Nuclear accidents produce radioactive aerosol which contaminates the environment and travels long distances with wind, and these aerosol, due to their ionization, have an adverse impact on human health. A building is the first defence that people have to shield them from radioactive aerosol, but the behaviour of radioactive aerosol indoors is not understood well and more studies are needed. In the current work, test chamber experiments were conducted to calculate the deposition velocity of highly charged aerosol particles with both positive and negative polarity. When compared with earlier measurements, the results showed an increase in deposition velocity when aerosol particles were highly charged.