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首页> 外文会议>Tenth International Conference on Modelling, Monitoring and Management of Air Pollution Jul, 2002 City of Segovia >Chemical analyses and reactions in the characterisation of atmospheric particulates
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Chemical analyses and reactions in the characterisation of atmospheric particulates

机译：表征大气颗粒物的化学分析和反应

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Particulates collected in three New Zealand cities have been characterised using a variety of chemical analyses. Collection was using either a high volume sampler, or a low volume VAPS sampler which provided fine (<2.5 μm) and coarse (2.5 ― 10.0 μm) particulates. Particulate concentrations were measured to indicate overall levels of particulate pollution in the cities. Ion chromatography of the water soluble components was used to determine the sea salt contribution, and the sources of non-sea salt ions associated with the particulates. Elemental analyses (PIXE and ICP-MS) have provided a more detailed source apportionment, with the Auckland brown hazes which appear in calm conditions seen to have a distinct elemental composition. Analysis of the volatile components of particulates has provided insight into the variety of compounds associated with particulates, with specific compounds being useful as indicators of local sources. Particulate PAH concentrations have also been measured and used for source determination. While analysis of chemical composition is useful, it is often assumed that the composition of the particulates does not vary temporally or spatially. However a number processes such as ozone reactions, photochemical reactions, surface deposition, surface evaporation and aging are all now recognised as processes that can operate during the lifetime of a particle and change its characteristics. Consequently in addition to the results of conventional chemical analyses we report on some addition properties of particulates. Laboratory studies in a photochemical cell of the decay of isoprene in the gas phase in the presence of urban particulates have shown that isoprene is lost when the cell is irradiated with simulated sunlight. Also electron paramagnetic resonance measurements have shown that the radical component of particulates can be detected with the signal intensity decreasing with time, suggesting that over a period of hours particles can undergo an aging process with loss of radicals.
机译：使用各种化学分析对在新西兰三个城市收集的颗粒进行了表征。使用高容量采样器或低容量VAPS采样器进行收集，这些采样器提供了细颗粒（<2.5μm）和粗颗粒（2.5〜10.0μm）。对颗粒物浓度进行了测量，以表明城市中颗粒物污染的总体水平。水溶性组分的离子色谱法用于确定海盐的贡献以及与微粒相关的非海盐离子的来源。元素分析（PIXE和ICP-MS）提供了更详细的来源分配，奥克兰褐色雾霾出现在平静的条件下，看起来具有明显的元素组成。对颗粒物挥发性成分的分析提供了对与颗粒物相关的各种化合物的了解，其中特定的化合物可用作指示本地来源的指标。还测量了颗粒状PAH的浓度，并将其用于污染源的确定。尽管化学成分的分析是有用的，但是通常假定颗粒的成分在时间或空间上没有变化。但是，现在已经认识到许多过程，例如臭氧反应，光化学反应，表面沉积，表面蒸发和老化，都是可以在颗粒寿命内运行并改变其特性的过程。因此，除了常规化学分析的结果以外，我们还报告了颗粒的某些附加性质。在光化学电池中，在城市微粒存在下气相中异戊二烯衰减的实验室研究表明，当用模拟阳光照射该电池时，异戊二烯会损失。电子顺磁共振测量还表明，可以检测到颗粒的自由基成分，并且信号强度随时间降低，这表明在数小时的时间内，颗粒可能会经历老化过程而自由基消失。

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