This study explored the respiratory deposition characteristics of sub-micron particles (particulate matter (PM 1 )) emitted from cigarettes, e-cigarettes and incense to assess the health impacts of indoor PM 1 exposure. A smoke chamber was used to simulate the emission process, and the particle size distributions were determined by employing a universal scanning mobility particle sizer. The highest number concentration of PM 1 was observed in cigarette smoke, followed by incense and e-cigarette smoke. The size distributions of cigarette and incense smoke exhibited a unimodal distribution, while the e-cigarette smoke exhibited a bimodal distribution. Furthermore, a multiple-path particle deposition model was used to estimate the deposition fractions of PM 1 emitted from various smoke sources. Results indicated that the total deposition fraction of PM 1 from e-cigarette smoke in the respiratory tract (24.4%) was significantly greater than those of cigarette smoke (15.8%) and incense smoke (17.3%). PM 1 deposition fractions followed the order of pulmonary > tracheobronchial > oral cavity, with the right lower lung lobe showing higher deposition. Additionally, the highest particle deposition fraction was observed in 9-year-old children. These findings highlight the urgent need for stricter indoor air pollution control measures to protect public health, especially amongst sensitive populations like children and infants.
Chen et al. (Tue,) studied this question.