Abstract View
Oxidized Amines Enhance Particle Formation More Than Amines
NANNA MYLLYS, Tuomo Ponkkonen, Sabrina Chee, James Smith, University of California, Irvine
Abstract Number: 505
Working Group: Aerosol Chemistry
Abstract
Sulfuric acid plays a key role in atmospheric aerosol particle formation. Bases such as amines are known to stabilize sulfuric acid to form particles through salt formation. However, the role of oxidized amines in particle formation and growth is unknown. Trimethylamine oxide (TMAO), an oxidization product of trimethylamine, is studied here. As a weak base in the aqueous phase and a strong base in the gas phase, TMAO offers an interesting perspective for an argument “base strength is a key factor in particle formation.” Another intriguing property of TMAO is related to its molecular structure: while steric hinderance of three methyl groups limits the hydrogen bonding sites to one, the zwitterionic bond causes a high dipole moment which enables the formation of stabilizing ion-dipole interactions. It seems clear that more than one base property is related to its capability to enhance aerosol particle formation. Molecular-level cluster formation mechanisms are resolved, and theoretical results on particle formation are confirmed with laboratory measurements. The enhancing effect of TMAO is compared to the other atmospheric bases and the factors, which make oxidized amines stronger stabilizer in clustering than amines, are discussed.