Detection properties of a measuring system for a continuous soil radon concentrations monitoring.

The continual soil-gas radon concentration measurements are absolutely crucial for a reliable assessment of radon entry characteristics into the indoor building environment. For this purpose, a new detection system (a continuous monitor RM-3) was developed and tested. The detection principle of the monitoring device is based on an airflow ionisation chamber operating in a current mode. A comprehensive series of testing and calibration experiments have been carried out in a laboratory environment. An output signal of the device caused by the radon concentration in a sensitive detection volume significantly depends on a detector ventilation rate, the gas flow rate through the ionisation chamber. A set of calibration experiments was accomplished with the artificial radon source application and close circuit experimental arrangements. The system detection properties including applied experimental conditions and key results of pilot in situ measurements are reported in detail.

Statistical model of quality of radon measurements using electret ion chamber detectors.

This paper presents a statistical model for estimating probability, which states that a quality of radon measurements using the electret ion chamber system RM-1 will be accurate. The quality of the electret measurement was modelled as a ratio between the reference radon concentration and values measured under real conditions with varied levels of indoor radon concentration and microclimate indoor conditions. It was stated that the accuracy tolerance of measured values is 20 % of the given reference value. To estimate the uncertainty of the statistical model, the exact confidence limits for the estimated probabilities are computed. The statistical model was confirmed by an independent set of measurements. Moreover, the effect of absolute humidity on the quality estimation of electret detectors are also statistically analysed and discussed. The results of the statistical model confirm that the electret system is robust and suitable for estimation of radon concentration.

Significance of independent radon entry rate and air exchange rate assessment for the purpose of radon mitigation effectiveness proper evaluation: case studies.

Two new single-family houses identified as insufficient with regard to existing radon barrier efficiency, have been selected for further examination. A complex set of radon diagnosis procedures has been applied in order to localise and quantify radon entry pathways into the indoor environment. Independent assessment of radon entry rate and air exchange rate has been carried out using the continuous indoor radon measurement and a specific tracer gas application. Simultaneous assessment of these key determining factors has turned out to be absolutely crucial in the context of major cause identification of elevated indoor radon concentration.