| Summary: | 碩士 === 國立高雄第一科技大學 === 環境與安全衛生工程研究所 === 100 === Many studies have confirmed that inhalation of nano-sized particles may pose adverse health effects. Therefore, many studies on the deposition of nano-sized particles in the human respiratory tract have been conducted in the past. However, most previous studies were mainly based on the replicate casts or human volunteers of Caucasians. Studies have shown that the geometric features of human nasal cavity vary with different ethnic groups and, thus, may cause difference in particle deposition efficiency. Accordingly, the present study measured the deposition efficiency of particles ranging from 14 to 500 nm under four different respiratory flow rates by using Caucasian and Taiwanese cast models. Additionally, 15 human subjects (9 males and 6 females) were recruited for the measurements of deposition efficiency to explore the potential difference between in vitro and in vivo studies. The results of this study showed that the deposition efficiency decreases with the increasing respiratory flow rates and that obtained from Taiwanese adults is higher than that of Caucasians. This may be resulted from the difference in the geometric structure between two ethnic groups. No significant difference was found in the deposition efficiency of male and female subjects. Moreover, particle deposition efficiency from in vitro and in vivo measurements was different. Some physiological features, such as mucus membrane and humidity in airways, may be responsible for the difference observed. An empirical equation was developed to characterize the nano-sized particle deposition efficiency of Taiwanese adults by employing diffusion parameter, airway shape factor of the nasal turbinate region (Sf) and parameter of nasal passage. This study suggests that more research efforts are needed to characterize the deposition efficiency of Taiwanese adults, which should be served as the basis for the risk assessment of inhalation dosage.
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