Since the Fukushima Dai-ichi Nuclear Power Plant accident in 2011, background radiation dose monitoring was increased throughout Japan for public assurance. In Shimokita Peninsula of Aomori Prefecture, several nuclear-related facilities are present. Background radiation monitoring data within nuclear facilities or selected residential areas in larger cities, measured by nuclear facilities or government agencies, is publicly available. To increase public involvement in radiation monitoring and encourage communication during non-emergency periods, a regional radiation monitoring project in places involved in radiation emergency response was launched in 2015. Background dose rate monitoring using personal dosimeter PM1904A POLISMART® II of four healthcare facilities and one municipal city office in Mutsu City and Higashidori Village determined the baseline level of outdoor background radiation from 2015 to 2018, which was an average of 0.0499 ± 0.011 µSv/h. Temperature, humidity, wind speed, accumulated snow and precipitation did not significantly affect dose rates measured with POLISMART. Although background dose rates measured by POLISMART were higher than those measured by monitoring posts and other detectors in similar locations and measurement periods, annual background radiation calculated from POLISMART measurements was lower than Japanʼs estimated average of 0.7 mSv/yr. From these results, POLISMART may be additionally used for environmental radiation monitoring and public education.
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