Role of Methane Sulfonic Acid in Sulfuric Acid-Base Nucleation

JACK JOHNSON, Coty Jen, Carnegie Mellon University

     Abstract Number: 46
     Working Group: Aerosol Chemistry

Abstract
Aerosol nucleation accounts for over half of all seed particles for cloud droplets. In the atmosphere, sulfuric acid (SA) nucleates with ammonia, amines, oxidized organics, and many more compounds to form particles. Studies have shown that methane sulfonic acid (MSA) also contributes to particle formation in the atmosphere. While MSA has been shown to nucleate particles with amines and ammonia, there is still limited knowledge on how MSA and SA nucleate together in the presence of various basic compounds. In this work, we show that SA and MSA react to form particles with ammonia, methylamine, dimethylamine, trimethylamine. Measurements indicate that the formation of the heterodimer of SA and MSA is a significant step in the formation of a particle. These results indicate that to accurately predict particle nucleation rates in the atmosphere, it will be necessary to account of kinetic interactions between SA, MSA, and various amines.