Fig.7. Calculated Results of Turbulent Diffusion of Pollutants Around Tokyo Bay Area
Fig.8. Monitoring Stations around Tokyo Bay
Fig.9. Contribution of Ships at Monitoring Stations
It is considered that the SOx concentration levels on land have been drastically decreasing in recent years by the regulation. On the other hand, for ships there has been nothing. Also it is shown that the good coastal residential area near Yokohama or Kawasaki is under the contribution percentage of NOx from ships as 10 to 20% in yearly average. In conclusion, the estimated concentration values from ships correspond to 4〜24% of environmental regulation limit in Japan for SOx, and 5〜17% for NOx. In these calculations, the sulphur content in the fuel oil is assumed as 3%. If the sulphur content is reduced to 1.5% as the new Annex VI proposed for the designated SOx Emission Control Area, the situation should be much improved.
