This study analyzed the characteristics of high PM2.5 episodes that meets the concentration criteria of Emergency Reduction Measures Plan (ERMP) in Busan during the 2015-2020, and compared with those in Seoul. As a first step, the CAPSS-2017 emission data was employed to analyze the emission differences between Busan and Seoul, and pointed out that Busan emission included the dominance of ship emissions (37.7%) among total PM2.5 city emissions, whereas fugitive PM2,5 emission was the highest in Seoul. These emission characteristics are indicating that the controlling action plan should be uniquely applied to cope with ERMP in each region. We selected extremely high PM2.5 episode days that meet the criteria of ERMP levels. In Busan, Ulsan, and Gyeongnam region, 15, 16, and 8 days of extremely high PM2.5 cases were found, respectively, whereas Seoul showed approximately doubling of occurrences with 37 cases. However, the occurrences in summer season indicated big differences between two cities: the proportion of summer-season occurrence was 13-25% in Busan, whereas no single case have occurred in Seoul. This is suggesting the needs of comprehensive summer emission reduction plan with focusing on sulfur reduction to effectively cope with the ERMP levels in summer in the southeastern region, including Busan.

Abstract
1. 서 론
2. 재료 및 방법
    2.1. 사용된 자료
    2.2. 비상저감 사례 선정
    2.3. 남동권 황산화물과 2차 생성 성분 분석
3. 결 과
    3.1. 지역별 배출량 특성
    3.2. 부산지역 비상저감 해당 사례 분석
4. 고 찰
5. 결 론
REFERENCES

• 최다니엘(부산대학교 지구환경시스템학부 대기환경과학과/환경부 국가미세먼지정보센터 정책지원팀) | Daniel Choi (Department of Atmospheric Sciences, Pusan National University/Policy Support Team, National Air Emission Inventory and Research Center)
• 허국영(환경부 국가미세먼지정보센터 정책지원팀) | Gook-Young Heo (Policy Support Team, National Air Emission Inventory and Research Center)
• 김철희(부산대학교 지구환경시스템학부 대기환경과학과/환경부 국가미세먼지정보센터 정책지원팀) | Cheol-Hee Kim (Department of Atmospheric Sciences, Pusan National University/Institute of Environmental Studies, Pusan National University) Corresponding author