Abstract We report the determination of ammonia (NH3) diffusive sampling rates for six different designs of commercial diffusive samplers (CEH ALPHA sampler, Gradko diffusion tube, Gradko DIFRAM-400, Passam ammonia sampler, and ICS Maugeri Radiello radial sampler (blue and white turbulence barriers)), together with the validation test results for a pumped sampler (CEH DELTA denuder). The devices were all exposed in the UK's National Physical Laboratory's (NPL) controlled atmosphere test facility (CATFAC). For each of the seven diffusive sampler exposure tests there were traceable concentrations of ammonia (in the range 3–25 μg m−3) generated under well-defined conditions of temperature, relative humidity and wind speed, which are applicable to a variety of ambient monitoring environments. The sampler exposure time at each concentration was 28 days, except for the radial devices, which were exposed for 14 days. The work relied on the dilution of newly developed stable Primary Standard Gas Mixtures (PSMs) prepared by gravimetry in passivated gas cylinders as a method of improving the metrological traceability of ammonia measurements. The exposed diffusive samplers were sent blind to the participants for analysis and the reported NH3 concentrations were then compared against the known reference concentration. From the results for each sampler type a diffusive sampling rate was calculated and compared against the rate used routinely by the participants. Some measurement results were in good agreement with the known traceable reference concentration (particularly for one diffusive sampler design (ALPHA)), while other devices exhibited over-reading and under-reading (each with a clear bias). The new diffusive sampling rates determined in the laboratory study were then applied to measurements in a field comparison campaign, and this was found to deliver an improvement in agreement between the different devices deployed.

中文翻译：

---

使用可追溯的主要标准气体混合物在可控气氛测试设施中验证氨扩散和泵送采样器

摘要 我们报告了六种不同设计的商业扩散采样器（CEH ALPHA 采样器、Gradko 扩散管、Gradko DIFRAM-400、Passam 氨采样器和 ICS Maugeri Radiello 径向采样器（蓝色和白色湍流屏障）），以及泵送采样器（CEH DELTA 剥蚀器）的验证测试结果。这些设备都暴露在英国国家物理实验室 (NPL) 的受控气氛测试设施 (CATFAC) 中。对于七个扩散采样器暴露测试中的每一个，都在明确定义的温度、相对湿度和风速条件下产生了可追踪的氨浓度（范围为 3–25 μg m-3），这些条件适用于各种环境监控环境。每个浓度的采样器暴露时间为 28 天，除了径向装置暴露 14 天。这项工作依赖于在钝化气瓶中通过重量法制备的新开发的稳定初级标准气体混合物 (PSM) 的稀释，作为提高氨测量的计量可追溯性的一种方法。暴露的扩散采样器被盲目发送给参与者进行分析，然后将报告的 NH3 浓度与已知的参考浓度进行比较。根据每种采样器类型的结果，计算了扩散采样率，并将其与参与者常规使用的采样率进行了比较。一些测量结果与已知的可溯源参考浓度非常吻合（特别是对于一种扩散采样器设计 (ALPHA)），而其他设备则表现出过度阅读和阅读不足（每个都有明显的偏差）。然后将实验室研究中确定的新扩散采样率应用于现场比较活动中的测量，发现这可以改善部署的不同设备之间的一致性。