AAAR 32nd Annual Conference
September 30 - October 4, 2013
Oregon Convention Center
Portland, Oregon, USA
Abstract View
Aqueous Photooxidation of Fresno, CA and Po Valley, Italy Fogs: Insights into Cloud Processing
JEFFREY R. KIRKLAND, Yong Lim, Stefano Decesari, M. Cristina Facchini, Jeffrey L. Collett, Jr., Barbara Turpin, Rutgers University
Abstract Number: 103 Working Group: Aerosol Chemistry
Abstract This work explores aqueous photooxidation of natural fog water to improve our current understanding of secondary organic aerosol formation through gas followed by aqueous chemistry (aqSOA). Fog waters naturally accumulate an ambient matrix of water-soluble gases formed through photochemical oxidation of anthropogenic and biogenic emissions. We expect that further oxidation of these emissions in the aqueous phase will yield low volatility products that remain in the particle phase after droplet evaporation, thus forming SOA. In this work, we examined changes in the composition of fog water samples after the addition of hydroxyl radicals to improve our understanding of aqSOA formation.
Experiments were conducted with winter fog waters collected in Fresno, California and Po Valley, Italy. Batch aqueous photooxidation reactions were conducted in a 33 mL cuvette chamber with fog samples (organic carbon: 50-350 micro-Molar) and OH radicals. OH radicals were continuously formed in situ through H2O2 photolysis. The concentration dynamics were monitored using ion chromatography (IC), positive and negative mode electrospray-ionization mass spectrometry (ESI-MS), and IC/ESI-MS. Insights will be provided regarding precursors and products identified in these experiments and implications to aqSOA formation in fogs.