Dr. Rafael E de la Hoz and colleagues have performed standardized and computer-assisted readings of all chest CT scans received by WTC workers and volunteers at the Mount Sinai Medical Center between 2003 and 2016. The clinical team sought to assess all findings suggestive of airway, interstitial, and neoplastic disease in a systematic way, and correlate those findings with clinical, functional, and exposure indicators. The study team's research will also involve analyses of longitudinal imaging and functional trends, and characterization of the WTC related lower airway diseases and their risk factors, with a focus on obesity-related imaging markers. The study team also plans to characterize the transitions into chronic obstructive pulmonary disease (COPD) among these workers. The researchers also propose to test the use of added respiratory surveillance tools and explore functional markers of disease progression, explore alternate methods to investigate longitudinal functional trajectories, and novel spirometry calibration methods that might facilitate the implementation of spirometry in nonspecialized settings.