title: Chemical Structural Characteristics of HULIS and Other Fractionated Organic Matter in Urban Aerosols: Results from Mass Spectral and FT-IR Analysis.
abstract: The chemical characteristics of complex organic matter in atmospheric aerosols remain poorly understood. Water-insoluble organic matter (WISOM) and water-soluble organic matter (WSOM) in the total suspended particulates collected in the city of Nagoya in summer/early autumn and winter were extracted using multiple solvents. Two fractions of humic-like substances, showing neutral and acidic behavior (HULIS-n and HULIS-a, respectively), and the remaining highly polar part (HP-WSOM) were fractionated from WSOM using solid phase extraction. The chemical structural characteristics and concentrations of the organic matter were investigated using mass spectrometry and Fourier transform infrared (FT-IR) spectroscopy. WISOM and HULIS-n had low O/C ratios (0.1 and 0.4, respectively) and accounted for a large fraction of the organics in aerosols (70%). HULIS-a and HP-WSOM had higher O/C ratios (0.7 and 1.0, respectively), and their concentrations in summer and early autumn were on average ∼2 times higher than those in winter. The mass spectrum and FT-IR analyses suggest the following: (1) WISOM were high-molecular-weight aliphatics (primarily C27-C32) with small proportions of -CH3, -OH, and C═O groups; (2) HULIS-n was abundant in aliphatic structures and hydroxyl groups (primarily C9-C18) and by branched structures; (3) HULIS-a and HP-WSOM contained relatively large amounts of low-molecular-weight carboxylic acids and alcohols (primarily C4-C10); and (4) WISOM and HULIS-n were relatively abundant in amines and organic nitrates.
authors.affiliation: Graduate School of Environmental Studies, Nagoya University , Nagoya, Japan.
authors.forename: Qingcai
authors.initials: Q
authors.lastname: Chen
authors.affiliation: Graduate School of Environmental Studies, Nagoya University , Nagoya, Japan.|Nagoya City Institute for Environmental Sciences, Nagoya, Japan.
authors.forename: Fumikazu
authors.initials: F
authors.lastname: Ikemori
authors.affiliation: Fukuoka City HAKATA Health & Welfare Center, Fukuoka, Japan.
authors.forename: Hayato
authors.initials: H
authors.lastname: Higo
authors.affiliation: Osaka City Institute of Public Health and Environmental Sciences, Osaka, Japan.
authors.forename: Daichi
authors.initials: D
authors.lastname: Asakawa
authors.affiliation: Graduate School of Environmental Studies, Nagoya University , Nagoya, Japan.
authors.forename: Michihiro
authors.initials: M
authors.lastname: Mochida
mesh_terms: D000336:Aerosols / Q000032:analysis* / Q000737:chemistry*; D000397:Air Pollution / Q000032:analysis*; D002947:Cities; D004784:Environmental Monitoring / Q000379:methods; D006812:Humic Substances; D007564:Japan; D013058:Mass Spectrometry / Q000379:methods; D009930:Organic Chemicals / Q000032:analysis; D052638:Particulate Matter / Q000032:analysis*; D012621:Seasons; D052616:Solid Phase Extraction; D012995:Solubility; D017550:Spectroscopy, Fourier Transform Infrared; D014867:Water / Q000737:chemistry
chemical_list: D000336:Aerosols; D006812:Humic Substances; D009930:Organic Chemicals; D052638:Particulate Matter; D014867:Water