Chronic exposure to biomass smoke (BS) can significantly compromise pulmonary function and lead to chronic obstructive pulmonary disease (COPD). To determine whether BS exposure induces a unique phenotype of COPD from an early stage, with different physiopathological features compared with COPD associated with smoking (cigarette-smoke (CS) COPD), we assessed the physiopathology of early COPD associated with BS exposure (BS COPD) by incorporating spirometry, high-resolution computed tomography (HRCT) imaging, bronchoscopy and pathological examinations.