Exposure to Radon in Basement Spaces of Minnesota Homes

Abstract

A state-wide study of homes in Minnesota was conducted to determine bi-level radon measurements and occupancy patterns in homes with basements. Radon measurements were taken in the basement and the next level above the basement in 589 houses while residents reported the types and duration of activities performed in these two levels for one week. Analysis of the data shows that although radon levels are generally slightly higher in the basement than on thefirstfloor of the house, occupancy exposure measured in picocurie hours is greater on the first floor because of larger amounts of time spent on that level. Howevel; in ten percent of the homes, occupants’ exposure to radon, as measured by picoCurie hours, was higher in the basement. The activities that lead to higher basement exposure as compared to upper-level exposure to radon were: sleeping in the basement, sitting while watching TV or talking, and working in the basement. With the exception of using a forced-air furnace, construction characteristics of the house and mechanical systems did not affect basement exposure as compared to upper-level exposure to radon. The authors conclude that residents who use the basement for the activities noted above should test the level of radon in the basement.