Air pollution poses a growing problem in both developed and developing urban centers. Anthropogenic emissions and their products have strong impacts on human health, leading to an estimated 4 million premature deaths in 2015 alone, predicted to grow to 6.5 million annually by 2040. The Okumura group investigates the chemical kinetics and mechanisms of pollutant-forming oxidation of volatile organic compounds and related atmospheric reactions via spectroscopic, mass spectrometric, and quantum chemical methods.
Anthropogenic emissions impact climate both directly via radiative forcing and indirectly through subsequent oxidation and aerosol-forming aggregation processes. The Okumura group performs laboratory studies in support of remote and direct sensing projects providing spatially and temporally resolved information on sources and sinks of atmospherically relevant species. In addition, we study the formation of secondary organic aerosols, which have complex impacts on climate via scattering, absorption, and modulation of cloud nucleation rates and lifetimes.
Planetary and Astrochemistry
The evolution of the chemical composition of planetary atmospheres is an active area of research. In recent years, the loss mechanism of liquid water from the Martian surface has gained considerable attention, having strong implications in the search for past and present life on Mars. The Okumura group investigates the kinetics of OH and HO2 radicals using spectroscopic techniques, and the roles these reactions might play in Martian water removal. Future interests include study of reactions relevant to other planetary atmospheres.
Kinetic isotope Effect, HOx chemistry of the Martian atmosphere
Developing Laser Techniques
The study of chemical systems of ever-increasing complexity has placed tremendous demands on spectroscopic sensitivity and resolution. In order to study these systems, the Okumura group has been developing and extending techniques in cavity ringdown spectroscopy, photoacoustic spectroscopy, and frequency combs.
Cavity Ringdown Spectroscopy, Photoacoustic Spectroscopy, Frequency Combs