbers were less abundant, although C9 diacid was relatively abundant (2%). Glyoxylic acid (ωC2) and methylglyoxal were found as the most abundant ketocarboxylic acid and dicarbonyl in both seasons, respectively. The concentrations of the total diAcids, total ketoAcids and total dicarbonyls ranged from 224 to 1381 ng m−3, 10 to 89 ng m−3 and 5 to 21 ng m−3, respectively. Their relative abundances in PM2.5 mass were 1.18%, 0.06% and 0.02%, respectively. High concentrations of toluene (winter: 33.8 μg m−3; summer: 41.3 μg m−3) and naphthalenes (winter: 1.2 μg m−3; summer: 1.9 μg m−3) observed were one possible source for the abundant phthalic and also methylmaleic Acids detected.

William L. Roberts - One of the best experts on this subject based on the ideXlab platform.

  • analysis of Dicarboxylic Acids by tandem mass spectrometry high throughput quantitative measurement of methylmalonic acid in serum plasma and urine
    Clinical Chemistry, 2001
    Co-Authors: Mark M. Kushnir, Bori Shushan, Francis M. Urry, Gabor Komaromyhiller, William L. Roberts
    Abstract:

    Background: Methylmalonic acid (MMA) is a Dicarboxylic acid whose concentration can be increased in blood and urine in patients with an inborn error of metabolism or vitamin B12 deficiency. We developed a method for the selective analysis of Dicarboxylic Acids that exploits the high specificity of tandem mass spectrometry (MS/MS) and the substantial difference in fragmentation patterns of the isomers methylmalonic (MMA) and succinic acid (SA). Methods: Dicarboxylic Acids were extracted from samples with methyl- tert -butyl ether and derivatized with butanolic HCl to form dibutyl esters. The derivative was injected into the liquid chromatography (LC)-MS/MS system using TurboIonSprayTM (nebulizer-assisted electrospray) ionization and quantified by the multiple reaction monitoring mode of MS/MS. Results: The assay for MMA was linear up to 150 μmol/L. The total imprecision was ≤7.5% at both low and high concentrations. The limits of quantification and detection were 0.1 and 0.05 μmol/L, respectively. The degree of interference from SA could be predicted from the branching ratios of the major product ions. Conclusions: The method is specific for Dicarboxylic Acids. The LC-MS/MS analysis for MMA requires minimal chromatographic separation and takes <60 s per sample. The entire analysis, including sample preparation, for a batch of 100 specimens can be performed in <4 h.

  • Analysis of Dicarboxylic Acids by tandem mass spectrometry. High-throughput quantitative measurement of methylmalonic acid
    2001
    Co-Authors: Mark M. Kushnir, Gabor Komaromy-hiller, Bori Shushan, Francis M. Urry, William L. Roberts
    Abstract:

    boxylic acid whose concentration can be increased in blood and urine in patients with an inborn error of metabolism or vitamin B12 deficiency. We developed a method for the selective analysis of Dicarboxylic Acids that exploits the high specificity of tandem mass spec-trometry (MS/MS) and the substantial difference in fragmentation patterns of the isomers methylmalonic (MMA) and succinic acid (SA). Methods: Dicarboxylic Acids were extracted from sam-ples with methyl-tert-butyl ether and derivatized with butanolic HCl to form dibutyl esters. The derivative was injected into the liquid chromatography (LC)-MS/ MS system using TurboIonSprayTM (nebulizer-assisted electrospray) ionization and quantified by the multiple reaction monitoring mode of MS/MS

Gregory J Frost - One of the best experts on this subject based on the ideXlab platform.

  • a modeling study of aqueous production of Dicarboxylic Acids 1 chemical pathways and speciated organic mass production
    Journal of Geophysical Research, 2004
    Co-Authors: Barbara Ervens, Graham Feingold, Gregory J Frost, Sonia M Kreidenweis
    Abstract:

    [1] While the formation pathways and thermodynamic properties of inorganic species (e.g., sulphate) in atmospheric aerosols are well understood, many more uncertainties exist about organics. In the present study we present oxidation pathways of organic gas phase species that lead to low volatility organic compounds (C2-C6 Dicarboxylic Acids, pyruvic acid) in both the aqueous and gas phases. This mechanism is implemented in a cloud parcel model initialized with pure (NH4)2SO4 particles in 10 discrete sizes. Under clean continental conditions a few cloud processing cycles produce a total organic mass addition of � 150 ng m � 3 . Individual resuspended aerosol size classes contain significant organic fractions, sometimes higher than 50%. These are likely upper bound estimates of organic mass production. In a polluted, i.e., SO2-rich scenario, about 400 ng m � 3 organic material is produced after about eight cloud cycles. Since the initial conditions in this latter case favor significant production of sulphate, the organic fraction of the aerosol mass after cloud processing represents a much lower percentage of the total aerosol mass. Oxalic, glutaric, adipic, and pyruvic Acids are the main contributors to the organic fraction in both cases. In agreement with observations, the oxalate fraction in processed particles exceeds the fractions of other Dicarboxylic Acids since it represents an end product in the oxidation of several organic gas phase species. The study suggests that cloud processing may act as a significant source of small Dicarboxylic Acids, some fraction of which can be retained in the aerosol phase upon drop evaporation. INDEX TERMS: 0305 Atmospheric Composition and Structure: Aerosols and particles (0345, 4801); 0320 Atmospheric Composition and Structure: Cloud physics and chemistry; 0365 Atmospheric Composition and Structure: Troposphere—composition and chemistry; KEYWORDS: Dicarboxylic Acids, hygroscopicity, organic aerosols

  • a modeling study of aqueous production of Dicarboxylic Acids 1 chemical pathways and speciated organic mass production
    Journal of Geophysical Research, 2004
    Co-Authors: Barbara Ervens, Graham Feingold, Gregory J Frost, Sonia M Kreidenweis
    Abstract:

    [1] While the formation pathways and thermodynamic properties of inorganic species (e.g., sulphate) in atmospheric aerosols are well understood, many more uncertainties exist about organics. In the present study we present oxidation pathways of organic gas phase species that lead to low volatility organic compounds (C2-C6 Dicarboxylic Acids, pyruvic acid) in both the aqueous and gas phases. This mechanism is implemented in a cloud parcel model initialized with pure (NH4)2SO4 particles in 10 discrete sizes. Under clean continental conditions a few cloud processing cycles produce a total organic mass addition of � 150 ng m � 3 . Individual resuspended aerosol size classes contain significant organic fractions, sometimes higher than 50%. These are likely upper bound estimates of organic mass production. In a polluted, i.e., SO2-rich scenario, about 400 ng m � 3 organic material is produced after about eight cloud cycles. Since the initial conditions in this latter case favor significant production of sulphate, the organic fraction of the aerosol mass after cloud processing represents a much lower percentage of the total aerosol mass. Oxalic, glutaric, adipic, and pyruvic Acids are the main contributors to the organic fraction in both cases. In agreement with observations, the oxalate fraction in processed particles exceeds the fractions of other Dicarboxylic Acids since it represents an end product in the oxidation of several organic gas phase species. The study suggests that cloud processing may act as a significant source of small Dicarboxylic Acids, some fraction of which can be retained in the aerosol phase upon drop evaporation. INDEX TERMS: 0305 Atmospheric Composition and Structure: Aerosols and particles (0345, 4801); 0320 Atmospheric Composition and Structure: Cloud physics and chemistry; 0365 Atmospheric Composition and Structure: Troposphere—composition and chemistry; KEYWORDS: Dicarboxylic Acids, hygroscopicity, organic aerosols