What's in the air? The prevalence and health effects of particulate reactive oxygen species.
The objective of my dissertation research is to understand the fundamental health effects of reactive oxygen species (ROS) and the principle parameters that influence the indoor and outdoor concentrations of ROS. ROS are an important class of secondary air pollutants generated from photochemical reactions in outdoor air and ozone-initiated reactions in indoor air. While ROS are produced naturally in the body to defend against foreign organisms, exposure to excessive levels of ROS can induce cell injury and has been implicated in many pulmonary diseases. In this research, the concentration of ROS on respirable particles was assessed in residential, institutional and retail buildings. The data indicates that the concentration of ROS inside buildings can be higher than the outdoor ROS concentration, and on average it is 1.8 times higher. High indoor ROS concentrations can have important implications on our health, given the large proportion of time we spend indoors. Furthermore, an in vitro exposure model was used to assess the inflammatory response of human lung cells to products from ozone-initiated reactions. It was found that lung cells produce higher levels of inflammatory proteins upon exposure to a mixture of d-limonene and ozone (used as a model system to generate oxygenated organic species). Overall, this research highlights the prevalence of products from ozone-initiated reactions in the environments in which we spend most of our time and the importance of reducing our exposure to these pollutants.