We propose to add a collection of buccal cells to a school-based cohort of 7th graders in Wuhan, a large industrial city in China. The cohort study is being conducted by the Wuhan Public Health and Anti-Epidemic Station (Li Yan MD, director and principal investigator). The cohort study is designed to look at several outcomes. One is initiation of smoking. The second is respiratory health in relation to active and passive smoking and other environmental exposures that are prevalent in Wuhan. The respiratory outcomes include changes in pulmonary function, asthma and other respiratory symptoms. Collection of buccal cells is a noninvasive method of obtaining DNA. The addition of a genetic sample will enable us to examine candidate gene associations for asthma and childhood respiratory illness within an interesting and well-characterized Chinese population. In addition, it provides the capability to examine gene environment interaction with respect to common environmental exposures in Wuhan. The ability to examine gene-environment interaction can help to identify relatively subtle effects of pollutants such as environmental tobacco smoke which is becoming a very common exposure due to the major increase in smoking among Chinese men. Other exposures of interest in Wuhan are indoor coal burning and high ambient exposures to particules, ozone and nitrogen oxides. The proposed study has been approved by the human subjects committee of the Wuhan Public Health and Anti-Epidemic Station.