• Air masses from Zhejiang Province is the major source of O3 in suburban Shanghai. • O3 formation was in VOC-sensitive regime in rural Shanghai. • O3 formation was most sensitive to propylene in rural Shanghai.
A high level of ozone (O
3) is frequently observed in the suburbs of Shanghai, the reason for this high level remains unclear. To obtain a detailed insight on the high level of O
3 during summer in Shanghai, O
3 and its precursors were measured at a suburban site in Shanghai from July 1, 2016 to July 31, 2016. Using the Hybrid Single-Particle Lagrangian Integrated Trajectory (HYSPLIT) model and concentration weighted trajectories (CWT), we found that Zhejiang province was the main potential source of O
3 in suburban Shanghai. When the sampling site was controlled by south-western winds exceeding 2 m/s, the O
3-rich air masses from upwind regions (such as Zhejiang province) could be transported to the suburban Shanghai. The propylene-equivalent concentration (PEC) and ozone formation potential (OFP) were further calculated for each VOC species, and the results suggested that propylene, (m+p)-xylene, and toluene played dominant roles in O
3 formation. The Ozone Isopleth Plotting Research (OZIPR) model was used to reveal the impact of O
3 precursors on O
3 formation, and 4 base-cases were selected to adjust the model simulation. An average disparity of 18.20% was achieved between the simulated and observed O
3 concentrations. The O
3 isopleth diagram illustrated that O
3 formation in July 2016 was in VOC-sensitive regime, although the VOC/NO
x ratio was greater than 20. By introducing sensitivity (S), a sensitivity analysis was performed for O
3 formation. We found that O
3 formation was sensitive to propylene, (m+p)-xylene, o-xylene and toluene. The results provide theoretical support for O
3 pollution treatment in Shanghai.
相似文献
