resumo
The chemical and light-absorption dynamics of organic aerosols (OAs), a master variable in the atmosphere, have yet to be resolved. This study uses a comprehensive multidimensional analysis approach for exploiting simultaneously the compositional changes over a molecular size continuum and associated light-absorption (ultraviolet absorbance and fluorescence) properties of two chemically distinct pools of urban OAs chromophores. Up to 45% of aerosol organic carbon (OC) is soluble in water and consists of a complex mixture of fluorescent and UV-absorbing constituents, with diverse relative abundances, hydrophobic, and molecular weight (Mw) characteristics between warm and cold periods. In contrast, the refractory alkaline-soluble OC pool (up to 18%) is represented along a similar Mw and light-absorption continuum throughout the different seasons. Results suggest that these alkaline-soluble chromophores may actually originate from primary OAs sources in the urban site. This work shows that the comprehensive multidimensional analysis method is a powerful and complementary tool for the characterization of OAs fractions. The great diversity in the chemical composition and optical properties of OAs chromophores, including both water-soluble and alkaline-soluble OC, may be an important contribution to explain the contrasting photo-reactivity and atmospheric behavior of OAs. (C) 2015 Elsevier Ltd. All rights reserved.
palavras-chave
2-DIMENSIONAL LIQUID-CHROMATOGRAPHY; ATMOSPHERIC AEROSOLS; BROWN CARBON; FINE AEROSOL; OPTICAL-PROPERTIES; BLACK CARBON; MATTER; STATE; ABSORPTION; COMPONENTS
categoria
Environmental Sciences & Ecology
autores
Paula, AS; Matos, JTV; Duarte, RMBO; Duarte, AC
nossos autores
Regina Duarte
Bolseiro de pós-DoutoramentoGrupos
agradecimentos
This work was supported by Centre for Environmental and Marine Studies (UID/AMB/50017/2013, University of Aveiro, Portugal) and the Portuguese Science and Technology Foundation (FCT), through the European Social Fund (ESF) and