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

The deposition of radioactive aerosols, which are potentially harmful to human health, is influenced by their ability to self-charge via ionization. This relationship which has rarely been studied was investigated by corona-charging particles in three sizes (0.5 mu m, 1.0 mu m and 2.0 mu m) in a test chamber to levels representative of radioactive aerosols. The aerosol deposition velocities were calculated for each size fraction under a variety of conditions, which consisted of using two chamber airflow rates, three charging regimes (producing a strong positive charge, a strong negative charge, and no corona charge), and three interior wall surfaces (aluminum, wallpaper, and polyethylene). No significant difference in deposition velocity was detected between the charged aerosols, regardless of their polarity, but the deposition velocity of the charged aerosols exceeded that of the uncharged aerosols by as much as 72%. All of the size fractions, irrespective of the charging regime, exhibited the highest deposition rates when the chamber walls were lined with polyethylene, with values that were 4-8 times higher than those calculated for aluminum lining.