Project Summary The overall goal of this proposal is to characterize the WTC-related lower airway disorders, to investigate newly developed obesity-related imaging markers that may be associated with unfavorable disease expression and functional outcomes, and assess their interaction with WTC occupational exposure level. To that end, we will utilize the WTC Pulmonary Evaluation Unit Chest CT Imaging Archive, a large database with more than 3000 chest CT images on 1700 WTC workers that became operational in February 2016 and we established with our previous project. On that subcohort, we have also linked extensive datasets with disease symptoms, both pre-WTC and WTC-related occupational exposures, detailed pulmonary function and longitudinal spirometry measurements and weight trends, visual imaging classification and grading, and quantitative computer assisted method (QCAM) measurements of airway, and pulmonary parenchymal abnormalities. With our proposed research project renewal, we will continue to enrich most sources of data with periodic updates, in order to characterize the WTC-related lower airway diseases and their most important adverse prognostic risk factors, and evaluate their longitudinal trajectories.