China's air pollution crisis: Science and policy perspectives

China's air pollution crisis, which has profound effects on the environment and human health, has attracted a great deal of scientific and media attention both domestically and internationally. Over the past few years, major policy initiatives for pollution abatement have been put in place, and air-quality monitoring data in many regions has actually begun to show marked and sustained improvement. This article serves as an introduction to the special journal issue entitled China's air pollution crisis: Science and Policy perspectives, which brings together new empirical contributions on this important topic. The article outlines past trends in the air pollution crisis and examines emerging research to discuss what the future may hold. It also provides an in-depth analysis of the various measures - including scientific and technological innovation in key sectors such as energy, top-down policy initiatives, and citizen engagement - that are integral to the emissions reductions now being achieved. Finally, the article considers the implications of these trends for the control of air pollution in China today and into the future.