Modeling of atmospheric dispersion of mercury from coal–fired power plants in Japan

The Air Quality Management Division of Ministry of the Environment in Japan selected the maximum level of annual mean air quality standard for mercury as 0.04 μg/m3. The yearly average atmospheric emissions of mercury from two nearly located point sources, background concentrations of mercury in the atmosphere and one–year meteorological data was used to predict the ambient concentrations of mercury at ground level by atmospheric dispersion modeling. To estimate the mercury concentration in the air of the local area, two different models have been used. The first one is AIST–ADMER model that estimates regional atmospheric distribution of mercury concentration. The second one is METI–LIS model that estimates the atmospheric distribution of mercury concentration in the vicinity of industrial facilities. The annual mean concentration of mercury in the atmosphere was calculated for the central Honshu Island of Japan using the AIST–ADMER model, which served as a background data for the METI–LIS model to calculate atmospheric mercury concentration in the vicinity of industrial facilities. Maximum annual mean atmospheric concentrations of mercury in the vicinity of the two hypothetical coal–fired power plants were calculated as 0.0118 μg/m3 that was lower than the Japanese annual mean air quality standard for mercury.