Assessment of Radon Concentration, Annual Effective Dose, and Excess Lifetime Cancer Risk in Homes Constructed with Limestone, Fired Clay Bricks, and Concrete Blocks in Al-Muthanna Province

Abstract: This study measured radon gas concentrations in three types of houses in Al-Muthanna Governorate, located in southwestern Iraq, which were built using the most common building materials in the governorate: concrete blocks, fired clay bricks, and limestone. Houses were randomly selected (20) samples for each house type to ensure comprehensive representation and determine the effect of building material type on indoor radon concentration, which helps in assessing the health risks associated with long-term exposure to this gas. It also contributes to guiding future policies towards the use of safer building materials to enhance indoor air quality and population safety. In this study, an Airthings Radon Portable Detector was used to measure radon concentrations over three consecutive days. The device was placed in living rooms at a height ranging from 60 to 100 cm above the ground, ensuring that windows and doors were closed to prevent air drafts and to provide accurate measurements. The results showed that the average radon concentration was highest in houses built of limestone (24 Bq/m³), followed by houses constructed of concrete blocks (21 Bq/m³), and lowest in houses built of fired clay bricks (16.25 Bq/m³). In terms of the estimated annual effective dose, it was higher in limestone houses (0.605 𝒎𝑺𝒗.𝒚 −𝟏 ), compared to concrete block houses (0.530 𝒎𝑺𝒗.𝒚 −𝟏 ) and fired clay brick houses (0.410 𝒎𝑺𝒗.𝒚 −𝟏 ). and The ELCR resulting from radon exposure was found to be higher in limestone houses (0.238%) and lower in fired clay brick houses (0.161%), suggesting that fired clay brick may be the most suitable choice in terms of radiation safety. Despite this disparity, all values remained within the safe limits and percentages recommended by the WHO and UNSCEAR. It can be concluded that the measured radon concentrations are within acceptable limits, indicating no radioactive hazard. The study reveals that the type of building material affects indoor radon concentrations, and the geological nature of limestone likely contributes to higher emissions. Accordingly, the study recommends using low-radonemitting building materials and periodically monitoring gas levels to maintain indoor air quality and reduce long-term health risks.