Clean Air China (CAC): Breaking Down the Dome: Sino-Swiss Cooperation on Air Pollution Source Apportionment for Better Air The project will support the development of advanced air pollution source apportionment techniques with a Swiss and Chinese joint expert team to enable the design of more effective air pollution control policies beneficial for public health, the global climate and the environment. The techniques and experience of science-based policy making will be piloted in Chinese cities and shared with other developing countries strongly affected by air pollution to accelerate progress towards cleaner air.