Relative Stringency of Permitted Emission Standards Compared with Best Available Techniques–Associated Emission Levels and Changes in Emission Intensity: A Study on Waste Incineration Facilities

The Integrated Environmental Management System (IEMS) was introduced in Korea in 2017 to shift from a single-media regulatory framework to an integrated, facility-based environmental management approach. As part of this system, Best Available Techniques–Associated Emission Levels (BAT-AELs) provide reference ranges for achievable emission levels and serve as a basis for establishing sector-specific emission limits and facility-level permitted emission standards. However, in practice, permitted emission standards are finalized through emission impact assessments that consider local environmental quality. Nevertheless, it remains to be further empirically examined whether the stringency of BAT-AEL compared to permitted emission standards has been reflected in actual emission reduction outcomes. Accordingly, this study empirically evaluates the relationship between the stringency of permitted emission standards and environmental performance following the implementation of the IEMS, providing insights for future policy discussions. Municipal waste incineration facilities were selected as the study subject because relatively long-term operational data are available for this sector. Publicly available data from the CleanSYS and Integrated Environmental Permit System (IEPS) were utilized. Environmental performance was assessed using emission intensity (kg/ton-waste), defined as pollutant emissions per ton of waste incinerated. For five air pollutants (dust, sulfur oxides, nitrogen oxides, carbon monoxide, and hydrogen chloride), the stringency of permitted emission standards was quantified as a normalized value within the BAT-AEL range, and the reduction performance was evaluated based on its relationship with changes in emission intensity. Statistically significant association was not observed between stringency and changes in emission intensities across the examined pollutants. However, emission intensities for nitrogen oxides, dust, hydrogen chloride, and sulfur oxides showed significant reductions after the IEMS implementation, indicating overall emission reduction performance under the IEMS. These results suggest that although emissions improved after IEMS implementation, the magnitude of improvement was not directly associated with differences in the stringency of permitted emission standards. Thus, differences in environmental performance among facilities cannot be sufficiently explained by the numerical stringency of permitted emission standards based on BAT-AEL alone. It suggests that the actual level of BAT implementation, and the facility operating conditions should be considered together when interpreting the environmental improvement outcomes. The findings also provide practical implications into developing a management framework where BAT-AEL and monitoring data can be more effectively linked to the establishment and improvement of permitted emission standards.