Radiological risk assessment for an urban area: Focusing on an air contamination event

This paper specifically discusses an atmospheric dispersion modeling and health risk assessment for Cs-137 to assess the potential and actual effects on human health from an inhalation event due to a radiological terrorist attack in the Seoul metropolitan area, Korea. The source term was assumed to be 5 TBq of Cs-137, introduced into the central part of Seoul's metropolitan area by a terrorist attack. Atmospheric dispersion models can be used to support the decision making and risk assessments when terrorist attacks have happened in an urban area. The concepts of Gaussian plume modeling and computational fluid dynamics modeling were used to calculate the Cs-137 concentration in the air. Mortality risk and morbid risk coefficients for the inhalation of contaminated air were used to assess the human health risk. The mortality and morbidity are 1.12E-2 and 1.64E-2, respectively in case of the Gaussian plume, while 6.23E-3 and 9.13E-3 in case of the computational fluid dynamics model. The results of the modeling are dependent on the terror scenarios and dispersion models. Accordingly, the optimization process is needed for final decision making.