Figure 3

(a) Radon concentrations in living rooms using different building materials. The radon concentration ranged from 33 to 76 Bq m⁻³ with a mean of 49 Bq m⁻³ (represented by the blue long dash line). The red short dashed line represents the worldwide-average of 40 Bq m⁻³. (b) Radon concentrations in bedrooms using different building materials. The radon concentrations ranged from 29 to 101 Bq m⁻³ with a mean of 56 Bq m⁻³ (represented by the blue long dash line). The red short dashed line represents the worldwide-average of 40 Bq m⁻³. (c) A plot of radon concentrations in living rooms and (d) in bedrooms that located on the ground floor and second floor, and the number of the windows in the room.