CAREER: Aerosol-Water Interactions in the Atmosphere

Bucknell University, Lewisburg PA

Investigators

Abstract

The goal of this project is to study aerosol-water interactions under controlled laboratory conditions and investigate the dependence of water uptake on the physicochemical properties of the aerosol particles. Various aerosol generation and measurement techniques will be used to create realistic aerosols and analyze their interactions with water. These will include imaging of wet and dry nano aerosols with Atomic Force Microscopy (AFM), a cloud condensation nucleus counter (CCNC) for measuring cloud droplet activation, a nano tandem differential mobility analyzer (TDMA) for measuring aerosol population changes after conditioning, an Environmental Scanning Electron Microscope (ESEM) for imaging particle morphology and water interactions of organic particles, SEM for imaging inorganics and for determining residual water presence (via a newly developed technique), and a smog chamber for generating and aging complex aerosols in a controlled environment. Aerosols will be generated with diameters ranging from 3 nm to several microns and widely varying chemical and physical properties, from laboratory organics to ambient biogenic samples. Aerosols will then be analyzed in real time or collected on substrates for later study. The TDMA experiments will permit investigation of aerosol population changes under controlled conditions of temperature, time, and relative humidity. The CCNC experiments involve supersaturation conditions. The ESEM, SEM, and AFM allow imaging of the particles under wet and dry conditions. This combination of instruments and techniques has never before been used in a single, comprehensive study and will allow an improved understanding of aerosol-water interactions and application of the results to the analysis of atmospheric aerosols and to aerosol models. The broader impacts of this proposal include research opportunities for undergraduates at Bucknell University, both within courses and in laboratory research experiences, and a service-learning component for community outreach. Discovery learning laboratories and a new course in particle technology for chemical engineers will also be developed.