The influence of meteorological parameters on indoor radon in selected traditional Kenyan dwellings

Assessment of Seasonal Radon Concentration in Dwellings and Soils in Selected Areas in Ga East, Greater Accra Region of Ghana

Seasonal radon levels have been studied in dwellings and soils in selected areas in Ga East, Greater Accra Region of Ghana using LR-115-type II (SSNTDs). This study was conducted to determine the seasonal correlation between soil and dwelling radon concentrations. Detectors were exposed from January to March and April to June, for dry and wet seasons, respectively. Overall, indoor radon was 133.4 ± 6.7 Bqm-3 and 72.1 ± 3.6 Bqm -3 for wet and dry seasons. The estimated annual effective dose to the lung received by the occupants at Paraku Estate, Dome, and Kwabenya was 6.9 ± 0.4, 7.2 ± 0.5, and 9.8 ± 0.8 mSvy-1 for the wet season and 3.8 ± 0.2, 4.3 ± 0.2, and 4.6 ± 0.3 mSvy-1 for the dry season. On average, the soil radon concentration was found to be 0.96 ± 0.07 kBqm-3 and 2.24 ± 0.01 kBqm-3 for wet and dry seasons. To determine the correlation between soil and dwelling radon, a positive Pearson correlation coefficient value R = (0.74) and R = (0.66) was obtained representing the dry and wet seasons. To test the statistical significance between soil and dwelling radon, P < 0.05 was obtained, indicating a statically significant relationship between the two.

Residential radon exposure and seasonal variation in the countryside of southeastern Brazil

Poorly ventilated environments such as residences can accumulate radon gas to levels that are harmful to humans and thus produce a public health risk. To assess the risk from natural radiation due to indoor radon exposure, ²²²Rn measurements, using an alpha RAD7 detector, were conducted in Timóteo, Minas Gerais state, southeastern Brazil. Indoor radon concentrations, along with meteorological parameters, were measured every 2 h during both wet and dry seasons in 2017 and 2018. The mean concentration of indoor radon varied between 18.0 and 412.8 Bq m^-3, which corresponded to an effective annual dose of 1.2 and 7.6 mSv y^-1. Average radon concentrations were significantly higher during the winter dry season, and there was a strong positive correlation with humidity in both wet and dry season. Furthermore, concentrations showed an inverse correlation with atmospheric pressure, wind speed, air temperature, and solar radiation. The radon levels are generally above the limits recommended by international standards, meaning that mitigation measures are needed to improve air quality to reduce human exposure and risk. Finally, through the statistical analysis, it was possible to determine the differences and similarities between the sampling points concerning the geology of the place and the geographical location.

REVIEW OF RADON AND THORON RESEARCH IN KENYA: 1997-2017

Six research studies involving radon and thoron in Kenya were carried out between 1997 and 2007. The studies were mainly small scale and involved a few areas scattered across Nairobi, Rift Valley, Coast and Western regions. The results were captured in seven online journal articles. This paper relooks at the journal articles with the view of underscoring the high radon and thoron areas in Kenya, raising awareness on the sources and risks of radon isotopes in indoor environments and highlighting the need for more research on the isotopes in the country.

Radon and Thoron; Radioactive Gases Lurking in Earthen Houses in Rural Kenya

In this paper, documented studies on radon and thoron concentrations in earthen dwellings and ²³⁸U and ²³²Th concentrations in soil in Kenya are reviewed. High concentrations of the isotopes were recorded in the earthen dwellings despite being generally well ventilated. Mrima Hill in the Coast region recorded the highest thoron levels with a mean of 652 Bq m⁻³. Twenty five percent of dwellings had thoron concentration in excess of 1,000 Bq m⁻³. Notably high indoor radon levels were recorded in Taita Taveta also in the Coast region, and in Kenyatta University situated in Nairobi in the Central region of the country. Radon concentration in the Rift Valley region was found to be too low to contribute significantly to radiation exposure. Based on studies on the concentration of ²³⁸U and ²³²Th in soil, the Southwestern region of the country was anticipated to have elevated radon/thoron concentrations in earthen dwellings. Existing studies involving measurement of indoor radon and thoron, and ²²⁶Ra and ²³²Th in soil are relatively few and of a small scale. More extensive studies are therefore necessary not only to corroborate the risk projections but to also generate sufficient data to enable countrywide mapping of indoor radon/thoron risk-prone areas.