Factor decomposition and decoupling analysis of air pollutant emissions in China's iron and steel industry

With its major influences on economic growth, energy consumption, and environmental quality, the iron and steel (IS) industry plays an important role in achieving green growth of the national economy. It is also the main air pollutant emitter compared with other industries. Therefore, this study first investigates the influencing factors of air pollutant emissions of the IS industry from dimensions of environmental regulation effect, pollutant generation intensity effect, energy structure effect, technological progress effect, and scale effect using the logarithmic mean Divisia index (LMDI) method. Additionally, decoupling effort values are further calculated to obtain the efforts made in different historical stages to achieve decoupling between the growth of the IS industry and its pollutant emissions. Three main conclusions can be summarized based on the empirical analysis of China's IS industry from 2005 to 2015. First, environmental regulation plays a decisive role in mitigating air pollution in the IS industry. Second, environmental regulation and technological progress both exert inhibitory effects on air pollutant emissions, whereas the intensity effect of pollutant generation and scale effect promote emissions to some extent. The role of energy structural effect is unstable, yet the cumulative effect analysis shows that the effect exerts greater impacts on emission reduction during the recent period. Third, decoupling efforts of the industry gradually changed from weak to strong. In specific, the effects of environmental regulation and technological progress both promote decoupling. Conclusions are made, and suggestions are highlighted based on the research findings.