A Study on the Comparison of Emission Factor Method and GEMS (Continuous Emission Monitoring System)

Generally, air pollutant emission at workplace is estimated by two methods: indirect methods using emission factors and direct methods based on CEMS (Continuous Emission Monitoring System). CAPSS (Clean Air Policy Support System) is a representative indirect method and the national air pollutant database of Korea. However, characteristics of some workplaces may create a gap between CAPSS and CEMS data. For improving of emission data accuracy, emission data of CEMS (named CleanSYS) equipped at 138 target workplaces were compared with those of CAPSS. As a result, SOx and PK emission levels obtained by CAPSS were lower than those of CleanSYS. SOx and PM10 emission ratios were 61.5% and 71.2% lower respectively, showing the biggest gaps. On the other hand, NOx emission of CAPSS was higher by 10.4%. SOx showed the biggest difference in 'Energy industry combustion' and NOx did in 'Production Process' within the SCC category. PK presented a large gap in 'Manufacturing industry combustion.' The differences in SOx between the two systems occurred because some large-size facilities lack pollution controllers or efficient pollution controllers. Based on this study, CAPSS emission database of Korea will improve accuracy through adopting CEMS emission system, which enables more efficient national atmospheric policies and workplace management.