Ph.D Thesis

Ph.D StudentPetrick Lauren
SubjectInterfacial Oxidation of Squalene and Nicotine in the Indoor
DepartmentDepartment of Civil and Environmental Engineering
Supervisor ASSOCIATE PROF. Yael Dubowski
Full Thesis textFull thesis text - English Version


Indoor chemical reactions play an important role in indoor air quality. It has been observed that heterogeneous chemistry plays a significant part in indoor oxidation reactions. However, large gaps in the current understanding of interfacial indoor chemistry exist. The present research addresses this concern through heterogeneous ozonolysis studies of body chemicals (squalene and bovine serum albumin, BSA) and tobacco smoke (nicotine, second and thirdhand smoke) on model indoor surfaces under environmental conditions similar to those observed indoors (e.g. temperature, air exchange rate (AER), and relative humidity (RH)).

Ozone concentration was found to affect kinetics, where kinetic data from squalene and nicotine reaction could be fitted to a Langmuir-Hinshelwood mechanism. Relative humidity did not affect squalene kinetics but did affect nicotine reaction rate on cellulose. Furthermore, high RH facilitated nicotine desorption from cellulose film, sorption to cotton and nylon, and hindered sorption to polyester and wallboard paper. Temperature affected product distribution and product partitioning between gas and condensed phase. AER affected secondary and tertiary squalene reactions as well as desorption of nicotine. Finally, substrate type affected nicotine sorption, desorption, secondary aerosol formation, and surface kinetics.

Due to high intake fractions and exposure indoors, indoor air quality plays an important role in human health. The information obtained from this research will enhance our understanding of interfacial indoor chemistry and indoor air quality overall.