Evaluation of Radiation Exposure and Risk of Cancer Due to Radon in Dwellings Near Coal-Fired Thermal Power Plant

Radiation exposure from naturally occurring radon remains one of the most significant contributors to public dose from ionizing radiation, particularly in enclosed residential environments near thermal power plants. The concentration of radon inside a residence is significantly influenced by building characteristics, ventilation efficiency, and the surrounding environment. This research study estimated the annual effective dose rate (AEDR) and excess lifetime cancer risk (ELCR) in different types of dwellings surrounding the Simhadri National Thermal Power Corporation (NTPC) coal-fired power plant in Paravada, Visakhapatnam, Andhra Pradesh, India. The Smart RnDuo continuous radon monitor was used to measure radon concentrations inside 120 different houses constructed with Reinforced Cement Concrete (RCC), brick, or mud. The short-interval readings were averaged to derive representative daily concentrations, and annual effective doses were estimated based on internationally accepted exposure parameters. Across all dwelling categories, radon concentrations exceeded typical background levels, likely due to limited air circulation and the radon-retaining properties of certain building materials. Annual practical dose calculations revealed apparent differences among house types, with RCC structures showing the highest values, followed by brick and mud houses. This pattern reflects the elevated radon levels observed in more airtight constructions. The corresponding excess lifetime cancer risk, derived using standard risk coefficients, showed a similar trend, indicating comparatively higher risk for residents of RCC dwellings. Although all estimated doses remained within global safety guidelines, the observed variations reinforce the importance of building design and materials in regional exposure assessments. These findings provide valuable insights into environmental radiation studies in industrial zones and underscore the importance of dwelling type as a key determinant of indoor radon levels and associated health risks.