Abstract:The Community Multiscale Air Quality Modeling System(CMAQ), a 3-D regional chemical transport model, has been used to simulate a heavy ozone pollution episode in Shenzhen in August, 2008. 3D decoupled direct method (DDM-3D) was applied to investigate the sensitivity of ozone formation to precursor emissions from Shenzhen and other cities in the Pearl River Delta during the episode. The results suggested that anthropogenic volatile organic compounds (VOCs) had high sensitivity to ozone formation, and the key point to control ozone pollution in Shenzhen was to control the anthropogenic VOCs emissions, such as chemical industries, printing, electronics manufacturing, furniture making, toys making, shoe making, use of architectural coatings, and household solvent. The results also showed that the ozone pollution in Shenzhen was regional in extent, and to achieve the controlling objective of 8-hour average ozone concentration lower than 120 μg/m3during the adverse weather, jointly control measures should be put into practice in Shenzhen and in other surrounding cities.