The field of atmospheric chemistry encompasses the chemical and physical processes which play key roles in the natural and polluted atmosphere, from urban to remote areas and from the lower to the upper atmosphere. Understanding these processes requires field measurements, the development, testing and application of models, and laboratory studies of kinetics and mechanisms. Research in our laboratory is directed primarily to elucidating the fundamental kinetics, mechanisms and photochemistry of relevant gaseous reactions as well as heterogeneous processes at the surfaces of, and in, particles. We have a number of collaborations with faculty in the Department of Chemistry and Mechanical and Aerospace Engineering, as well as at other institutions, that help to develop an integrated understanding of these systems from the molecular level to ambient air

There are three overall systems of current interest: (1) the reactions of sea salt particles to generate photochemically active halogen gases such as Cl₂, Br₂ and BrCl; (2) reactions of oxides of nitrogen at aqueous interfaces and in thin water films on surfaces to generate HONO and other species such as HNO₃ and N₂O, and (3) reactions of organics in and on particles. Experimental approaches used for elucidating the chemistry of these systems include Knudsen cell studies, long path FTIR, GC and GC-MS, diffuse reflectance infrared Fourier transform spectrometry (DRIFTS) and single reflectance FTIR. Attenuated total reflectance FTIR (ATR-FTIR) is being applied to study the oxidation of organics in real time. In addition, a 560 L aerosol chamber equipped with particle generation and sizing systems, long path FTIR, differential optical absorption spectrometry (DOAS)and atmospheric pressure ionization mass spectrometry (API-MS) is applied to studying the interactions of gases with particles in real time. A second system has been developed in which both gases and the thin aqueous films can both be followed in real time. A new large volume, slow flow aerosol system has recently been constructed, characterized and applied to studies of mechanisms of the formation and growth of new particles from the oxidation of gaseous organic precursors in air

Our research is funded by NSF and DOE. We are part of a collaborative group funded by NSF that is focused on understanding processes at the air-water interface in the atmosphere and their impacts on air quality and global climate change. In this project, experimental, theoretical and airshed kinetics modeling studies are combined to provide a unique approach to understanding processes at the air-water interface and their implications for atmospheric chemistry. This is part of a larger campus-wide group, AirUCI,that integrates research and education in air pollution, energy and air quality, and its impacts on human health.