Date of Award

December 2020

Degree Type


Degree Name

Doctor of Philosophy (PhD)




Tara F. Kahan


Atmospheric Chemistry, Indoor Atmospheres, Oxidants, Urban Chemistry, Urban Grime

Subject Categories

Physical Sciences and Mathematics


This work investigates chemistry in two distinct environments in urban atmospheres. The first is the coatings found on urban surfaces often referred to as urban grime. Urban grime may serve as an important medium for photochemical and heterogeneous reactions in cities. This study characterized the composition and physical state of urban grime collected from two American cities. Wavelength-resolved extinction spectra of urban grime samples were also analyzed to improve our understanding of urban grime’s role in photochemistry. The research showed that the grime from the American cities was similar in composition to previous studies conducted in Europe and Canada, but with significant variations in particular ions, such as sulfate in the European samples and chloride in the North American samples. The grime also showed the ability to absorb sunlight which could indicate it may play a role in photochemical reactions. The second focus of this research is quantifying oxidant concentrations in vehicle cabins. Recent research has investigated the oxidative capacity of indoor environments such as homes and commercial buildings, but vehicles are typically overlooked as an indoor environment. However, based on the amount of time people spend in vehicles they are still an important area to study. This research will work to understand how vehicle’s cabin atmosphere compare to both indoor and outdoor environments under several conditions, and thereby understand the kinds of chemical interactions that can be taking place. One of the early findings was that the oxidant levels within the vehicle are more closely aligned with the composition seen in residences compared to commercial buildings or the outdoor environment. Additionally, the level of sunlight that enters the vehicle during the day is significant enough for photochemistry of select oxidants to potentially take place within the cabin.


Open Access