Development of a Passive Sampler for SOx Monitoring in China

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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.