A Systematic Comparison between Laboratory Chamber Measurements and Mechanistic Predictions of Complex Oxidation Reactions

JIA JIANG, Lesly Franco Deloya, Erik Helstrom, Havala Pye, Rebecca Schwantes, T. Nash Skipper, Jesse Kroll, Massachusetts Institute of Technology

     Abstract Number: 82
     Working Group: Aerosol Chemistry

Abstract
Recent advancements in laboratory techniques now enable the measurement of multifunctional organic compounds, presenting new opportunities for the development and refinement of atmospheric chemical mechanisms. However, the absence of standardized, systematic approaches limits the application of such datasets for chemical mechanism development. This study aims to bridge this gap by developing a new approach combining laboratory data with an explicit mechanism generator for the comparison against mechanistic predictions. We focus on α-pinene, a major biogenic volatile organic compound known to be an important source of secondary organic aerosol (SOA), and whose oxidation products we have examined in the laboratory under a wide range of chemical conditions. We use these data to evaluate the α-pinene mechanism within the recently-developed Community Regional Atmospheric Chemistry Multiphase Mechanism (CRACMM). Mapping of species measured in the lab to those simulated in the mechanism is done via use of an explicit mechanism generator, the SAPRC Mechanism Generation System (MechGen). This enables the comparison of model outputs with the measured oxidation products in both gas and particle phases. Such comparisons may improve our ability to accurately simulate α-pinene chemistry within models, and more generally provide a new, robust approach for assessment (and ultimately improvement) of atmospheric chemical mechanisms.