Ineris, Parc Technologique Alata, Verneuil-en-Halatte, France; Sorbonne Universités, UPMC, PARIS, France.
Ineris, Parc Technologique Alata, Verneuil-en-Halatte, France.
Sci Total Environ. 2021 Feb 25;757:143921. doi: 10.1016/j.scitotenv.2020.143921. Epub 2020 Nov 23.
Twenty-five biogenic and anthropogenic secondary organic aerosol (SOA) markers have been measured over a one-year period in both gaseous and PM phases in the Paris region (France). Seasonal and chemical patterns were similar to those previously observed in Europe, but significantly different from the ones observed in America and Asia due to dissimilarities in source precursor emissions. Nitroaromatic compounds showed higher concentrations in winter due to larger emissions of their precursors originating from biomass combustion used for residential heating purposes. Among the biogenic markers, only isoprene SOA marker concentrations increased in summer while pinene SOA markers did not display any clear seasonal trend. The measured SOA markers, usually considered as semi-volatiles, were mainly associated to the particulate phase, except for the nitrophenols and nitroguaiacols, and their gas/particle partitioning (GPP) showed a low temperature and OM concentrations dependency. An evaluation of their GPP with thermodynamic model predictions suggested that apart from equilibrium partitioning between organic phase and air, the GPP of the markers is affected by processes suppressing volatility from a mixed organic and inorganic phase, such as enhanced dissolution in aerosol aqueous phase and non-equilibrium conditions. SOA marker concentrations were used to apportion secondary organic carbon (SOC) sources applying both, an improved version of the SOA-tracer method and positive matrix factorization (PMF) Total SOC estimations agreed very well between both models, except in summer and during a highly processed Springtime PM pollution event in which systematic underestimation by the SOA tracer method was evidenced. As a first approach, the SOA-tracer method could provide a reliable estimation of the average SOC concentrations, but it is limited due to the lack of markers for aged SOA together with missing SOA/SOC conversion fractions for several sources.
在法国巴黎地区，我们在一年的时间内对气态和 PM 相中的 25 种生物源和人为源二次有机气溶胶 (SOA) 标志物进行了测量。季节性和化学模式与之前在欧洲观察到的模式相似，但与在美洲和亚洲观察到的模式有很大不同，这是由于源前体排放的不同。由于用于住宅供暖的生物质燃烧的前体排放量更大，冬季硝基芳香族化合物的浓度更高。在生物标志物中，只有异戊二烯 SOA 标志物的浓度在夏季增加，而蒎烯 SOA 标志物没有显示出任何明显的季节性趋势。所测量的 SOA 标志物通常被认为是半挥发性物质，主要与颗粒物相有关，除了硝基酚和硝基愈创木酚外，它们的气/粒分配 (GPP) 表现出对温度和有机物质浓度的依赖性。用热力学模型预测它们的 GPP 表明，除了有机相与空气之间的平衡分配外，标志物的 GPP 还受到抑制从混合有机和无机相挥发的过程的影响，例如在气溶胶水相中的增强溶解和非平衡条件。SOA 标志物浓度用于通过 SOA 示踪剂方法的改进版本和正矩阵因子化 (PMF) 分配二次有机碳 (SOC) 源，两种模型的总 SOC 估计值非常吻合，除了在夏季和在一个高度处理的春季 PM 污染事件中，SOA 示踪剂方法的系统低估得到了证明。作为一种初步方法，SOA 示踪剂方法可以提供平均 SOC 浓度的可靠估计，但由于缺乏用于老化 SOA 的标志物以及对几个来源的 SOA/SOC 转化分数的缺失，它受到限制。
