MRI: Development of a A Wide-Range Impactor Particle Sampler (WRIPS) for Near-Real Time Analysis of Atmospheric Particulate Matter

空气中的颗粒物（PM）会对健康造成不良影响，在气候变化中起着重要作用，影响雾霾的形成，并降低能见度。此外，与PM相关的污染物沉积是许多生态系统的重要输入。由于这些原因，迫切需要能够在足够短的时间尺度上测量PM和PM相关污染物的技术，以便可以表征这些颗粒的来源并开发其化学和命运的机制模型。由于这些特性取决于颗粒大小，新技术还应该能够在表征PM之前按尺寸分离PM。这些仪器的另一个要求是，它们在收集之前从气流中分离颗粒，以避免采样伪像。一种仪器，满足这种具有挑战性的组合需求，几乎实时测量尺寸分离的PM，没有采样工件，将是本研究的核心成果。这种独特的仪器可用于测量任何与PM相关的化合物，这些化合物可以在850℃的温度下转化为气相（例如汞，有机碳和元素碳，农药和许多其他有机化合物），然后用实时检测器进行检测（例如汞的冷蒸汽原子荧光，或农药的质量分光光度计）。该仪器将被设计成可以使用不同的载气来适应这些不同的分析技术。作为该项目的一部分，我们还将开发创新技术来评估气溶胶风洞中的颗粒采样器。这些技术将变得越来越重要，因为新的粒子采样器被开发出来，以响应PM日益增长的兴趣。拟议的开发项目将与NSF MRI计划相关，通过解决当前原位，大小分类气溶胶测量能力的局限性，并允许开发最先进的实时颗粒表征仪器。

0521137HolsenAirborne particulate matter (PM) can cause adverse health effects, plays a significant role in climate change, impacts smog formation, and decreases visibility. In addition, deposition ofpollutants associated with PM is a significant input to many ecosystems. For these reasons there is an urgent need for techniques that can measure PM and PM-associated pollutants at short enough time scales that sources of these particles can be characterized and mechanistic models of their chemistry and fate developed. Since these properties are dependent on particle size, the new technique should also be able to separate the PM by size before they are characterized. An additional requirement of these instruments is that they separate particles from the gas stream before collection to avoid sampling artifacts.An instrument that meets this challenging combination of requirements for near real-time measurement of size-segregated PM without sampling artifacts will be a central outcome of this research. This unique instrument could be used to measure any compound associated with PM that can be converted to the gas phase at temperatures 850C (for example Hg, organic and elemental carbon, pesticides and numerous other organic compounds) and then detected with a real-time detector (for example cold vapor atomic fluorescence for Hg, or a mass spectrophotometer for pesticides). The instrument will be designed so that different carrier gases can be used to accommodate these different analytical techniques. As a part of this project, we will also develop innovative techniques to evaluate particle samplers in an aerosol wind tunnel.These techniques will become increasingly important as new particle samplers are developed in response to the growing interest in PM. The proposed development project will be of relevance to the NSF MRI Program by addressing the limitations in current in-situ, size-classified aerosol measurement capabilities and allowing for the development of state-of-the-art instrument for real-time particle characterization.