This project is focused on determining the chemical fate of specific aerosol compound classes, including those from diesel exhaust (i.e., soot) and polycyclic aromatic hydrocarbons (PAHs). There are three major objectives of this research. The first is to develop sensitive methods for the determination of polar PAH derivatives. The second is to study the reaction mechanisms of particulate PAHs with nitrogen dioxide in the presence of oxidants. The third objective is to compare those reactions with the analogous reaction using diesel exhaust, under real world conditions. The mechanisms of atmospheric reactions are complex and involve participation of numerous species and factors. Since photolysis appears to be the fastest PAH decay process in the atmosphere, the effect of light will be investigated. Development of new analytical methods is necessary to ensure sensitive detection of nitro-PAH derivatives with different functional groups. Modern analytical methods including novel techniques such as hot pressurized water extraction, gas and/or liquid chromatography (GC and LC) with various mass spectrometric (MS) detectors (e.g., high resolution time of flight MS), will be used. The reaction pathways will be evaluated based on rate constants, the identification and quantification of the reacting PAHs, and formation of nitration and oxidation products with the goal of closing the mass balance. The reaction results obtained from the experiments with pure PAHs and artificially PAH-coated particulate matter (PM) will be compared to the PAH nitration in the diesel exhaust PM with naturally occurring PAHs. The results from the study are significant when studying atmospheric chemistry processes, determining the extent of air pollution, and consequently regulating the pollutants' emissions. Current health-oriented studies attribute adverse effects to species typically recognized in air PM (e.g., metals and non-polar organics). In contrast, more detailed knowledge on polar species such as nitro-PAH derivatives is needed. The principal investigator plans activities addressing audiences at four different stages of education. Local high school students will be targeted through an air pollution workshop with the aim to boost the undergraduate enrollment in science classes and to help enhance the science education in local high schools. Freshmen and sophomore students from tribal colleges will participate in a summer research experience program providing direct exposure to the university research environment and establishing a pathway towards transfer into science programs. Middle school 5th-8th graders will be introduced to sustainable energy and related air pollution issues by building modules into a successful university- middle-school program. Undergraduate chemistry students will be exposed to modern chromatographic and MS techniques with a focus on air pollution within a redesigned instrumental analysis laboratory course targeting an increase in the enrollment and interest in analytical chemistry graduate studies. Finally, a group of graduate and undergraduate students, and a postdoctoral research fellow participating in the project will be influenced by a comprehensive research experience. The participating researchers will also gain educational experience while presenting their project results. Their presentations in the redesigned lab course and workshop will help students involved relate their experiences to advanced research in atmospheric chemistry.
