Estimation and Conntermeasure of Air Pollutants Discharge from Ships in Osaka Bay

Abstract

The atmosphere over the Osaka bay area has been polluted severely for so many years that effective countermeasures against the air pollution have been requested as soon as possible. The discharge amount of NOx, SOx and CO₂ from the ships in Osaka bay are estimated in order to know how largely the marine traffic contribute to those air pollutants discharge over the Osaka bay area. The estimation results show that, (1) the ships discharge the about 40% of NOx and SOx of total amount over the Osaka bay area, though the CO₂ discharge is very small as 3%, (2) the spatial distributes intensively in the port zones and in the deep east-north region of Osaka bay mainly due to the discharge from tankers and general cargo ships staying there. The IMO/MEPC regulation, which is intending to control the air pollutants discharge of the engines installed on new ships since the year of 2000, cannot be expected so effective for the improvement of severely polluted region such as Osaka bay area. Other countermeasures such as the control of ship speed, cargo handling time, therefore, investigated here and suggests that systematic strategy could be effective when those measures are introduced together, with IMO regulation.