The purpose of this study is to examine exposure to secondhand smoke in respect to people’s pedestrian movement throughout the neighborhoods in Morningside Heights, Bloomingdale, and the Manhattan Valley and the Columbia campus. This study seeks to examine the exposure of individuals to secondhand smoke throughout the neighborhoods adjacent to Avery Hall and Columbia University. This corridor receives a large amount of pedestrian traffic every day as people are constantly walking in the Morningside Heights, Bloomingdale, and the Manhattan Valley neighborhoods both to walk toward Columbia University, away from Columbia University, and toward the mixed use corridors in the Bloomingdale and the Manhattan Valley neighborhoods. We expected to see high smoker concentrations in front of bars, delis, restaurants, and smoke shops. We also expected people to be smoking at the same spots, as detected by cigarette butts on the ground. We also expected the secondhand smoke radius to be large enough to measure.