For a given radon potential in the ground and a given building, the parameters affecting the indoor radon activity concentration (IRnAC) are indoor depressurization of a building and its air change rate. These parameters depend mainly on the building characteristics, such as airtightness, and on the nature and performances of the ventilation system. Ventilation to reduce radon was one of the most widely used, important, and effective means to reduce radon concentration in underground engineering.
Three ventilation strategies (no ventilation, continuous ventilation, and intermittent ventilation) were compared under various wind speeds and fresh air ratios. Under the same safe duration of radon concentration, when intermittent ventilation was operated with the same wind speed, the startup time was reduced by 79.4%, 86.0%, 90.8%, 92.8%, 91.25%, with compared with continuous ventilation. The higher the fresh air ratio, the lower the radon concentration limit, and the faster the dynamic equilibrium state of radon concentration will be reached.
Positive ventilation brings fresh air into a home, and dilutes the radon. The flow of air and radon from the ground may also be reduced. A positive ventilation system can be effective in homes with radon levels up to and around 500 Bq m-3.
Considering the comprehensive energy-saving benefits of the ventilation system, the appropriate intermittent ventilation plan should be made to meet radon reduction requirements in the range of low wind speed. If low wind speed was selected, there existed advantages of low ventilation noise and more comfortable, as well.
