Air quality has become an important sustainability concern for China's highly developed economic regions. Taking Jiangsu Province as a case, this study investigates the effect of energy consumption on air quality when both considering and not considering control variables, such as industrial structure, energy consumption structure and energy efficiency from 2006 to 2015 and further explores the influence of the related policies on air quality and the relationship between energy consumption and air quality. One important finding is that the relationship between energy consumption and the air quality index of Jiangsu Province shows a U-shaped curve and it is now in the increasing part of the curve, which reveals the effectiveness of controlling energy consumption in improving air quality. Another important finding is that, when considering the effect of related polices, there is still a U-shaped curve relationship between energy consumption and air quality index, with the opening of curve becoming bigger and the influence of energy consumption on air quality becoming more obvious. Moreover, although air quality is improved whether considering policies separately or together, the effect of combined policies is better than is the effect of a separate policy. This not only reflects the effectiveness of related polices but also shows the importance of policy coordination. Furthermore, a 1% optimization of industrial structure inhibits air quality index by 0.0054%, while the relationship of energy efficiency and energy consumption structure with air quality is inconsistent with theoretical analysis. This implies that, in practice, there is still room for improvement in both energy saving and emission reduction and even in air quality improvement. This study may help the stakeholders, whether from Jiangsu Province, other provinces in China or other countries at the global level, identify the impacts of energy consumption on air quality and formulate effective energy saving and air quality improvement policies in conjunction with their economic characteristics.
