Environmental quality-oriented air pollution emission permit allocation methods: A plant-level study

When implementing the emission permit system to control air pollution, current research mainly adopts top-down approaches to allocate emission quotas, lacking practicability at the plant level. In this study, two new plant-level permit allocation methods are proposed in consideration of the interference of environmental factors to help allocate emission quotas more effectively. These methods adjust the commonly-used emission standard permit allocation method by introducing the transmission of air pollutants between sources and receptor cities or by introducing the constraint of the environmental capacity. The study is conducted based on plant-level production data from 11,398 major emission units in the seven core cities of the Beijing-Tianjin-Hebei region, China. In 2017, these units emitted 139.7 thousand tons of primary PM2.5, 223.2 thousand tons of SO2, and 281.5 thousand tons of NOX, accounting for 24.8%–58.6% of the regional total emissions. The new methods could reduce emissions by up to 82.4% and reduce pollution concentrations by 12.3% maximumly. The slopes of the linear regressions between the issued and the allocated plant-level permit quotas are between 0.60 and 0.97, indicating the new methods perform well in reducing emissions at the plant level. However, as emission reduction is the ultimate outcome of multiple factors, these methods sometimes still cannot control pollution concentrations below the air quality standards due to the relatively loose environmental policy. Thus, it is recommended to tighten the emission standards to further reduce allocated permits. Overall, this work provides significant insight into improving emission allocation policies using plant-level data in real-world environmental governance in China.