Physicochemical characterisation of combustion particles from vehicle exhaust and residential wood smoke
Physicochemical characterisation of combustion particles from vehicle exhaust and residential wood smoke
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DOI：
10.1186/1743-8977-3-1
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发表时间：
2006-01-01
影响因子：
10
通讯作者：
Namork, Ellen
中科院分区：
文献类型：
--
作者：
Kocbach, Anette;Li, Yanjun;Namork, Ellen
背景：暴露在环境颗粒物中与许多不利的健康影响有关。颗粒的大小、比表面积和化学等特性似乎都会影响颗粒的负面效应。本研究对目前生物实验中使用的汽车尾气和木材烟雾的燃烧颗粒物进行了微观结构和化学分析。方法：在公路隧道中收集两个季节的汽车尾气颗粒物，分别使用和不使用立柱轮胎，而从炉子中收集单级燃烧的木材烟雾。此外，还对参考柴油样品(SRM 2975)进行了分析。用透射电子显微镜技术(TEM/HRTEM、EELS和SAED)对样品进行了表征。用热光透射法测定了样品中元素碳和有机碳的含量，用气相色谱-质谱法测定了所选多环芳烃的含量。结果：透射电子显微镜检测到的唯一燃烧颗粒物是由数万至数千个球形初级颗粒组成的碳聚集体。隧道样本中还含有来自道路磨损的矿物颗粒。汽车尾气中原始碳颗粒的几何直径(24+/-6 nm)明显小于木材烟雾中的几何直径(31+/-7 nm)。此外，HRTEM显示，两种来源的初级颗粒物都表现出涡流层状微结构，由同心碳层围绕着汽车尾气中的几个原子核或木材烟雾中的单个原子核组成。然而，用SAED和EELS检测到两种来源的初级颗粒的石墨化特征没有差异。与汽车尾气相比，木烟燃烧颗粒物的总多环芳烃含量较高，但有机碳与总碳的比例没有来源差异。结论：汽车尾气和居民木烟燃烧颗粒物的初级颗粒直径、微观结构和多环芳烃含量不同。此外，所分析的样品似乎适合于评估颗粒的物理化学特性对生物反应的影响。
Background: Exposure to ambient particulate matter has been associated with a number of adverse health effects. Particle characteristics such as size, surface area and chemistry seem to influence the negative effects of particles. In this study, combustion particles from vehicle exhaust and wood smoke, currently used in biological experiments, were analysed with respect to microstructure and chemistry.Methods: Vehicle exhaust particles were collected in a road tunnel during two seasons, with and without use of studded tires, whereas wood smoke was collected from a stove with single-stage combustion. Additionally, a reference diesel sample (SRM 2975) was analysed. The samples were characterised using transmission electron microscopy techniques (TEM/HRTEM, EELS and SAED). Furthermore, the elemental and organic carbon fractions were quantified using thermal optical transmission analysis and the content of selected PAHs was determined by gas chromatography-mass spectrometry.Results: Carbon aggregates, consisting of tens to thousands of spherical primary particles, were the only combustion particles identified in all samples using TEM. The tunnel samples also contained mineral particles originating from road abrasion. The geometric diameters of primary carbon particles from vehicle exhaust were found to be significantly smaller (24 +/- 6 nm) than for wood smoke (31 +/- 7 nm). Furthermore, HRTEM showed that primary particles from both sources exhibited a turbostratic microstructure, consisting of concentric carbon layers surrounding several nuclei in vehicle exhaust or a single nucleus in wood smoke. However, no differences were detected in the graphitic character of primary particles from the two sources using SAED and EELS. The total PAH content was higher for combustion particles from wood smoke as compared to vehicle exhaust, whereas no source difference was found for the ratio of organic to total carbon.Conclusion: Combustion particles from vehicle exhaust and residential wood smoke differ in primary particle diameter, microstructure, and PAH content. Furthermore, the analysed samples seem suitable for assessing the influence of physicochemical characteristics of particles on biological responses.