Changes in the Distribution of Absorbed Dose Rate in Air Due to Urbanization on Phu Quoc Island, Vietnam

In our 2024 survey on Phu Quoc Island, we found a 1.1-fold increase in the absorbed dose rate in air compared with the 2020 survey due to urbanization. However, the dose rate may have become stabilized owing to stagnation of urban development caused by the COVID-19 pandemic. We found certain types of agricultural lands and buildings also resulted in higher activity concentrations of natural radionuclides, and although the air dose rate increased from 2020, the estimated annual effective dose due to external exposure (0.22 mSv) was below the average for Vietnam. We believe that periodic measurement of absorbed dose rate in air may serve as an indicator that can indirectly assess the progress of urbanization.