Cigarette smoking is the major cause of chronic obstructive pulmonary disease (COPD), the 4th cause of mortality in the US. Central to COPD pathogenesis is "ciliopathy", dysfunction of the airway ciliated cells that mediate transport of mucus to remove inhaled pathogens. The focus of this study is to carry out metabolic profiling of banked biologic samples and assess the hypothesis that COPD is associated with a unique metabolome in serum and lung epithelial lining fluid, and that subsets of the COPD metabolome are linked to the ciliopathy of COPD.