Collection and Analysis of Chemical Reaction Products When Protein Samples Are Exposed to Denver Urban Air

An increase in seasonal allergies has been observed over the years affecting human health. Environmental factors and atmospheric pollutants can induce chemical modifications of airborne allergens, increase oxidative stress in the human body, and skew the immune system toward allergic reactions [2]. Laboratory studies exposing certain allergenic proteins to simulated gas-phase air pollution have shown that the proteins undergo chemical modifications that make them even more allergenic. In continuation of work done by former student Dr. Rachel Davey, my project has been to collect and analyze protein samples exposed to ambient Denver air at two field-site locations. The goal of the study has been to further understand the types of processes that occur during the nitration of exposed tyrosine amino acid residues when exposed to ozone (O3) and nitrogen dioxide (NO2). Specifically, the work set out to extend the previous results by comparing the extent of both the nitration and oligomerization reactions to explore a hypothesis that Dr. Davey proposed. Two samples per field site were collected at the two sites over 9 months and analyzed in the lab.

Through the experimental process, significant effort was needed to verify experimental steps, including the filter extraction efficiency and aspects of the analysis process. Furthermore, the project involved maintenance tasks, including the calibration of scientific instruments such as the ultraviolet spectroscopy and Gast pump. These activities were crucial to ensure the accuracy and reliability of the data collected throughout the experimental process. More recently, the first field samples were analyzed using high performance liquid chromatography. My work has been an important component of a multi-year experimental project that will help provide better understanding of the role that these reactions play on the surfaces of protein-containing airborne bioaerosols in inducing health effects in urban areas.