Abstract View
Examining the Competition Between Oxidation and Deposition in the Fate of Reactive Organic Carbon
GABRIEL ISAACMAN-VANWERTZ, Chenyang Bi, Virginia Tech
Abstract Number: 325
Working Group: Aerosol Chemistry
Abstract
Most of the reactive organic carbon in the atmosphere is emitted in the form of a small number of molecules and compound classes, which undergo photochemical oxidation processes in the atmosphere to form the dynamic and complex mixture of tens of thousands of compounds. To tackle this analytical challenge, a wide range of measurement techniques and modeling frameworks have been developed that classify compounds by their physicochemical properties and/or their molecular formulas. By estimating physicochemical properties of modeled and measured atmospheric oxidation products, we examine the predicted timescales for critical atmospheric transformations, particularly deposition and oxidation. To understand the potential impact of deposition on broader atmospheric chemistry, we place real-world smog chamber data into a framework of competition between loss processes and implement a simple description of deposition into a 0-d box model of photochemical oxidation. We further quantify the extent to which the molecular structure of each compounds impacts the transformations and fates of organic compounds in the atmosphere. A substantial fraction of atmospheric organic compounds is found to have competitive timescales for oxidation and deposition, particularly in the case of semi-volatile oxygenated gases that are likely to form aerosol upon further oxidation. Reactive organic carbon in these transition regimes account for a major fraction of both atmospheric reactivity and potential for secondary aerosol formation, suggesting the need for improved constraints on removal processes to reduce uncertainty in modeled aerosol formation.