Effect of Ventilation Type on Radon Concentration at Places of Work

Abstract

Abstract Indoor radon (222Rn) concentrations were measured at 76 child care facilities and 36 schools in southern Finland. The buildings had three different types of ventilation systems: mechanical air supply and exhaust, mechanical exhaust, and natural ventilation, the first being most common. The effect of the ventilation type on the long-term radon concentration was studied in child care facilities. The radon concentrations were highest in the naturally ventilated buildings. The mechanical air supply and exhaust system maintained the lowest values in cold wintertime. In school buildings both the long-term radon concentration and short-term radon and daughter concentrations were measured. The correlation of the ventilation type and the radon concentration was not obvious in this group of measurements. But the radon concentrations and the equilibrium factors were highest in buildings with natural ventilation. Radon concentrations were generally lower during the working hours than during the one-month period, as expected.