The Pearl River Delta Region (PRD) in Southern China is a rapidly developing industrial region and also faced with increasing air pollution problems. Ozone, as an important pollutant, has been extensively investigated by means of measurement or numerical model studies in PRD. However, from the macro perspective of enacting control policies in the whole PRD, we need to know how the precursors of ozone, such as NOx or VOC distribute, interact and contribute to ozone formation. To answer these questions, a systematic study of NOx source apportionment in PRD is presented in this thesis based on a 3 dimensional air quality modeling system WRF-SMOKE-CAMx and the application of OSAT probing tool. The modeling system and the model result are carefully evaluated based on 4 months’ simul...[ Read more ]

The Pearl River Delta Region (PRD) in Southern China is a rapidly developing industrial region and also faced with increasing air pollution problems. Ozone, as an important pollutant, has been extensively investigated by means of measurement or numerical model studies in PRD. However, from the macro perspective of enacting control policies in the whole PRD, we need to know how the precursors of ozone, such as NOx or VOC distribute, interact and contribute to ozone formation. To answer these questions, a systematic study of NOx source apportionment in PRD is presented in this thesis based on a 3 dimensional air quality modeling system WRF-SMOKE-CAMx and the application of OSAT probing tool. The modeling system and the model result are carefully evaluated based on 4 months’ simulation results, respectively in Jan, Apr, July and Oct. From the perspective of emission groups, detailed composition of NOx in each sub-region in PRD is revealed. The model results indicate that the emission types in each megacities in PRD have various characteristics according to the different local emission structures. In each sub region, the NOx interactions are revealed. NOx is separated to local, regional and super-regional parts in order to investigate the contribution of each component. Although the lifetime of NOx is relatively short and supposed to behave more locally, the analysis of NOx source apportionment in terms of sub-regions confirms that there are interactions of NOx among cities in PRD, especially in Jan and Oct when the meteorological conditions are more favorable for transporting NOx far away. In megacities such as GZ, SZ and HK, the local NOx is the dominant contribution, and meanwhile GZ, SZ, DG and HK have significant regional impacts of NOx to other regions.