Indoor Radon (222 Rn) Levels In Coastal And Rift Valley Regions Of Kenya

Abstract

Measurements of indoor radon levels by electret technique in Coastal and Rift Valley Region of Kenya are reported. The results indicate a large variation in the concentrations (5 - 704 Bq rn') and that remedial action is necessary in some dwellings.

The geological formations and the manner in which the houses have been constructed have a bearing on these radon levels. Most of the houses were made of mud bricks. The radon levels (43-704Bq-3) were found higher in Taita and Taveta regions.

This is because the house construction procedures in these regions minimize the natural ventilation. This is in contrast with Soi region where temperatures range 24 to 32°C throughout the year and the houses had more natural ventilation with radon concentration levels being less than 1 00Bqm-3.

This was a factor of three lower compared to the levels of 222Rn (mean = 199 Bq-3) in the stone houses at Soi because they were more air tight than the mud houses. The annual effective dose varied from 0.4 to 3.6 mSv yolo