Abstract This work is focused on the relationship between the size distribution of some source tracers of atmospheric particulate matter (PM) and the oxidative potential (OP) of each PM size fraction. Size-segregated PM samples were collected by a multistage impactor (cut-sizes: 0.18, 0.32, 0.56, 1.0, 1.8, 3.2, 5.6, 10 and 18 μm) in two geographical areas of Italy (Rome and Ferrara), characterized by different strength of the main PM sources. The samples were analysed by three different acellular OP methods: dithiothreitol (DTT), dichlorofluorescein diacetate (DCFH) and ascorbate (AA) assay. Elemental (Li, Be, B, Na, Mg, Al, Si, P, K, Ca, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, Ga, As, Se, Rb, Sr, Zr, Nb, Mo, Cd, Sn, Sb, Te, Cs, Ba, La, Ce, W, Tl, Pb, Bi and U) and ionic (Cl−, NO3−, SO42−, Na+, NH4+, K+, Mg2+, Ca2+) composition of the same samples was also determined, in order to trace the contribution of the main PM sources. The size distribution of the OP values was compared to the size distribution of some PM source tracers, with the aim of identifying the PM sources that mostly influence the oxidative properties of atmospheric dust. AA assay resulted to be more sensitive towards coarse particles and OPAA showed a size distribution very similar to that of brake dust tracers. DTT and DCFH assays resulted instead more sensitive towards fine particles. OPDTT and OPDCFH values were comparable at the two sites; sources whose strength was very different in the two monitored areas (secondary contribution and, to a less extent, industrial sources) did not then contribute significantly to the measured OP values. The dimensional behaviour of OPDTT and OPDCFH was consistent with the contribution of biomass burning.

中文翻译：

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意大利城市和工业区大小分离 PM 的氧化潜力

摘要 这项工作的重点是大气颗粒物 (PM) 的一些源示踪剂的尺寸分布与每个 PM 尺寸部分的氧化势 (OP) 之间的关系。通过多级撞击器（切割尺寸：0.18、0.32、0.56、1.0、1.8、3.2、5.6、10 和 18 μm）在意大利的两个地理区域（罗马和费拉拉）收集尺寸分离的 PM 样品，其特征在于不同的PM 主要来源的强度。通过三种不同的脱细胞 OP 方法分析样品：二硫苏糖醇 (DTT)、二氯荧光素二乙酸酯 (DCFH) 和抗坏血酸 (AA) 测定。元素（Li、Be、B、Na、Mg、Al、Si、P、K、Ca、Ti、V、Cr、Mn、Fe、Co、Ni、Cu、Zn、Ga、As、Se、Rb、Sr、 Zr、Nb、Mo、Cd、Sn、Sb、Te、Cs、Ba、La、Ce、W、Tl、Pb、Bi 和 U）和离子（Cl−、NO3−、SO42−、Na+、NH4+、K+、 Mg2+, 还确定了相同样品的 Ca2+) 组成，以追踪主要 PM 来源的贡献。将 OP 值的尺寸分布与一些 PM 源示踪剂的尺寸分布进行比较，目的是确定主要影响大气灰尘氧化特性的 PM 源。AA 分析结果对粗颗粒更敏感，OPAA 显示出与刹车粉尘示踪剂非常相似的尺寸分布。DTT 和 DCFH 检测结果反而对细颗粒更敏感。两个站点的 OPDTT 和 OPDCFH 值相当；在两个监测区域强度差异很大的源（次要贡献，以及在较小程度上，工业源）对测量的 OP 值没有显着贡献。