Process analysis and sensitivity study of regional ozone formation over the Pearl River Delta, China, during the PRIDE-PRD2004 campaign using the Community Multiscale Air Quality modeling system X. Wang1, Y. Zhang1, Y. Hu2, W. Zhou1,*, K. Lu1, L. Zhong3, L. Zeng1, M. Shao1, M. Hu1, and A. G. Russell2 1State Key Joint Laboratory of Environmental Simulation and Pollution Control, College of Environmental Sciences and Engineering, Peking University, Beijing, China 2School of Civil and Environmental Engineering, Georgia Institute of Technology, Atlanta, Georgia, USA 3Guangdong Provincial Environmental Monitoring Center, Guangzhou, China *now at: Department of Civil and Environmental Engineering, Rice University, Houston, Texas, USA
Abstract. In this study, the Community Multiscale Air Quality (CMAQ) modeling system
is used to simulate the ozone (O3) episodes during the Program of
Regional Integrated Experiments of Air Quality over the Pearl River Delta,
China, in October 2004 (PRIDE-PRD2004). The simulation suggests that O3
pollution is a regional phenomenon in the Pearl River Delta (PRD). Elevated
O3 levels often occurred in the southwestern inland PRD, Pearl River
estuary (PRE), and southern coastal areas during the 1-month field campaign.
Three evolution patterns of simulated surface O3 are summarized based
on different near-ground flow conditions. More than 75% of days featured
interactions between weak synoptic forcing and local sea-land circulation.
Integrated process rate (IPR) analysis shows that photochemical production
is a dominant contributor to O3 enhancement from 09:00 to 15:00 local
standard time in the atmospheric boundary layer over most areas with
elevated O3 occurrence in the mid-afternoon. The simulated ozone
production efficiency is 2–8 O3 molecules per NOx molecule
oxidized in areas with high O3 chemical production. Precursors of
O3 originating from different source regions in the central PRD are
mixed during the course of transport to downwind rural areas during
nighttime and early morning, where they then contribute to the daytime
O3 photochemical production. The sea-land circulation plays an
important role on the regional O3 formation and distribution over PRD.
Sensitivity studies suggest that O3 formation is
volatile-organic-compound-limited in the central inland PRD, PRE, and
surrounding coastal areas with less chemical aging (NOx/NOy>0.6),
but is NOx-limited in the rural southwestern PRD with aged air
Citation: Wang, X., Zhang, Y., Hu, Y., Zhou, W., Lu, K., Zhong, L., Zeng, L., Shao, M., Hu, M., and Russell, A. G.: Process analysis and sensitivity study of regional ozone formation over the Pearl River Delta, China, during the PRIDE-PRD2004 campaign using the Community Multiscale Air Quality modeling system, Atmos. Chem. Phys., 10, 4423-4437, doi:10.5194/acp-10-4423-2010, 2010.