Atmospheric Nucleation Potential of Complex Mixtures

COTY JEN, Jack Johnson, Carnegie Mellon University

     Abstract Number: 21
     Working Group: Aerosol Chemistry

Abstract
Atmospheric aerosol particles can impact Earth's radiation balance and act as the seed for cloud droplet formation. Over half of all the cloud seed particles are formed through nucleation, which is when gas-phase compounds react to form particles. Reactions of sulfuric acid with a wide variety of atmospheric compounds have been previously shown to drive nucleation in the lower troposphere. However, global climate models poorly predict particle nucleation rates since current nucleation models are currently unable to describe particle nucleation rates of complex nucleation reactions. The nucleation potential model (NPM) was recently developed to model sulfuric acid nucleation of complex mixtures of compounds. This work further applies the NPM to show that the model can accurately capture both enhancement and suppression effects of atmospherically relevant compounds such as methanesulfonic acid. NPM is also shown to capture sulfuric acid nucleation rates with a complex mixture of organic and inorganic acids, ambient air, and across a range of atmospherically relevant relative humidities. NPM provides a simple and effective way to estimate how various compounds in a complex mixture enhance sulfuric acid nucleation rates using a condensation particle counter.