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

大气细颗粒有机气溶胶（OA）是人类呼吸和心血管健康的一个已知因素，也是气候变化的一个不确定性来源，尽管有直接和间接影响。我们还知道，亚微米（PM1）粒子质量的很大一部分（80-90%）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变到这种状态。限制我们对反应路径理解的一个因素是，这些化合物中的许多具有极高的粘性（表面活性），这给它们的处理和后续分析带来了挑战。最近开发的仪器，特别是气相化学电离大气压界面飞行时间质谱（CI-APCI-TOFMS），提供了在实验室和现场研究中动态分析可冷凝有机化合物在达到粒径之前，以及在它们反应和挥发之后的前景。该仪器将主要部署在卡内基梅隆大学（CMU）空气质量实验室，以支持有机气溶胶研究实验。该实验室是一个共享设施，由CMU的一组研究人员运营，他们在合作研究和设备共享方面有着悠久的历史。该仪器也可在现场部署，允许改进对新的气溶胶颗粒形成的研究。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，最终有利于公众利益。

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.