CAREER: Impacts of the Chemical and Physical Properties of Surfactants on the Hygroscopic Growth of Atmospheric Aerosol Particles

This CAREER project focuses on the study of surfactant compounds in atmospheric aerosol and their effects on particle hygroscopic growth. Field collections and laboratory experiments using high resolution chemical and physical analyses will be used to assess the influence of surfactant molecular composition and associated properties on the hygroscopic growth of atmospheric particles. Hygroscopic growth can alter particle size and composition, both of which are important determinants in the influence of aerosol particles on visibility and human health. The effect of surfactants on particle hygroscopic growth is expected to be nonlinear and dependent on the surfactant molecular composition, structure, and critical micelle concentration. The experimental plan will address the following questions: (1) What are the compositions, structures, and interfacial properties of surfactants in atmospheric aerosol particles? How do these surfactant characteristics vary as a function of particle size and air mass source region (e.g., natural, anthropogenic, marine, aged influences)? (2) What effects do surfactant structure, composition, and interfacial properties have on the hygroscopic growth of submicron and supermicron aerosol particles? Chemical and physical measurements of aerosol particles collected as part of two field campaigns at the Skidaway Institute of Oceanography, on the coast of Georgia, will be made during two seasons to capture seasonal variability. Laboratory experiments will also be conducted to measure the hygroscopic growth of model laboratory-generated aerosol particles to determine the influence of the surfactant fraction directly. Multivariate statistics will be used to determine the surfactant properties in different particle types. The education and outreach plan includes working with high school students to collect local air quality measurements, developing a new laboratory course to explore the principles of analytical chemistry through measurements of aerosol chemistry, and conducting a first-year research seminar course and a summer research experience for undergraduate students. 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.