indoor radon in larijan buildings affected by geological characteristics

Background: the decay of uranium and thorium is the primary source of radon emissions, a radioactive gas. the transfer and accumulation of this gas indoors pose serious health risks. methods: this study investigated indoor radon concentrations in buildings located in areas with different geological characteristics. thirty-six buildings were examined across three locations in larijan, iran, with samples collected from living rooms and bedrooms over a three-month period.results: the average radon concentrations in bedrooms and living rooms were 114.40 bq/m3 and 128.35 bq/m3, respectively. indoor radon levels in buildings near hot springs were 24.66% higher than those in buildings close to, and 45.31% higher than those in buildings far from, hot springs. seasonal variation was also observed: the average concentration in winter was 112.05 bq/m3, compared with 130.89 bq/m³ in summer. these findings indicate that both climatic and geological conditions significantly influence indoor radon levels. conclusion: since radon concentrations in most buildings exceeded the world health organization (who) guideline of 100 bq/m3, implementing exposure control programs in residential buildings is essential.