CAREER:A Comprehensive Assessment of the Reactive Oxygen Species Activity of Ambient Fine Particulate Matter and its association with the Chemical Composition

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Air pollution particles are complex mixtures of organic and inorganic components. Due to their small size, particles smaller than 2.5 microns (called PM2.5) can be inhaled deep into human lungs. Once there, PM2.5 can cause damage to lung tissues by generating oxidants. PM2.5 levels are measured by mass abundance, but this metric does not predict health risk because different particles create different amounts of oxidants. The goal of this research is to develop an automated instrument to measure the capability of PM2.5 to generate oxidants. Particle constituents that generate oxidants will be quantified using novel chemical characterization and modeling. Successful development of this technology will transform our ability to rapidly measure health risk. Interactive summer camps involving high school students and teachers will be organized and an online module to assess PM2.5 exposure risk will be developed. Societal benefits will result from increasing scientific literacy and broadening participation of youth from diverse backgrounds in environmental engineering and public health.Ambient PM2.5 is the fifth largest risk factor contributing to global burden of disease. Despite the confirmed association of PM2.5 mass concentrations with various human diseases, there is a significant gap in our knowledge of how they PM2.5 causes adverse health effects. The capability to generate reactive oxygen species (ROS) is an important property of PM2.5 that may be the missing link between these associations. There are two major challenges in the widespread adoption of ROS as a measure of risk. First, ROS measurement is laborious and time-consuming in comparison to easily measured bulk PM2.5 mass. Second, we lack a mechanistic understanding of how particulate chemical components catalyze ROS generation. This project will develop an automated instrument for measuring all biologically plausible modes of ROS activity of ambient PM2.5. The instrument will be used to analyze the ROS activity of ambient PM2.5 samples collected from six sites in the Midwest US. The extensive dataset of ambient PM2.5 ROS activity will be integrated with a detailed chemical characterization scheme to identify the chemical components associated with different modes of ROS generation. The contribution of each component to total ROS activity will be quantified by applying regression-based modeling techniques. Successful development of a rapid and accurate identification of ROS-active chemical constituents would transform our ability to design effective particulate emission control strategies. Broader impacts of this research will result from the reduction of the global burden of the diseases associated with ambient PM. These results will be disseminated to a broad audience of K-12 students and teachers through summer camps, as well as the public through online risk prediction modules to increase the scientific literacy of the Nation.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.