New Particle Formation from Methanesulfonic Acid, Ammonia and Amines: Developing a Mechanistic Basis for Global Models
Authors
Barbara J Finlayson-Pitts — University of California
Haihan Chen — University of California Irvine
Matthew L Dawson — University of California, Irvine
Kristine Arquero — University of California Irvine
Michael Ezell — University of California
Veronique Michele Lucie Perraud — University of California
Mychel E. Varner — University of California, Irvine
R. B. Gerber — University of California, Irvine
Andrew Scott Martinez — University of California, Irvine
Donald Dabdub — University of California
Category
New Particle Formation
Description
In a number of locations, methanesulfonic acid (MSA) formed from the oxidation of organosulfur precursors has been measured in the gas phase at concentrations ~ 10-100% of that of co-existing sulfuric acid. Recent studies in this laboratory established that in contrast to earlier predictions, MSA does lead to new particle formation in air in the presence of ammonia and amines, and that water plays a central role. The results of experimental studies in which the structures and concentrations of amines, as well as relative humidity, were varied will be presented as the basis of a new mechanistic understanding of these reactions. The reaction scheme is supported by computational studies of important clusters and intermediates. This new chemistry is being incorporated into an airshed model whose predictions for amines are tested using a new technique developed to measure amines in air at the tens of ppt level. This combination of theory, computation, field measurements and regional modeling provides an integrated approach to providing an accurate representation of new particle formation from these processes that can ultimately be incorporated into global models.Lead PI
Barbara J Finlayson-Pitts — University of California