Ciliated epithelial cell damage is due to infectious factors causing airway mucosal damage and chronic inflammation. Viral infections with influenza virus, rhinovirus, adenovirus and respiratory syncytial virus are common. Bacteria are often secondary to viral infections, and common pathogens are Streptococcus pneumoniae, Haemophilus influenzae, Catamorax and Staphylococcus. There may also be harmful gases and harmful particles such as cigarettes, smoke, dust, and irritant gases. These can damage airway epithelial cells, leading to a decrease in airway purification function. They also stimulate submucosal receptors, parasympathetic hyperfunction, which causes contraction of airway smooth muscle, hypersecretion of glands, and increased airway resistance. There are also autoimmune, age and climate related. Examination of cilia epithelial cell injury and detachment: 1. Bronchoscopy Bronchoscopy is suitable for doing observation of lung lobes, segments and subsegments of bronchial lesions, biopsy sampling, bacteriological and cytological examination, with TV system for photography, demonstration and dynamic recording. This bronchoscope is attached with biopsy sampling mechanism, which can help to detect early lesions and carry out in vivo surgical procedures such as polyp removal, and is a good precision instrument for bronchial and lung disease research, post-operative examination, etc. 2.Sputum examination is used to assist in the diagnosis of certain respiratory system diseases, such as bronchial asthma, bronchiectasis, chronic bronchitis, etc., to confirm the diagnosis of certain respiratory system diseases, such as pulmonary tuberculosis, lung cancer, pulmonary schistosomiasis, etc., and to observe the efficacy and prognosis, such as sputum goodness and trait changes, etc.