Rapid industrial development has turned China into the engine of the economic growth in the world. Accompanied with the increasing manufacturing production, substantial amount of SO2, NOx, particulate matter and VOC are emitted into the atmosphere and causes the air pollution issue in this country. Facing this top environmental concern, it is important for the policy makers to understand: 1) where are the ambient pollutants coming from? 2) to what degree do the ambient pollutants influence human’s health? 3) what are the reaction mechanisms behind the pollutants in the atmosphere.

3-D Air quality model together with its source apportionment module is used to study the source apportionment of sulfate/nitrate in the rainwater, particulate sulfate/nitrate in the air and ambient NOx, respectively. The mortality caused by both short-term and long-term exposure to the ambient pollutants in the PRD region were also studied in this research. In the last chapter, a 0-D box model was used to study the HOx budget, HONO and O3 production rate at an urban site in Wuhan City. Daytime HONO budget was further analyzed by using a 1-D analytic framework. NO2 uptake coefficient was calculated and implemented into the 3-D air quality model for spatial impact investigation.