Indoor Radon Concentration Values Research Articles

Comparison of seasonal and yearly average indoor radon levels using CR-39 detectors

In order to assess the effect of long term exposure, CR-39 based radon dosimeters were exposed to indoor radon in the drawing rooms (living room) of 200 selected houses of the districts of Swabi, Mardan and Charsadda in the North West Frontier Province (NWFP) as well as in the Mohmand and Bajuar Agencies of the federally administered tribal areas (FATA), Pakistan. Dosimeters were exposed to the indoor radon during each season as well as throughout the year. From the measured indoor radon data it was observed that seasonal yearly average value were higher than that of the 12 months average indoor radon concentration values. The overall seasonal average was found to be 13% higher than that of the 12 months exposed CR-39 based dosimeters. However after the removal of the worst differences, seasonal average remains only 8 % higher than the 12 months averaged value.

Indoor Radon Survey in 120 Schools Situated in Four Districts of the Punjab Province — Pakistan

An indoor radon survey has been carried in 120 schools situated in four districts of the Punjab province, namely Attock, Chakwal, Jhelum, and Rawalpindi. In each season, a total of 360 CR-39-based radon detectors were installed in the selected schools. After exposure the detectors were etched in 6M NaOH at 80°C solution for 16 h and tracks densities, which are related to the radon concentration, were measured. Indoor radon concentration varied from 18 ± 7 to 168 ± 5 Bq·m-3 with an average value of 52 ± 9 Bq·m-3. High indoor radon concentration values were found in the summer season, whereas lower values were recorded in autumn season. The mean annual radon effective dose equivalent was estimated to be 0.49 mSv per year. Present indoor radon concentration values are higher than that of the world average value of 40 Bq·m-3, but lower than the action level recommended by the ICRP.

Indoor Radon Measurements in Dwellings of Some Areas of Upper Siwaliks, India using SSNTDs

The presence of radon and its decay products in the human environment are considered a potential health hazardous and measurement of them is important to assess the threat they might pose. Keeping this in view, indoor radon measurements were carried out in dwellings of different villages belonging to the upper Siwaliks of Kala Amb, Nahan, and Morni Hills, India using the LR-115 type II cellulose nitrate films in the bare mode. The annual average radon concentration in the studied area was measured in the range from 71.7 ± 21.0 to 421.7 ± 33.6 Bq·m-3. The levels of radon activity were found to be within the action level internationally recommended by ICRP. The average annual effective dose was found to vary from 1.22 to 7.20 mSv per year. Gamma ray activities were also measured in the dwellings of different villages to look for a possible correlation between indoor radon and gamma ray levels in the study area. The values of gamma ray activity were found to vary from 9.75 to 17.50 μR·h-1. The values of indoor radon concentration and gamma ray activity in the study area were compared with those from the adjoining nonradioactive areas of Punjab.

Application of a radon model to explain indoor radon levels in a Swedish house

Radon entry from soil into indoor air and its accumulation indoors depends on several parameters, the values of which normally depend on the specific characteristics of the site. The effect of a specific parameter is often difficult to explain from the result of indoor radon measurements only. The adaptation of the RAGENA (RAdon Generation, ENtry and Accumulation indoors) model to a Swedish house to characterise indoor radon levels and the relative importance of the different radon sources and entry mechanisms is presented. The building is a single-zone house with a naturally-ventilated crawl space in one part and a concrete floor in another part, leading to different radon levels in the two parts of the building. The soil under the house is moraine, which is relatively permeable to radon gas. The house is naturally-ventilated. The mean indoor radon concentration values measured with nuclear track detectors in the crawl-space and concrete parts of the house are respectively 75±30 and 200±80 Bq m −3. Results of the model adaptation to the house indicate that soil constitutes the most relevant radon source in both parts of the house. The radon concentration values predicted by the model indoors fall into the same range as the experimental results.

Environmental radioactivity: a case study in Himachal Pradesh, India

A radon survey has been carried out in the soil-gas and indoor air of some villages situated in the vicinity of areas known for uranium mineralisation in Himachal Pradesh (H.P.). Both active and passive techniques were used for radon monitoring inside the dwellings. The highest value, 75 400±2620 Bq m -3, of radon in soil-gas was found in the village of Samurkhurd. The mean values of indoor radon concentration for the village of Ramera, Asthota, and Galot were found to be 249±14, 200±16 and 161±13 Bq m -3, respectively. The average annual exposure doses due to radon and its daughter products to the inhabitants of these villages amount to 4.3±0.2, 3.4±0.3 and 2.8±0.2 mSv, respectively. Indoor radon levels are within the safe limits in most dwellings but call for mitigation of the radon health hazard in some others. A radon and helium survey of thermal springs in the Parbati and Kullu valleys of Himachal Himalaya was also carried out. The maximum values of radon (716.3 Bq l -1) and helium (90 ppm) activities were recorded in a thermal spring at Kasol in Parbati valley. In general, high radon and helium values are correlated with high uranium concentrations in the soil of the area in the environs of the thermal springs.

A review of radon pollution in buildings in Hong Kong

Indoor radon concentrations, radon emanation rates from building surfaces, radioactivity contents of building materials and the indoor gamma dose rates for Hong Kong are all in general higher than values obtained elsewhere. An interesting phenomenon has been noted that the values of indoor radon concentrations and radon emanation rates from building surfaces in Hong Kong tend to decrease with the age of the buildings, while the absorbed gamma dose rate remains about the same. The total average annual effective dose equivalent, and contribution from radon, thoron and their daughters, and that related to building materials will be shown. The number of radon-induced lung cancer deaths will also be discussed.

Measurement of indoor radon concentrations in Kuwait

Values of indoor radon concentrations averaged over one year has been determined in 60 dwellings mainly located in the coastal part of Kuwait. All dwellings were monitored using the track-etch method. The monitors used were replaced every 3 months to detect seasonal variations. Mean values of 41, 43.5, 42.5 and 41.3 Bq/m 3 were measured during autumn, winter, spring, and summer, respectively. The highest concentration in the survey, 103 Bq/m 3 was repeatedly measured during winter and spring, indicating lower ventilation rates. Separate data distributions for different floor levels shows mean Rn concentrations of 54.4, 48.4, 44, 41 and 31.3 Bq/m 3 in the basement and on the ground, first, second and third floors, respectively. The overall mean Rn concentration from the whole study was 41.3 Bq/m 3, which is equivalent to 5.58 mWL. Assuming an equilibrium factor of 0.5, and an occupancy factor of 0.8, the average exposure to the short-lived daughters of radon-222 of a member of Kuwait population is 0.228 WLM/yr. This is equal to an effective dose equivalent of 2.28 mSv, which is very close to the effective dose equivalent from natural radiation amounting to 2 mSv/yr. It is expected that further reduction in indoor ventilation, for the purpose of energy saving, will cause an increase in population radiation doses.