Development of a Passive Sampling/Monitoring Device Suitable for Acid Gas in Atmospheric Environment in China and Its Field Evaluation

A new type of passive samplerwhich can ily determine sulfur dioxide (SO - D22 - D2) and nitrogen dioxide （NO - D22 - D2）simultaneously air,has developed. The passive sampling method for analysis of SO - 22 - 2 has more difficult thanNO D22 D2 chiefly because of following two problems. The first one is that SO D22 D2 has highabsorptivity . therefore,这是much absorbed in the materials used as the absorption and diffusion filter in sampler，and the second one is the sulfate ion, to which absorbed SO D22 D2 is oxidized，通常在过滤器中使用的样本部分。Thus，blank concentration of sulfur ion is sampler is higher. As a result of exposure experiments using awind tunnel to evaluate the materials used as absorption and diffusion filter，passive sampler which polyethelene membrane is used as an absorption layer，polyethylene and polypropylene as the first and second diffusion layer was found to have themost suitable sampler for analyzing SO - D22 - D2 and NO - D22 - D2. The precision and detection limit这个方法被发现是一个satisfactory.在这个研究之前应用的方法to the evaluation of air quality at the five major cities in China since September 1997. the passivesamplers are easily influence by wind. However新开发samplers are found to have minimum influence by sampling conditions such aswind， humidity和temperature.所以这个方法是应用于投资在six cities，Beijing, Lonzhou, Wuhan, Dalian，Shenyang which are high in China. The concentrations of SO SO D22 - D2 and NO D22 - D2 are two daysaverages.这些obtained data has good agreement with the annual average concentration. the weeklychange of SO D22 - D2 and NO D22 - D2 concentration (7 days average) in Beijing. Since temperaturedropped,D22 - D2 and NO D22 - D2 concentrations tend to increase. One of the causes of it is the increaseof using coal for heating。

A new type of passive sampler, which can easily determine sulfur dioxide (SOィイD22ィエD2) and nitrogen dioxide (NOィイD22ィエD2) simultaneously air, has developed. The passive sampling method for analysis of SOィイD22ィエD2 has more difficult than NOィイD22ィエD2 chiefly because of following two problems. The first one is that SOィイD22ィエD2 has high absorptivity. Therefore, it is much absorbed in the materials used as the absorption and diffusion filter in sampler, and the second one is that the sulfate ion, to which absorbed SOィイD22ィエD2 is oxidized, is usually contained in filter used as sampler parts. Thus, blank concentration of sulfur ion is sampler is higher. As a result of exposure experiments using a wind tunnel to evaluate the materials used as absorption and diffusion filter, the passive sampler which polyethelene membrane is used as an absorption layer, and polyethylene and polypropylene as the first and second diffusion layer was found to have the most suitable sampler for analyzing SOィイD22ィエD2 and NOィイD22ィエD2. The precision and detection limit of this method was found to be satisfactory. The method established in this study has been applied to the evaluation of air quality at the five major cities in China since September 1997.The passive samplers are easily influence by wind. However, the newly developed samplers are found to have minimum influence by sampling conditions such as wind, humidity and temperature. So this method is applied to investigate the air in six cities, Beijing, Lonzhou, Wuhan, Dalian, Shenyang which are high in China. The concentrations of SOィイD22ィエD2 and NOィイD22ィエD2 are two days averages. These obtained data has good agreement with the annual average concentration. The weekly change of SOィイD22ィエD2 and NOィイD22ィエD2 concentration (7 days average) in Beijing. Since temperature dropped, SOィイD22ィエD2 and NOィイD22ィエD2 concentrations tend to increase. One of the causes of it is the increase of using coal for heating.