This project investigates the spatial and temporal characteristics and formation mechanisms of fine particulate matter of 2.5 micrometers or less (PM2.5). The studies are conducted in the Yangtze River Delta, a typical area of particulate formation. It hopes to examine and establish the relationship between PM2.5 constituent pollution and cardio-respiratory mortality and morbidity in selected areas of China, and to provide scientific support and strategies for the formulation and revisions of laws and regulations at the national level and for key areas of the country.