A Test Chamber Investigation of the Effect of Charging on Aerosol Deposition on Indoor Surfaces

摘要

Exposure to radioactive aerosols of accidental origin is harmful to human health. Radioactive aerosols have an ability to self-charge due to ionization, and this influences their deposition behavior, but this effect has been rarely studied. In a test chamber study, the effect is investigated by using a corona unit to apply charges that are representative of the levels found on radioactive particles to three aerosol size distributions of 0.5 μm, 1.0 μm and 2.0 μm. Aerosol deposition velocities were calculated for each particle size, two chamber airflow values, three aerosol charge regimes (high positive, high negative, and no corona charging), and three interior wall surfaces (aluminum, wallpaper, polyethylene). The results show no significant difference between deposition velocities of charged aerosols of opposite polarities, but a difference of up to 72% between deposition velocities of corona-charged and uncharged aerosols. For all aerosol sizes and charge regimes, aerosol deposition was found to be enhanced to the greatest degree when the chamber walls were lined with polyethylene, with values found to be up to 4–8 times higher than those calculated in aluminum-walled chamber cases.