Survey of characteristics of exposure to mainstream cigarette smoke using discarded cigarette butts from Korean smokers.

Evaluating the characteristics of exposure to mainstream cigarette smoke is an essential field in tobacco research because of the large risk burden among smokers. Detailed evaluation of the complex factors pertaining to the exposure of smokers to mainstream cigarette smoke was attempted by analysis of discarded cigarette butts. A total of 5475 samples of discarded cigarette butts was collected to investigate the exposure characteristics in relation to Korean smokers. The basic physico-chemical characteristics of cigarettes, including the filter length, filter type, menthol addition, and nicotine and tar content, were determined and the manufacturer and cigarette size were identified. The tobacco-burned percentage (TBP)) and tar staining were used as physical markers, and actual human exposure to cigarette smoke was determined using the part filter method. Multiple linear regression analyses and generalized ordinal logistic regression analysis were conducted to identify the relationship between the socio-demographic factors and the physico-chemical characteristics of the cigarettes themselves and the exposure characteristics. Significant associations were observed between the TBP and age group, occupational group, manufacturer, tar staining, ISO tar content, and filter length. Increased odds of smoking with a heavier tar stain among Korean smokers were associated with blue collar workers vs. other workers, manufacturer B vs. other manufacturers, recess filter vs. other filter types, ISO tar content, and TBP. Finally, significant associations between the log-transformed human-smoked tar and nicotine yields and occupational group, the TBP, tar staining, and physico-chemical properties of cigarettes were found and were used to propose models for predicting the actual exposure to tar and nicotine. The proposed models account for 60-61% and 47-49% of the variance of human exposure to tar and nicotine, respectively. This analysis of discarded cigarette butts revealed that various factors, including socio-demographic factors such as age group and occupational group, as well as the physico-chemical properties of cigarette products such as the filter type and length, cigarette size, ISO tar and nicotine content, and mentholation, affect the characteristics of exposure of Korean smokers to mainstream cigarette smoke.