Particulate matter in air pollution is a significant global health threat and environmental concern linked to over 3million premature deaths annually. Some chemicals in particulate matter have the ability to cause high amounts of spontaneous mutations in DNA in both human cells and bacteria. While the consequences of such mutations in human cells are beginning to be understood (i.e., cancer), the role that such mutations play in bacteria is relatively unexplored. Interestingly, one mechanism through which bacteria can acquire the ability to resist antibiotic treatment is through spontaneous mutations, which may be driven by chemicals. Antibiotic resistant bacteria represent a significant medical challenge and have been associated with increased patient mortality and hospital costs. We propose to determine if commonly found chemicals in particulate matter can drive the evolution of antibiotic resistance in bacteria. To accomplish this goal, we will grow the bacterium Escherichia coli in the presence of different chemicals that are commonly found in particulate matter. We will then use standard mutagenicity tests to determine and quantify the ability of such chemicals to generate bacteria that are resistant to single, as well as multiple, common antibiotics. Using this data, we will then develop a mathematical model that aims to predict the occurrence of antibiotic resistant bacteria in the environment due to the interaction with particulate matter. Overall, results from our study may identify a significant, yet overlooked, mechanism by which bacteria can acquire antibiotic resistance and may help to identify a novel force of evolution in nature.