Probing the Roles of the Surface versus the Bulk in Uptake of Gases Into Atmospherically Relevant Particles

University Of California-Irvine, Irvine CA

Investigators

Abstract

This research project involves an investigation into the role of the atmospheric particle surface versus the particle bulk composition in determining the uptake of organic gases and water into the particle. This information is critical for the development of models to accurately predict the impacts of airborne particles on air quality, visibility and climate. The specific objectives of this research are to: (1) examine the surface and bulk composition of a series of model solid organic particles both before and after heterogeneous oxidation using cutting edge mass spectrometry techniques implemented recently in this laboratory; (2) probe differences in surface vs bulk composition when oxidation of the organic is initiated from the gas phase ("outside in"), or from in-situ photochemistry induced by nitrate or nitrite ion photolysis ("inside out"); and (3) measure uptake of a range of organics as well as water into the above particles, before and after oxidation, in order to establish molecular relationships between gas-particle interactions and surface and bulk composition, and the impacts on particle growth and hygroscopicity. A series of laboratory experiments will be conducted to examine the uptake of a range of organic vapors onto model particles before and after oxidation. The data generated by this effort will provide critical insights to improve predictions of particle impacts on climate, air quality, and human health. This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.