Development of a Passive Sampler for SOx Monitoring in China

对室外空气环境的可靠认识是分析有害空气污染物风险评价问题的重要参数。在亚洲发展中国家，特别是中国，发现了各种二氧化硫的排放源。尽管这种直接测量是迫切需要的。由于缺乏适当的取样和测量设备，这类测量受到阻碍。为进行空气污染对健康影响的流行病学研究，研制了用于测量个人接触氮氧化物(NO_2和NO)、一氧化碳(CO)和臭氧(O_3)的实用装置，如柳泽滤器徽章。在国际联合研究计划中，我们正在开发一种新的二氧化硫(SO2)被动采样器，该采样器具有组成简单、测量准确的特点，以解决我国大气中SOx污染的各种问题。该方法采用了可以忽略风速影响的分子扩散采样器。过滤浸渍三乙醇胺(TEA)溶液被用作吸收材料。在吸收材料前面使用不锈钢网片，仅测量气体中的SO2。为了准确、快速地分析吸收材料收集的SO3^lt；2-gt；(或SO4^lt；2-gt；)，采用离子色谱(IC法)。然而，该方法受风速的影响较大，会产生测量误差。

Reliable knowledge of outdoor air environment is an important parameter to analyze risk assessment problems on hazardous air pollutants. Various emmision suorces of sulfur oxide (SO_x) are found in Asian developing countries, especially in China. Although this direct measurement is urgently needed. Such measurements have been impeded by the lack of appropriate sampling and measuring devices. Practical devices such as the Yanagisawa filter badge for measuring personal exposure to nitrogen oxide (NO_2 and NO), carbon monoxide (CO) and ozone (O_3) were developed for epidemiological studies of the health effects of air pollution. In the international joint research program, we are now developing a new sulfur dioxide (SO_2) passive sampler with simple composition and precise measurement characteristics to solve various SO_x problems on air pollution in China.We report a high accurate simple method to measure SO_2 concentration. This method is as follows : molecular diffusion sampler that is able to neglect the effect of wind velocity is used. The filter impregnated triethanolamine (TEA) solution is used as a absorbent material. A stainless steel mesh sheet is used in front of a absorbent material to measure gaseous SO_2 only. Ion chromatography (IC method) was used in order to analyze SO_3^<2-> (or SO_4^<2->) collected by absorbent material accurately and rapidly. However, this method was fairly affected by wind velocity to yield a measurement error.