Purpose: With the help of quantitative CT (QCT) imaging, it is able to identify minimal structural and functional changes induced by smoking with quantification of the airway, and inspiratory-expiratory image matching. However, information about airway QCT parameters and pulmonary dynamics of normal subjects, and the effect of subclinical smoking are insufficient. Thus, the purpose of the study is to evaluate the normal range of airway parameters and its predictive model, describe the volume distributions of normal subjects, and investigate the structural and functional airway, and parenchymal alterations in smokers with the derived normalization scheme. Materials and Methods: 222 non-smokers (97 male, 125 female) and 69 smokers (37 ex-smokers, 32 current smokers) with normal inspiratory/expiratory CTs and normal pulmonary function were included in the study. VIDA Apollo software was used for the analysis of airways and lung parenchyma, and with the image registration technique, the relative regional air volume changes (RRAVC) were further computed between inspiration and expiration. To control inter-subject variability, multiple linear regressions of tracheal wall thickness (WT), diameter (D), and luminal area (LA) were used for the normalization of airway parameters considering the effects of age, sex and height. Using this scheme, each airway parameter was normalized by individually predicted values, and normalized airway parameters from the 1st to 8th generation were compared between smokers and non-smokers. To understand normal pulmonary functional dynamics between inspiration and expiration, regional volume changes of nonsmoking subjects were analyzed using 3D visualization of acinar scale parenchymal units with RRAVC map, and volume distribution changes of smokers were compared with nonsmokers.Results: The normalization scheme helped to identify airway structural changes. While the luminal diameter and wall area continuously decreased along with whole generations(P0.05)on the proximal airways and it showed thinning on the distal airway (≥4th generation) in the smokers after normalization. RRAVC map demonstrated the increase of air volume change from apico-ventral to dorso-basal region in non-smokers, representing gravitational dependency in normal pulmonary dynamics. In comparison, the directionality of gravitational dependency of regional volume change tends to be against normality in smokers, and the coefficient of variation of RRAVC decreased in the whole lung of smokers (0.96 and 0.35, p