Department of Chemistry & CESAM, University of Aveiro, 3810-193, Aveiro, Portugal.
Department of Chemistry & CESAM, University of Aveiro, 3810-193, Aveiro, Portugal.
Environ Pollut. 2017 Aug;227:513-525. doi: 10.1016/j.envpol.2017.05.011. Epub 2017 May 9.
This study describes and compares the key structural units present in water-soluble organic carbon (WSOC) fraction of atmospheric aerosols collected in different South American (Colombia - Medellín and Bogotá, Peru - Lima, Argentina - Buenos Aires, and Brazil - Rio de Janeiro, São Paulo, and Porto Velho, during moderate (MBB) and intense (IBB) biomass burning) and Western European (Portugal - Aveiro and Lisbon) locations. Proton nuclear magnetic resonance (H NMR) spectroscopy was employed to assess the relative distribution of non-exchangeable proton functional groups in aerosol WSOC of diverse origin, for the first time to the authors' knowledge in South America. The relative contribution of the proton functional groups was in the order H-C > H-C-C= > H-C-O > Ar-H, except in Porto Velho during MBB, Medellín, Bogotá, and Buenos Aires, for which the relative contribution of H-C-O was higher than that of H-C-C=. The H NMR source attribution confirmed differences in aging processes or regional sources between the two geographic regions, allowing the differentiation between urban combustion-related aerosol and biological particles. The aerosol WSOC in Aveiro, Lisbon, and Rio de Janeiro during summer are more oxidized than those from the remaining locations, indicating the predominance of secondary organic aerosols. Fresh emissions, namely of smoke particles, becomes important during winter in Aveiro and São Paulo, and in Porto Velho during IBB. The biosphere is an important source altering the chemical composition of aerosol WSOC in South America locations. The source attribution in Medellín, Bogotá, Buenos Aires, and Lima confirmed the mixed contributions of biological material, secondary formation, as well as urban and biomass burning emissions. Overall, the information and knowledge acquired in this study provide important diagnostic tools for future studies aiming at understanding the water-soluble organic aerosol problem, their sources and impact at a wider geographic scale.
本研究描述并比较了在不同南美的大气气溶胶水溶性有机碳（WSOC）部分中存在的关键结构单元（哥伦比亚-麦德林和波哥大、秘鲁-利马、阿根廷-布宜诺斯艾利斯和巴西-里约热内卢、圣保罗和波多韦柳，在中等（MBB）和强烈（IBB）生物质燃烧期间）和西欧（葡萄牙-阿威罗和里斯本）地点。质子核磁共振（H NMR）光谱首次被用于评估不同来源气溶胶 WSOC 中不可交换质子官能团的相对分布，就作者所知，这在南美的首次应用。质子官能团的相对贡献顺序为 H-C > H-C-C= > H-C-O > Ar-H，但在 MBB 期间的波多韦柳、麦德林、波哥大以及布宜诺斯艾利斯除外，H-C-O 的相对贡献高于 H-C-C=。H NMR 源归属证实了这两个地理区域之间老化过程或区域源的差异，允许区分城市燃烧相关气溶胶和生物颗粒。在夏季，阿威罗、里斯本和里约热内卢的气溶胶 WSOC 比其余地点更具氧化性，表明存在更多的次生有机气溶胶。在阿威罗和圣保罗以及在 IBB 期间的波多韦柳，新鲜排放物，即烟雾颗粒，在冬季变得重要。生物界是一个重要的来源，改变了南美的气溶胶 WSOC 的化学组成。在麦德林、波哥大、布宜诺斯艾利斯和利马的源归属证实了生物物质、二次形成以及城市和生物质燃烧排放的混合贡献。总的来说，本研究获得的信息和知识为未来的研究提供了重要的诊断工具，旨在更广泛的地理范围内了解水溶性有机气溶胶问题、其来源和影响。
