CAREER: Exploring the Physical and Chemical Properties of Light-Absorbing Aerosol: A Single Particle Approach

This CAREER project is focused on the study of the physical and chemical properties of light-absorbing organic aerosol particles in the atmosphere, especially those containing brown carbon (BrC). Fundamental laboratory studies using single particle levitation will be performed to characterize these properties to better understand and predict the role of BrC aerosol in the environment.

This research is expected to lead to an improved description of atmospheric BrC aerosol and their role in clouds, climate, air quality and health.

This effort will characterize the physical state, optical properties, and chemical evolution of model aqueous BrC aerosol to better understand their evolving impacts in the atmosphere. The goals of the proposal are to: (1) Identify the contributions of specific chromophores to the physical state of BrC particles; (2) Characterize the complex refractive index of BrC species in atmospherically relevant proxy particles; and (3) Explore the photochemical aging of BrC particles.

A linear quadrupole electrodynamic balance (LQ-EDB) will be used to levitate micrometer-sized particle samples containing BrC constituents in a controlled environment to mimic atmospheric conditions. New and established tools will be applied to precisely probe the size, refractive index, phase morphology, and composition of suspended samples. The physical state and optical properties of the samples will be measured as a function of relative humidity and their response to photolysis and heterogeneous oxidation will be explored.

A partnership is planned with local resident doctors at Riverside Community Hospital to provide an opportunity to teach the science and health impacts of air quality to populations of students in the local Riverside area.

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.