Radon Concentration In Houses Research Articles

Indoor Radon Measurements in Anomalous Sites of Piedmont, Italy

Abstract This laboratory, responsible for the monitoring of radon environmental pollution in the Piedmont Region (total area 25,400 km2, population (4.5 million), decided to promote surveys in areas where the presence of high radon concentrations is expected. Indoor radon concentrations in houses in the village of Peveragno (CN) were studied. Peveragno is a small centre (400 inhabitants) in the western Alps where there was a uranium mine until the 1960s and where many water sources and wells with a high radon content were found. The measurement techniques employed were based on Kodak LR-115 type II etched track detectors. The number of houses monitored (during summer 1992) was 86, distributed throughout the Peveragno municipality. Usually, two dosimeters were employed for each house, one in the lower floor, the other in the higher. In special cases cellars were also measured. The radon content in public water supplies was also measured. High radon levels were found in many cases: about 13% of all houses monitored showed concentrations above the Reference Level of 400 Bq.m-3, with a maximum of over 24000 Bq.m-3. The results are presented and discussed.

Indoor Radon Measurements in Anomalous Sites of Piedmont, Italy

This laboratory, responsible for the monitoring of radon environmental pollution in the Piedmont Region (total area 25,400 km2, population (4.5 million), decided to promote surveys in areas where the presence of high radon concentrations is expected. Indoor radon concentrations in houses in the village of Peveragno (CN) were studied. Peveragno is a small centre (400 inhabitants) in the western Alps where there was a uranium mine until the 1960s and where many water sources and wells with a high radon content were found. The measurement techniques employed were based on Kodak LR-115 type II etched track detectors. The number of houses monitored (during summer 1992) was 86, distributed throughout the Peveragno municipality. Usually, two dosimeters were employed for each house, one in the lower floor, the other in the higher. In special cases cellars were also measured. The radon content in public water supplies was also measured. High radon levels were found in many cases: about 13% of all houses monitored showed concentrations above the Reference Level of 400 Bq.m-3, with a maximum of over 24000 Bq.m-3. The results are presented and discussed.

Influence of Shallow Mine-Workings on the Radon Concentrations in Houses: A Problem of Old Mining Regions

In some regions of the German New Federal Lands, residues from early mining characterise the radiological situation and can also influence the radon concentration in buildings. Construction on waste rock with increased radium concentration, the use of waste rock as building material and construction above shallow mine shafts and adits are important in this connection. In Saxony, for instance, one has to reckon with probably hundreds of buildings that may be influenced by radon from shallow mine workings. Very short-term changes of radon concentrations in buildings over several orders of magnitude was well as their close temporal correlation with the underground airflow clearly indicate influences from underground. In Schneeberg and Schlema, fluctuations of radon concentration in buildings of several 10,000 Bq.m-3 within one hour were observed. In Schneeberg, the old mine was ventilated artificially by installing a ventilator with an output volume of 500 m3min-1. Thus the radon concentration in buildings of the central city area has been reduced. In Schlema, the radon rich shafts of early mining are ventilated at present by the still active ventilation system of the suspended uranium ore mining. In 1992, during the first six months, 4.5 x 109 m3 of mine air with a radon activity of 6.3 x 1014Bq were extracted from the mine. If the mine ventilators are switched off, radon concentration in buildings over mine shaft increases sharply by two orders of magnitude.

High indoor radon variations and the thermal behavior of eskers.

Measurements of indoor radon concentrations in houses built on the Pispala esker in the city of Tampere were taken. The objective was to find connections between indoor radon concentrations, esker topography, and meteorological factors. The results show that not only the permeable soil but also subterranean air-flows in the esker strongly affect the indoor radon concentrations. The difference in temperature between the soil air inside the esker and the outdoor air compels the subterranean air to stream between the upper and lower esker areas. In winter, the radon concentrations are amplified in the upper esker areas where air flows out from the esker. In summer, concentrations are amplified in certain slope zones. In addition, wind direction affects the soil air and indoor radon concentrations when hitting the slopes at right angles. Winter-summer concentration ratios are typically in the range of 3-20 in areas with amplified winter concentration, and 0.1-0.5 in areas with amplified summer concentrations. A combination of winter and summer measurements provides the best basis for making mitigation decisions. On eskers special attention must be paid to building technology because of radon.

Impact of subslab ventilation technique on residential ventilation rate and energy costs

Radon is the largest source of risk to human health caused by an indoor pollutant in the industrial countries. Subslab ventilation (SSV) is one of the most effective and common methods of reducing indoor radon concentrations in houses with a basement. In this paper, the impact of SSV on the air exchange rate is quantified, through numerical modeling of a prototype house with basement for a range of permeabilities of soil and subslab aggregate and various sizes of the cracks in the basement floor. We show that a SSV system can increase the air exchange rate by as much as a factor of 4.5. Then the energy and capital costs of a subslab depressurization (SSD) system are compared with those of direct ventilation of the basement which is required to lower the indoor radon concentration to an acceptable level for a Chicago climate. We show that (1) an exhaust ventilation cannot significantly reduce the indoor radon concentration and may even increase it, and (2) a balanced ventilation with heat recovery is only effective for low premitigation radon concentrations. However, both SSV and balanced ventilation systems are probably too expensive to be recommended in houses with low premitigation radon concentrations. A SSD system is the most cost-effective technique for reduction of high radon concentrations.

Airborne 222Rn Concentration in Cypriot Houses

Studies from a pilot survey in 89 houses in Cyprus show that the arithmetic mean for the housing stock is about 7 Bq m-3 and the annual effective dose equivalent to the population from radon progeny is < 330 microSv y-1. Four houses have values > 30 Bq m-3, corresponding to two standard deviations from the mean value. The highest value recorded was 78 Bq m-3. These results are considerably lower than those of other countries reported in the literature. Radon concentrations in houses is correlated to the local geology. The highest concentrations are in houses built on Chalk formations with an average value of 9.29 Bq m-3 (standard deviation 19.69 Bq m-3). The lowest concentrations are in houses built on Olivine Basalt formations with an average value of 0.50 Bq m-3 (standard deviation 0.80 Bq m-3).

Radon hazards associated with outcrops of Ohio Shale in Ohio

The indoor (basement) radon concentrations and the uranium, organic carbon, and radon contents of samples from the underlying Ohio Shale (Upper Devonian) were investigated in six approximately 100 square kilometer areas of Ashtabula, Cuyahoga, Erie-Huron, Franklin, Pike, and Logan counties. The thickness and lithology of the sediment overburden above the Ohio Shale in these areas also was investigated. Results show that the amount of radon gas emanating from the Ohio Shale is a direct function of the uranium concentration in this geologic unit and that the uranium itself is ultimately controlled by the amount of organic matter. Uranium, organic matter (as measured by total organic carbon), and radon in the Ohio Shale outcrops all increase in a westward direction across Ohio. Similarly, the indoor radon concentration in houses increases from east to west across the state. Where the average thickness of the sediment overburden exceeds 27 m (Franklin and Logan counties), much of the radon in houses may be derived from Ohio Shale clasts in the glacial till. In other areas where the average overburden thickness is 6 m or less (Ashtabula, Cuyahoga, Erie-Huron, and Pike counties), the indoor radon levels appear to be directly controlled by emanations from the underlying Ohio Shale bedrock.

Radon Concentration in Houses in the Vicinity of Topeka, Kansas

Measurements of the radioactive gas radon within houses located in the immediate vicinity of Topeka, Kansas, gave a mean value of 3.6 pCi/liter with a standard deviation of 4.3 and n = 95. The distribution of radon concentration peaked sharply between I and 2 pCi/liter. Four values were above 2 standard deviations from the mean.

Application of nuclear track detectors for radon related measurements

Abstract Personal experience in the application of nuclear track detectors for radon related measurements are discussed. The paper summarizes previously published work. The “Can Technique” used for measuring radon emanation from building materials, walls and soil. “Working Level Monitor” used for measuring Working levels of radon daughters in houses in a short period. “Passive radon dosimeters” used to measure radon levels in houses for long term (few months) periods. Application of nuclear track detectors for measuring the radon daughters plate-out on surfaces of mixing fan blades and walls are discussed. Uranium content of some wall papers were found to be 6 ppm. Variation of radon progeny concentration in same room is measured and supported by another study through Gas Chromatograh measurements. Independent of radon concentration on room,s level in high- rise buildings is concluded. Effect of Sub-floor radon emanation on radon concentration in houses is depend on wether there is sub-floor ventilation or not.

Automated system for measuring air-exchange rate and radon concentration in houses.

We have developed an automated system for continuously measuring the air-exchange rate and 222Rn (radon) concentration in an occupied residence. The air-exchange rate is measured over 90-min intervals by tracer gas decay using sulfur hexafluoride as the tracer gas. The radon concentration is measured over 3-hr intervals using a flow-through scintillation cell. Temperatures at up to seven points are measured every half hour. A microcomputer system controls the measurements, performs preliminary data analysis, and logs the data and the results. Continuous measurement of ventilation rate and radon concentration permits the effective radon source magnitude to be calculated as a function of time. The first field application of this system was a study in Rochester, NY, of residential air-exchange rates and indoor air quality. For the 8 houses monitored, the mean values over 4- to 14-day periods ranged from less than 0.2 to 2.2 pCi l-1 for radon, from 0.22 to 1.16 hr-1 for air-exchange rate and from less than 0.05 to 0.75 pCi l-1 hr-1 for radon source magnitude.