Exposure to second-hand smoke varied by smoking rate in the workplace and no-smoking policies. The purpose of this study was to estimate the status of second-hand smoke exposure by occupation through urine cotinine analysis in Busan, Ulsan, and Kyeongnam provinces.

Data was obtained from the National Institute of Environmental Research of Korea as 'The 2008 Korea National Survey for Environmental Pollutants in Human Body'. We selected 629 non-smokers who lived in Busan, Ulsan and Gyeongnam provinces. General and occupational characteristics were gathered using a structured questionnaire. Urine cotinine concentrations were analyzed by a gas chromatograph-mass selective detector. Statistical analysis was carried out using the Chi-square test, Student t-test and ANOVA.

The geometric mean (geometric standard deviation) of urine cotinine concentration was 17.11 (2.74) ng/ml. The urine cotinine concentration of the middle school graduate group (18.47 (2.86) ng/ml) was higher than the college graduate group (15.64 (2.60) ng/ml, p=0.212). Also, the cotinine concentration of current drinkers (18.98 (2.47) ng/ml) was higher than non-drinkers (16.15 (2.88) ng/ml, p=0.054). The proportion who smelled smoke was higher in workers (38.5%) than in non-workers (29.7%, p=0.02). Therefore, urine cotinine concentration was higher in workers (17.29 (2.66) ng/ml) than in non-workers (16.97 (2.81) ng/ml) but not at a statistically significant amount (p=0.826). In addition, cotinine concentration between the group who smelled smoke (20.45 (2.42) ng/ml) and the group who did not smelled smoke (15.53 (2.78) ng/ml) was significantly different (p=0.016) in workers but not in non-workers (17.08 (2.42) ng/ml vs 16.92 (2.98) ng/ml, p=0.942). According to the National Center for Health Statistics occupational categories in the US and the Korea Standard Classification of Occupations, the urine cotinine concentration of white collar workers such as technical workers and administrators, professional specialists, and managers was higher (18.01 (2.55) ng/ml) than that of blue collar workers such as plant and machine operators and assemblers, elementary occupations, and craft and related trades workers (15.36 (3.48) ng/ml).

The workplace is an important contributor to second-hand smoke exposure in Busan, Ulsan and Kyeongnam provinces. Unlike in advanced countries, where anti-smoking policies have been implemented, urine cotinine concentration in people in Busan, Ulsan and Kyeongnam provinces was higher in the white collar group than in the blue collar group. This result might be due to a higher indoor second-hand smoking rate of workplaces in these areas. Further studies are needed to evaluate the correlation between regional characteristics of industries, anti-smoking policies in the workplace, smoking rates and urine cotinine concentrations of workers.