32 巻 (2017) 3 号 p. 151-156
To investigate the pulmonary toxicity of various atmospheric aerosols or airborne engineered nanomaterials, cell-based in vitro studies that use air-liquid interface exposure systems and in vivo inhalation exposure studies that use laboratory animals by either nose-only exposure system or whole body exposure system are commonly employed. In this report, the feature of each exposure system is demonstrated.
Taking the scale of each exposure system into consideration, a target concentration of the airborne particles in the exposure system that is equivalent to the dose in human lungs in the environment was estimated using deposition efficiency, target surface area, and ventilation. If an adult man during light exercise inhales 100-nm spherical particles at the concentration of 15 μg/m3, which is an environmental standard value of PM2.5 in Japan, the particle deposition rate in the lung is calculated to be 0.037 μg/m2/h. The concentrations that lead to the same deposition rate for cells in the air-liquid interface exposure system and rats in the inhalation exposure system are 1 μg/m3 and 4.6 μg/m3, respectively.