Applied Journal of Physical Science

This study evaluates indoor radon concentration levels in Port Harcourt Metropolis using measurements from three locations: Rivers State University campus (RSU), Rumughalu, and Oyigbo. The Corentium Airthings Digital Radon Detector was used to assess radon levels in ventilated and non-ventilated spaces, with Global Positioning System (GPS) support for accurate location referencing. Ten sampling points were assessed per location. At the RSU campus, non-ventilated areas recorded concentrations ranging from 3 to 33 Bq/m³, with an average of 17.4 ± 2.99 Bq/m³, while ventilated areas averaged 9.0 ± 1.33 Bq/m³. In Rumughalu, a densely populated industrial area, non-ventilated spaces recorded significantly elevated levels (73 – 322 Bq/m³), averaging 118.8 ± 23.4 Bq/m³, whereas ventilated spaces averaged 13.4 ± 1.19 Bq/m³. Oyigbo recorded 81.2 ± 1.79 Bq/m³ in non-ventilated areas and 17.5 ± 2.43 Bq/m³ in ventilated ones. The Annual Effective Dose Rate (AEDR) in Rumughalu’s non-ventilated areas was 0.57 ± 0.11 mSv/year, remaining below the International Commission on Radiological Protection (ICRP) recommended limit of 1.0 mSv/year. Excess Lifetime Cancer Risk (ELCR) values were location-specific: RSU (0.29 ± 0.05) × 10⁻³, Rumughalu (2.39 ± 0.47) × 10⁻³, and Oyigbo (1.36 ± 0.03) × 10⁻³ in non-ventilated areas, with values in Rumughalu and Oyigbo exceeding the ICRP reference value of 0.29 × 10⁻³. The study concludes that proper ventilation significantly reduces indoor radon concentration, highlighting the need for regular monitoring and improved ventilation practices in residential areas within the Port Harcourt metropolis. It recommends increased public awareness and improved building practices to ensure safer indoor air quality.