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    Please use this identifier to cite or link to this item: http://ir.cnu.edu.tw/handle/310902800/22240


    標題: Origin of Low-molecular-weight Dicarboxylic Acids and their Concentration and Size Distribution Variation in Suburban Aerosol
    作者: Li-Ying Hsieh
    Chien-Lung Chen
    Meng-Wei Wan
    Cheng-Hsien Tsai
    Ying I. Tsai
    貢獻者: 環境工程與科學系
    醫藥化學系
    關鍵字: Sampling artifacts
    Diurnal variations
    Oxalic acid
    Malonic acid
    Succinic acid
    Tartaric acid
    Inorganic salts
    日期: 2007-09
    上傳時間: 2010-01-15 11:18:09 (UTC+8)
    摘要: PM2.5 aerosol was collected during a PM episode and a non-episodic pollution period between September and November 2004 in suburban southern Taiwan and dicarboxylic acid and inorganic species content and provenance were investigated. Oxalic acid was the dominant dicarboxylic acid species, followed by succinic acid and malonic acid. Tartaric acid concentrations were the lowest. There was 49.3% more dicarboxylic acid in PM episode aerosol than in non-episodic aerosol. However, daily oxalic acid concentration increased 72.7% in PM episode aerosol, while succinic acid fell 20.9% and malonic acid fell 21.6%, indicating higher conversion of these acids into oxalic acid in PM episode aerosol. Dicarboxylic acid concentrations, particularly oxalic acid, peaked at night during the PM episode, due to accumulation of daytime oxalic acid combined with low wind velocity and low mixing layer height at this time. SO42−, NO3− and NH4+ were the dominant ionic species in both PM episode and non-episodic aerosols. NO3− concentration increased 106% during the PM episode, while HNO3, a gaseous precursor of NO3−, fell 57%, indicating a large conversion of HNO3 to aerosol phase NO3− in PM episode aerosol. Backward trajectory data indicate that burning of paddy fields may also contribute to oxalic acid content in PM episode aerosol in the study area, especially during nighttime. Principal component analyses showed that succinic acid, malonic acid and oxalic acid were important factors in both pollution periods and also that there was high correlation between tartaric acid and NOx or HNO2, indicative of vehicle emissions. The mass ratio of oxalic acid to sulfate in this aerosol was as high as 60.3‰, 35.5% higher than in non-episodic aerosol. Principal component analyses showed that photochemical aerosols contributed by succinic acid, malonic acid and oxalic acid were important factors in both periods. There was high correlation between tartaric acid and NOx or HNO2, indicative of vehicle emissions.
    Appears in Collections:[環境工程與科學系(所)] 期刊論文
    [醫藥化學系 ] 期刊論文

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