Small ion concentration in houses with enhanced radon concentration

The concentration of radon, small air ions, and aerosol particles were measured continuously in 16 Finnish dwellings. As expected, radon was found to be the major source for small ion generation in indoor air. A simple model for the relationship between ion concentration and radon concentration is tested. The parameters of the model are the ion production rate from radon and background radiation, the small ion recombination, the ion deposition on room surfaces, and the ion attachment rate to aerosol particles. The model is in reasonable agreement with measured, time-averaged values. The measured, particle-concentration data show peak values over ten times larger than the average. Consequently, momentary ion concentration cannot only be described as a function of radon concentration. Furthermore, large deviations from the model are found in momentary values due to short-time electric fields caused by human activities