Risk assessment and estimation of controlling safe distance for exposure to particulate matter from outdoor secondhand tobacco smoke

Abstract

Exposure to secondhand smoke (SHS), and its intake through inhalation, is a major reason for premature death. Therefore, it is essential to determine safe distances from the smoking source to control passive exposure to tobacco smoke by carrying out appropriate risk assessments. In this study, we investigated the emission and diffusion of particulate matter (PM10 and PM2.5), along with black carbon, from smoking different kinds of cigarettes, including conventional cigarettes, heating e-cigarettes, and liquid e-cigarettes, using computational fluid dynamics (CFD) analysis. The results were used to evaluate the risk of passive exposure to PM10 and PM2.5 at different distances from the smoker for the general population and 6-10-year-old children. Results of the risk analysis were compared by considering the accumulated mortality ratio caused by cancer, and circulatory and respiratory systems disorders as the baseline risk for these two population groups. Results show that normalized emitted aerosol from vaping liquid e-cigarettes is higher than when other types of cigarettes are used. We also detected the emission of black carbon, which has a statistically significant correlation with the emission of particulate matter. Our risk assessment analysis suggests a safe distance of 10 m from smokers for the general population as well as a greater distance for children.