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

Carnegie Mellon University, Pittsburgh PA

Investigators

Abstract

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.