Sampling precautions for the measurement of nitrated polycyclic aromatic hydrocarbons in ambient air
Sampling precautions for the measurement of nitrated polycyclic aromatic hydrocarbons in ambient air
复制标题
环境空气中硝化多环芳烃测定取样注意事项
DOI：
10.1016/j.atmosenv.2007.01.061
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发表时间：
2007
影响因子：
5
通讯作者：
E. Villenave
中科院分区：
文献类型：
--
作者：
A. Albinet;Eva Leoz;H. Budzinski;E. Villenave
由于多环芳烃(PAHs)及其氧化产物，如硝化和氧化的PAHs(NPAHs和opahs)的毒性，其浓度的测定在大气污染控制方面具有重要意义。然后，抽样程序的正常化似乎至关重要。在此背景下，比较了两种不同的采样器(串级冲击器和常规大容量采样器)在不同环境条件下进行的几次现场采样过程中所测得的颗粒物PAH、OPAH和NPAH的浓度。对于冬季和夏季，两种采样系统测定的多环芳烃和多环芳烃浓度被认为是相同的。在夏季，用两种采样设备量化的NPAH浓度相似，而在冬季，传统的大容量采样器将其浓度低估了3-4倍。对于所有17种量化的NPAH，这种低估的比例是相同的。分析误差、采样过程中NPAH的形成以及与采样方法相关的气态氧化剂反应导致的NPAH降解无法解释并行使用的两个采样器之间的差异。一个可能的假设是，冬季对大容量采样器PM10头部的加热会导致采样器内部温度的上升，这可能会加剧NPAHs的化学降解，从而导致对大气中NPAHs浓度的低估。要确认温度对这些化合物的化学降解的重要性，并了解多环芳烃和多环芳烃的不同行为，还需要进行进一步的研究。因此，我们建议使用氧化剂洗涤器，以防止多环芳烃及其衍生物在采样过程中的化学降解。此外，我们建议不要加热采样头，这可能会导致这些降解反应的增加，特别是对NPAHs。
Because of the toxicity of polycyclic aromatic hydrocarbons (PAHs) and of their oxidation products, such as nitrated and oxygenated PAHs (NPAHs and OPAHs), the determination of their concentrations is of great interest in terms of atmospheric pollution control. Then, normalisation of sampling procedures appears essential. In this context, this paper presents a comparison of particulate PAH, OPAH and NPAH concentrations determined with two different samplers (cascade impactor and conventional high volume sampler) installed in parallel during several field sampling campaigns carried out under different environmental conditions. For winter and summer periods, the PAH and OPAH concentrations determined with both sampling systems were considered as equivalent. In the summer period, NPAH concentrations quantified with both sampling devices were similar whereas in the winter period, the conventional high volume sampler underestimated their concentrations by a factor of 3–4. This underestimation was observed in the same proportion for all the 17 quantified NPAHs. Analytical error, NPAH formation during the sampling and NPAH degradation by reaction with gaseous oxidants associated to sampling methodology were unable to explain such differences between both samplers used in parallel. A probable hypothesis is that the heating of the PM10head of the high volume sampler in the winter period generates an increase of the internal sampler temperature that could intensify the chemical degradation of the NPAHs inducing the underestimation of their concentrations in the atmosphere. Further investigations will be necessary to confirm the importance of the temperature on the chemical degradation of these compounds and to understand the different behaviour of PAHs and OPAHs. Consequently, we suggest using oxidant scrubber to prevent chemical degradation of PAHs and derivatives during their sampling. Moreover, we advise against the heating of the sampling head which could induce an increase of these reactions of degradation especially for NPAHs.