The effect of a fan in reducing the concentration of the radon daughters inside a room by plate-out to the surface of the wall using plastic α-detectors

Solid state nuclear track detectors (CR-39) have been used to study the turbulence effect in a room contaminated by a radium compound giving a radon activity of approximately 5 pci 1-1. The room is in a basement, without windows and is normally closed and unused. The number of radon daughters deposited per unit area on the two sides of the blades of the fan was more than those plated out per unit area on the wall surfaces. However, the total surface area of the fan blades was only 0.2% of the surface area of the walls. The activity on the blades was calculated as reducing the level inside the room by approximately 1%, while the main decrease in the airborne activity was due to the plate-out on the surface of the room walls. (U.K.)