含碳气溶胶采样偏差评估研究

Up to now, air pollutent PM2.5 has caused wide concern. As the main part of atmospheric particles,especially fine particles（PM2.5）, carbonaceous aerosol has been the hot piont of PM research field. The proper sampling approch of carbonceous aerosol is the basic step for research work and it is the crucial point for post-sampling chemical analysis,data process and result evaluation. Fiter-based aerosol sampling is still very common for an extended period of time.The quartz filter has a large surface area upon which adsorption of gaseous organics could occur, causing the positive artifact. On the other hand, volatilization of the collected particulate organic carbon would induce the negative artifact. How to minnimze or eliminate the artifacts during sampling process was essential proper sampling approches.In this study, a series field experiments would be performed in order to quantify the sampling artifacts with medium-volume samplers, further more, the rule of artifacts change with temperature and sampling flow rate would be investagated.

当前PM2.5污染引起人们的广泛关注，含碳气溶胶是环境空气颗粒物尤其是细颗粒物（PM2.5）的重要组成部分,已经成为颗粒物研究领域的热点。含碳气溶胶样品的正确采集对于样品后续的测试、数据分析以至结果评估都至关重要,是研究过程的基础环节。滤膜采样作为颗粒物研究中的主要方法，在采样过程中滤膜对有机气体的吸附以及含碳颗粒物中所含的挥发、半挥发性有机物质的挥发将会带来采样偏差。如何处理半挥发性有机物的吸附与挥发给采样过程带来的偏差是含碳颗粒采样技术的难点与关键。本研究主要针对该问题，设计系列现场试验开展研究，以期定量推估使用中流量采样系统采集细颗粒物时采样偏差的大小，并进而探寻采样偏差随采样温度以及采样流量变化的规律。

含碳颗粒物是大气气溶胶的重要组成部分,含碳颗粒物样品的正确采集对于后续样品测试、数据分析、结果评估至关重要,是研究过程的基础环节。如何处理半挥发性有机物的吸附与挥发给采样过程带来的偏差是含碳颗粒采样技术的难点与关键。本研究主要针对该问题，建立了评估含碳颗粒物采样偏差的系统性研究方法，试制了适合国内采样器使用的溶蚀器，采用石英滤膜-石英滤膜串联的QBQ方法、Teflon滤膜-石英滤膜串联的QBT方法，以及溶蚀器与QBQ、QBT相连的方法，对含碳颗粒物采样的正偏差和负偏差进行评估。并从采样流速、环境温度、采样高度和粒径等不同方面分析了影响含碳颗粒物采样偏差的影响因素。