MRI: Acquisition of CI-API-TOFMS (Chemical Ionization Atmospheric Pressure Interface Time-of-Flight Mass Spectrometer) to Measure Condensible Vapors Associated with Fine Particles

大气细颗粒物有机气溶胶是人类呼吸和心血管健康的已知因素，也是气候变化不确定性的来源，尽管有直接和间接的影响。我们还知道，很大一部分(80%-90%)的亚微米(PM1)粒子质量是通过冷凝到达的，而OA在氧化、冷凝、蒸发和进一步的化学转化的动态循环中演化到这种状态。限制我们理解反应路径的一个因素是，许多这些化合物都非常粘性(表面活性)，这给它们的处理和随后的分析带来了挑战。最近开发的仪器，特别是气相化学电离大气压力界面飞行时间-质谱仪(CI-APCI-TOFMS)，提供了在实验室和现场研究中动态分析可缩合有机化合物的前景，在它们达到颗粒大小之前，以及在它们反应和挥发之后。该仪器将主要部署在卡内基梅隆(CMU)空气质量实验室，以支持有机气溶胶研究实验。该实验室是由一组CMU调查人员运营的共享设施，在合作研究和设备共享方面有着悠久的历史。该仪器在设计上也是可现场部署的，从而可以改进对新气溶胶粒子形成的研究。因此，CI-API-TOFMS数据可以为地方、州和国家的监管和政策决策提供信息，最终造福于公众。

Atmospheric fine particle organic aerosol (OA) is a known factor in human respiratory and cardio-vascular health and is also a source of uncertainty in climate change, though direct and indirect effects. It is also known that a very large fraction (80-90%) of the submicron (PM1) particle mass arrives via condensation, and that OA evolves to that state in a dynamic cycle of oxidation, condensation, evaporation, and further chemical transformation. A factor limiting our understanding of the reaction paths is that many of these compounds are extremely sticky (surface active), presenting a challenge to their handling and subsequent analysis. Recently developed instrumentation, specifically gas-phase chemical ionization atmospheric pressure interface time-of flight-mass spectrometry (CI-APCI-TOFMS), offers the promise of dynamically analyzing, both in laboratory and field studies, condensable organic compounds before they either reach particle size, and after they react and volatilize.The instrument will be deployed principally in the Carnegie Mellon (CMU) Air Quality Laboratory to support organic aerosol research experiments. The lab is a shared facility run by a team of CMU investigators with an established history of collaborative research and equipment sharing. The instrument is also field-deployable by design, allowing improved research into new aerosol particle formation. CI-API-TOFMS data may thus inform local, state and national regulatory and policy decisions, ultimately to the public benefit.