Visibility Trends in Korea During the Past Two Decades

摘要

During the past two decades, primary pollutants in the ambient air have been substantially reduced in Korea by aggressive government efforts such as the switchover to clean fuels and equipment of automobiles with a three-way catalytic converter. However, visibility impairment in Seoul and major metropolitan areas has been a stubborn problem. It is apparent that both directly emitted fine particles mainly from vehicles and secondary fine particles from photochemical reactions could contribute to this visibility impairment. In addition, Korea is located downwind of the prevailing westerlies from China and is infiuenced by the emissions of air pollutants in China. In order to assess this complicated problem of visibility impairment, the visibility trends for the past 17 years observed at more than 60 stations throughout the country were analyzed. It was tried to largely categorize trends in major metropolitan areas compared with those in rural areas, and trends in coastal areas compared with those in inland areas. Local characteristics distinguished from neighboring areas were also discussed.