Until comparatively lately, the annual time series of the SO2 concentration had been shown in a decreasing trend in Ulsan as well as other Korean cities. However, the high concentration of SO2 was frequently found in the specific countermeasure region including the national industrial complex such as Mipo and Onsan in the Ulsan city for the period of 2001∼2004. There are many conditions that can influence the high concentration of SO2 at monitoring sites in Ulsan, such as: First, annual usage of the fuel including sulfur increased in comparison with the year before in spite of the fuel conversion policy which wants to use low sulfur oil less than 3% and LNG. Second, point source, such as the power plants and the petroleum and chemistry stacks, was the biggest contributor in SO2 emission, as a analyzed result of both the air quality modeling and the stack tele-monitoring system (TMS) data. And third, the air pollutants that occurred in processes of burning and manufacturing of the fuel including sulfur were transported slow into a special monitoring site by accumulating along the frontal area of see-breeze. It was concluded that Ulsan's current environmental policy together with control methods should be changed into the regulation on total amount of emission, including a market-based emission trading with calculating of atmospheric environmental critical loads, for the SO2 reduction like the specific countermeasure for the O3 and PM10 reduction in the Seoul metropolitan area. And this change should be started in the big point sources of 1∼3 species because they are big contributors of Ulsan's SO2 pollution. Especially it is necessary to revitalize of the self-regulation environmental management. Other control methods for sustaining the SO2 reduction are as follows: maintenance of the fuel conversion policy, reinforcement of the regional stationary source emission standard, and enlargement of the stack TMS.

• 문윤섭(한국교원대학교 제3대학 환경교육과) | Yun-Seob Moon Corresponding Author