Comparison of spatial interpolation methods based on exposure assessments of air pollutants: A case study on nuclear substances in Fukushima

In response to accidents and disasters involving the proliferation of pollutants to the environment, performing exposure assessments across a region of impact is important for evaluating health effects. Owing to the typical unavailability of the spatially continuous data of pollutant concentrations immediately after accidents, various spatial interpolation methods have been studied to assess exposures using limited available data. In this study, we compared representative spatial interpolation methods based on the estimation of the distributions of exposures through a case study of the Fukushima Daiichi nuclear disaster initiated by the Great East Japan earthquake and subsequent tsunamis. The nearest neighbour method, inverse distance weighted method, and ordinary kriging method were compared in the context of exposure assessments. Even though estimated air dose rates were slightly different depending on the method used, different interpolation methods produced significantly equivalent estimates of the distribution of cumulative exposure over one year.