Fig. 3From: Impaired nuclear factor erythroid 2-related factor 2 expression increases apoptosis of airway epithelial cells in patients with chronic obstructive pulmonary disease due to cigarette smokingThe pH of exhaled breath condensate before and after smoking. The pH of exhaled breath condensate (EBC) before and after smoking in non-COPD smoking subjects. The pH of EBC was significantly decreased after smoking. Data were expressed as Mean ± SEMBack to article page