H-1 NMR studies of water- and alkaline-soluble organic matter from fine urban atmospheric aerosols


Solution-state H-1 NMR spectroscopy was applied to characterize the structural features of water- and alkaline-soluble organic matter (WSOM and ASOM, respectively) sequentially extracted from fine urban atmospheric aerosols collected over different seasons. The objectives of this study were twofold: (i) to compare the functional characteristics of fine aerosol WSOM and the yet unknown ASOM, and (ii) to assess the sources of WSOM and ASOM at an urban location. The H-1 NMR analysis confirmed that the WSOM and ASOM fractions hold similar 1H functional groups; however, they differ in terms of their relative distribution throughout the seasons. The winter and autumn samples have a less aliphatic and oxidized character and higher contributions from aromatic groups than those of warmer conditions. The urban aerosol WSOM and ASOM fractions do not fit the established H-1 NMR source apportionment fingerprints of marine, secondary, and biomass burning organic aerosols (OAs), exhibiting a smaller relative contribution of carbon-oxygen double bonds, which is indicative of a less oxidized character. These results confirm that the boundaries of the pre-established source categories, especially for secondary and biomass burning OAs, might be different at urban locations, suggesting the need to improve the H-1 NMR source apportionment model for including a new fingerprint for urban OAs. (C) 2015 Elsevier Ltd. All rights reserved.



subject category

Environmental Sciences & Ecology; Meteorology & Atmospheric Sciences


Lopes, SP; Matos, JTV; Silva, AMS; Duarte, AC; Duarte, RMBO

our authors



This work was supported by the Centre for Environmental and Marine Studies (UID/AMB/50017/2013), the Organic Chemistry Research Unit (QOPNA) (UID/QUI/00062/2013), and the Portuguese Science and Technology Foundation (FCT), through the European Social Fund (ESF) and

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