Surface Chemistry of Indoor Air Relevant Organic Compounds on Model Indoor Surfaces: Role of Relative Humidity and Light

In our laboratory, we aim to obtain both quantitative information (rate and extent of reaction) and the detailed molecular processes involved in the chemistry of indoor surfaces using vibrational spectroscopic and quantitative measurements. Various model surfaces are being studied to represent the chemistry on glass surfaces (SiO₂), components of paint and self-cleaning wall surfaces (TiO₂) and component of drywall surface (CaSO₄·2H₂O). The extent to which indoor gases interact with these model indoor surfaces will depend on the chemical composition of the surface and the detailed nature of the heterogenous interactions between gas and surface. The kinetics and extent of adsorption and reaction, as well as surface speciation, depending on surface composition and surface morphology, will be investigated. These surfaces when coated with indoor air relevant organics will change their overall reactivity, the degree to which will depend on the nature of the coating (coverage and thickness). Semi-volatile organics present in the indoor environment from various sources like personal and cleaning products are currently being investigated in our laboratory. Several factors, such as relative humidity and exposure to light, can also play an important role in the surface chemistry of indoor environments. Therefore, the kinetics and extent of adsorption and reaction, e.g. hydrolysis or photochemistry, as well as surface speciation will be explored at different relative humidity and/or in the presence of light. Furthermore, in collaboration with the research groups of Professor Manabu Shiraiwa and Professor Douglas Tobias at UC Irvine, we are integrating the experimental data obtained from our surface chemistry studies with kinetic modeling and atomistic simulations. Through this collaborative effort, we aim to fully understand the molecular level interaction between indoor gases and model surfaces as well as obtain information about the kinetics of different surface processes such as adsorption/desorption.