OBJECTIVES: To evaluate the association of urinary 2-naphthol level and air pollution caused by exposure to smoking, traffic and residential factors. METHODS: The study subjects consisted of 300 university students in Incheon. The questionnaires concerning subject characteristics, smoking amount, traffic, distance between housing and main road, heating and cooking fuel including urinary cotinine levels were checked. RESULTS: There was not any significant association between urinary 2-naphthol level and age, sex, body mass index, distance from mainroad, traffic, heating and cooking fuel. The urinary 2-naphthol level was higher in smokers or high urinary cotinine level group(p=0.0001)than in nonsmokers or low urinary cotinine group. After adjusting for age, sex, and body mass index in the basic model, the 2-naphthol level was also higher in the smokers or high urinary cotinine level group, too(p<0.0005). The model included both traffic and residential variables and it had a good fitness as compared to other models. CONCLUSIONS: It has been known that as one of PAH metabolites, urinary 2-naphthol is a respiration-selective biological marker. We showed that tabacco smoking has a much stronger effects on urinary 2-naphthol levels than when subjects were exposed to air pollution, such as traffic, and other residential factors at the same time.