Tursić Janja, Grgić Irena, Berner Axel, Skantar Jaroslav, Cuhalev Igor
Laboratory for Analytical Chemistry, National Institute of Chemistry, Slovenia, Hajdrihova 19, SI-1000 Ljubljana, Slovenia.
Environ Sci Technol. 2008 Feb 1;42(3):878-83. doi: 10.1021/es071094g.
A special sampling system for measurements of size-segregated particles directly at the source of emission was designed and constructed. The central part of this system is a low-pressure cascade impactor with 10 collection stages for the size ranges between 15 nm and 16 microm. Its capability and suitability was proven by sampling particles atthe stack (100 degrees C) of a coal-fired power station in Slovenia. These measurements showed very reasonable results in comparison with a commercial cascade impactor for PM10 and PM2.5 and with a plane device for total suspended particulate matter (TSP). The best agreement with the measurements made by a commercial impactor was found for concentrations of TSP above 10 mg m(-3), i.e., the average PM2.5/PM10 ratios obtained by a commercial impactor and by our impactor were 0.78 and 0.80, respectively. Analysis of selected elements in size-segregated emission particles additionally confirmed the suitability of our system. The measurements showed that the mass size distributions were generally bimodal, with the most pronounced mass peak in the 1-2 microm size range. The first results of elemental mass size distributions showed some distinctive differences in comparison to the most common ambient anthropogenic sources (i.e., traffic emissions). For example, trace elements, like Pb, Cd, As, and V, typically related to traffic emissions, are usually more abundant in particles less than 1 microm in size, whereas in our specific case they were found at about 2 microm. Thus, these mass size distributions can be used as a signature of this source. Simultaneous measurements of size-segregated particles at the source and in the surrounding environment can therefore significantly increase the sensitivity of the contribution of a specific source to the actual ambient concentrations.
设计并构建了一种用于直接在排放源处测量粒径分级颗粒的特殊采样系统。该系统的核心部分是一个低压级联冲击器，有10个收集阶段，粒径范围在15纳米至16微米之间。通过在斯洛文尼亚一座燃煤电站的烟囱（100摄氏度）处采样颗粒，证明了其性能和适用性。与用于PM10和PM2.5的商用级联冲击器以及用于总悬浮颗粒物（TSP）的平板装置相比，这些测量结果显示出非常合理的结果。对于TSP浓度高于10毫克/立方米的情况，发现与商用冲击器的测量结果一致性最佳，即商用冲击器和我们的冲击器获得的平均PM2.5/PM10比值分别为0.78和0.80。对粒径分级排放颗粒中选定元素的分析进一步证实了我们系统的适用性。测量结果表明，质量粒径分布通常为双峰，在1 - 2微米粒径范围内质量峰值最为明显。元素质量粒径分布的初步结果显示，与最常见的环境人为源（即交通排放）相比存在一些显著差异。例如，通常与交通排放相关的痕量元素，如铅、镉、砷和钒，通常在粒径小于1微米的颗粒中含量更高，而在我们的特定案例中，它们在约2微米处被发现。因此，这些质量粒径分布可作为该源的特征。因此，同时在源处和周围环境中测量粒径分级颗粒可以显著提高特定源对实际环境浓度贡献的敏感度。
