In this cross-sectional study data was obtained from reviewing the files of 1,594 patients who underwent bronchoscopy in Afzalipour Hospital during 2003-2007. These patients had various conditions ranging from chronic cough to abnormal findings on chest xray and hemoptysis and all underwent bronchoscopy due to the doctors’ orders. All cases consented to this study. Their bronchoscopy was done by experts who were skillful at diagnosing bronchial anthracosis. Bronchial anthracosis was characterized by dark pigmentations within airway mucosa found during bronchoscopy. Therefore, those with these dark pigmentations were considered as having bronchial anthracosis. All patients were anesthetized for bronchoscopy, and had oxygen support according to the related protocols
