Collaborative Research: Theoretical and Experimental Characterization of the Dynamics of Secondary Organic Aerosol (SOA) Materials

Boston College, Chestnut Hill MA

Investigators

Abstract

This project, funded by the Environmental Chemistry program of the Chemistry Division at the national Science Foundation, investigates the chemical and physical properties of secondary organic aerosol (SOA) particles produced in the atmosphere by reactions of gas-phase organic chemicals (emitted by vegetation, industrial and transportation sources) with ozone and hydroxyl radicals. SOA is a complex mixture of thousands of low-volatility organic species that condense on preexisting atmospheric particles and form a large fraction of atmospheric particulates that impact human health and alter climate and visibility. This collaborative project brings together research groups from Boston College (BC) and Aerodyne Research, Inc. (ARI) with demonstrated expertise in SOA production and measurement of submicron SOA particle properties and a group at the University of California, Berkeley (UCB) with capabilities in modeling the thermodynamic and molecular dynamic properties of liquid, glassy and crystalline organic materials. The project supports a series of laboratory experiments, directed by Professor Paul Davidovits at BC and Dr. Charles Kolb at ARI, that characterize the dynamic properties of mixtures of SOA-like surrogate chemicals as well as laboratory generated SOA particles. The UCB theoretical team, led by Professor David Chandler, is formulating models to reproduce the dynamic properties of SOA measured in thin film deposition and fine particle reactive uptake experiments, with the goal of predicting the impact of relative humidity and temperature on thermodynamic and kinetic properties of SOA/water systems found in the atmosphere. The coupling of fundamental, theoretical, and experimental dynamics of glassy organic material help clarify and codify the roles of SOA in cloud formation, cloud and aerosol radiative properties and cloud precipitation. The project trains students to work in an interdisciplinary team that includes fundamental physical chemists, applied aerosol physicists and atmospheric chemists. The resulting theoretical tools is used by the atmospheric science community to better predict and parameterize SOA particle climate impacts and SOA particle inhalation exposures, with direct societal benefits.