Rapid Deposition Prevents the Formation of Late-Generation Products and Aerosols in Real-World Atmospheres

Chenyang Bi, GABRIEL ISAACMAN-VANWERTZ, Virginia Tech

     Abstract Number: 140
     Working Group: Aerosol Chemistry

Abstract
Reactive organic carbon (ROC) species are important fuel for atmospheric chemistry and the formation of secondary organic aerosol. However, deposition can remove these compounds from the atmosphere prior to reaction, with impacts on atmospheric reactivity and aerosol formation downstream. Using a variety of simplified parameterizations based on physicochemical properties of compounds (Henry’s law constant, vapor pressure, and reaction rate constants), we estimate timescales for oxidation and deposition of a wide range of atmospheric compounds and present a framework for predicting and visualizing the fate of a molecule. While some compounds have relatively determined fates, a substantial portion of compounds have competitive fates between oxidation and deposition. We implement deposition into chemically explicit and volatility binned 0-dimensional box models, and find that deposition significantly suppresses the reactivity and aerosol formation of the atmosphere by removing early-generation products. Furthermore, deposition prevents the formation of large fractions (up to 90%) of downstream, late-generation compounds. The results of this study imply that formation of aerosol from multi-generational oxidation may be less important in ambient atmosphere than often considered, and that efforts to correct for deposition to walls in chamber experiments may be substantially overestimating aerosol formation.