Detailed behaviour of indoor radon daughters focused on effectiveness of an air cleaner

The effectiveness of an air cleaner was evaluated theoretically and experimentally in terms of lung dose reduction. The effect of the change of attachment rate, the enhancement of plateout and filtration rate of aerosols was introduced into a mass balance model for indoor radon daughters in steady state. Experiments were done in a large room at a ventilation rate of about 0.2.h-1 and the experimental results approximately agreed with theoretical ones from the improved model. The dose reduction rate was calculated using a lung dose model and the improved model. The calculation result showed that the dose reduction is only 50% of the untreated case if the aerosol filtration rate is 2.h-1. (author)