The Pearl River Delta (PRD) is located in the southern coast of China and it is the second largest delta of the country. In 2014, several exceedances to the chinese limit-values, for nitrogen dioxide (NO) and ozone (O), were recorded in the PRD. To implement measures for air quality improvement in this region, it is necessary to understand the spatial distribution of air pollution. Therefore, the present work aims to study air pollution patterns, focusing on O and NO, over the PRD region by the application of the WRF-CAMx regional air quality modelling system. The WRF-CAMx system was applied, with its nesting capabilities, to one winter and one summer 7-day periods of the year 2014 and was validated with data from several air quality monitoring stations distributed along the southern coast of China. The results for the higher resolution domain showed a reasonable performance of the model. The WRF-CAMX tends to overestimate and underestimate the O and NO concentrations, respectively. The analysis of temporal and spatial variability of simulated concentrations pointed to the need to improve the emission inventory with further information on the temporal and spatial distribution of local sources.