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INVESTIGATION OF THE MECHANISMS LEADING TO RADON CONCENTRATIONS IN DWELLINGS

Objective

THIS RESEARCH PROJECT HAS TWO MAIN OBJECTIVES :
1. TO DEVELOP INSTRUMENTS FOR MEASUREMENTS OF RADON EXHALATION RATE AND TIME-AVERAGED RADON CONCENTRATIONS (TO BE USED FOR ROUTINE MEASUREMENTS OUTSIDE LABORATORY CONDITIONS).
2. TO OBTAIN DATA THAT MAY HELP TO GET A BETTER UNDERSTANDING OF THE PHYSICAL PHENOMENA THAT LEAD TO RADON CONCENTRATIONS INDOORS.
The development of a radon exhalation meter has successfully been concluded with a device that operates with a collection voltage of -2.5 kV on a foil in front of a surface barrier detector whilst the surrounding stainless steel cannister is at ground potential. From recent results, it is concluded that there is a discrepancy between calculations based on simple models and the data. This discrepancy is likely to be due to assumptions made on ventilation patterns.
AD(1) THE DEVELOPMENT OF RADON EXHALATION METER WILL START FROM AN EXISTING DESIGN, WHICH CONSISTS OF A HOOD TO BE PLACED OVER THE SURFACE OF E.G. AN EXISTING WALL. THE DESIGN PARAMETERS OF THIS INSTRUMENT WILL BE OPTIMIZED. SPECIAL ATTENTION WILL BE PAID TO SYSTEMATIC ERRORS DUE TO E.G. THE MODIFICATION IN THE RADON FLOW PATTERN INSIDE THE SAMPLE BY PUTTING A HOOD OVER A PART OF ITS SURFACE, BACK DIFFUSION, HUMIDITY, ETC.
FOR MEASUREMENTS OF TIME-AVERAGED RADON CONCENTRATIONS OVER RELATIVELY SHORT PERIODS (10-14 DAYS) ACTIVATED COAL CANNISTERS WILL BE USED. FOR THE DESIGN OF THESE CANNISTERS EXPERIENCES ELSWHERE WILL BE EVALUATED, AND, IF POSSIBLE, AN EXISTING DESIGN WILL BE COPIED AND/OR OPTIMIZED.
IT IS EXPECTED THAT THE FINAL DESIGN OF BOTH INSTRUMENTS IS FINISHED WITHIN 2 1/2 YEAR FROM THE START OF THE PROJECT.
AD(2)TO OBTAIN MORE INSIGHT IN THE TRANSPORT OF RADON FROM THE SOIL INTO DWELLINGS SEVERAL TYPES OF MEASUREMENTS WILL BE MADE. FOR THESE MEASUREMENTS EITHER THE INSTRUMENTS TO BE DEVELOPED OR THE PRESENTLY USED TRACK-ETCH METHOD WILL BE USED :
1. CONCENTRATION MEASUREMENTS IN THE CRAWL SPACE AND THE ROOMS ABOVE IT IN DWELLINGS WITH A KNOWN RELATIVELY HIGH OR LOW RADON CONCENTRATION. THESE MEASUREMENTS WILL START AS SOON AS POSSIBLE, AT FIRST WITH TRACK-ETCH DOSEMETERS, IN A LATER PHASE, IN CONJUNCTION WITH THE EXHALTATION RATE MEASUREMENTS (SEE 3), WITH ACTIVATED-COAL CANNISTERS.
2. EXHALTATION MEASUREMENTS ON SAMPLES OF BUILDING MATERIALS. THESE MEASUREMENTS WILL BE MADE DURING THE DEVELOPMENT OF THE EXHALATION RATE METER TO OBTAIN MORE INSIGHT IN THE TRANSPORT OF RADON IN THE SAMPLE, ESPECIALLY HOW IT IS INFLUENCED BY PLAVING THE HOOD OVER THE SAMPLE.
3. EXHALATION MEASUREMENTS IN CRAWL SPACES AND ROOMS OF THE DWELLINGS MENTIONNED UNDER 1. THESE MEASUREMENTS WILL START IN THE THIRD YEAR. THE RESULTS OF EXHALATION AND CONCENTRATIONS MEASUREMENTS WILL BE USED FOR MEDELLING OF THE RADON TRANSPORT IN DWELLINGS.
4. EXHALATION AND CONCENTRATION MEASUREMENTS IN THE OPEN AIR IN SELECTED AREAS WHERE THE OUTDOOR RADON CONCENTRATION HAS BEEN FOUND TO BE ABOVE OR BELOW AVERAGE. THESE MEASUREMENTS WILL BE COMBINED WITH GAMMA-SPECTROMETRIC MEASUREMENTS OF SOIL SAMPLES, AMONG OTHERS IN ORDER TO SEARCH FOR CORRELATIONS WITH THE EXHALATION FROM THE SOIL. PART OF THE MEASUREMENTS WILL BE MADE DURING THE FIRST TWO YEARS, BUT THE MAJOR PART WILL START IN THE THIRD YEAR.

Funding Scheme

CSC - Cost-sharing contracts

Coordinator

RIJKSUNIVERSITEIT GRONINGEN
Address
P.b.72
9700 AB Groningen
Netherlands