10th International Aerosol Conference
September 2 - September 7, 2018
America's Center Convention Complex
St. Louis, Missouri, USA

Abstract View

Burst of Hydroxyl Radicals in Newly-Formed Cloud Drops

SUZANNE E. PAULSON, Xiaobi Kuang, Jie Rou Chen, David Gonzalez, Peter J. Gallimore, John Scott, UCLA

Abstract Number: 1024
Working Group: Unraveling the Many Facets of Ice Nucleating Particles and Their Interactions with Clouds

Abstract
Photochemical reactions age ambient particles and contribute to cloud processing of inorganic sulfur and organics, changing their chemical composition and enhancing aerosol mass concentrations. We show that during the first few minutes following cloud drop formation, the material in aerosols produces a large burst of hydroxyl radicals, resulting in concentrations in the 0.1 – 5 micromolar OH within the first two minutes. This is more OH than taken up from the gas phase or produced in the next several tens of minutes if the droplets are in bright sunlight. At micromolar concentrations, OH is far above Henry’s law equilibrium. However, even low concentrations of dissolved organics should consume the majority of the OH produced in this initial the burst. Oxidation of organics in cloud drops will be enhanced over that currently in models.