[O₃ Source Characteristics of an Industrial Area in the Yangtze River Delta Based on Boundary Observations]

To study the characteristics of ozone sources in a petrochemical industrial park in Shanghai, O₃ and its precursors were synchronously and continuously measured for 3 months(June-August 2020) alongside meteorological parameters using an online monitoring system. The Texas Commission on Environmental Quality(TCEQ) method and principal component analysis(PCA) were used to study the contribution of regional background and local O₃ concentrations in the industrial zone, the results of which were compared. The results indicated that:① During the observation period, the dominant wind directions in the park were southeast and east, and the average temperature was 27.12℃. The daily average ρ(VOCs-36), ρ(NO), and ρ(O₃) was 32.05-240.51, 10.15-47.51, and 31.81-144.43μg·m^-3, respectively. Alkanes are the most abundant of 36 VOCs; ② The regional background concentrations based on the TCEQ method ranged from 32.63 to 191.13μg·m^-3, and the local concentrations ranged from 16.08 to 134.25 μg·m^-3. The percentage contribution of the regional background ranged from 32.6% to 87.7%. The PCA analysis showed that the regional background concentrations ranged from 66.3 to 219.83μg·m^-3; ③ The variations in local O₃ concentrations based on the TCEQ analysis broadly correspond to the variations in ozone formation potential in the park. The two analysis methods were consistent, verifying that the results are reliable; and ④ After eliminating the calculation error caused by the abnormal concentrations recorded at some stations, the proportion of background O₃ in the region was generally within the range 75%-95% during the observation period. Overall, regional transport was the main source of O₃ in the industrial park, and O₃ pollution in the surrounding cities should be the focus of pollution control alongside joint prevention and control measures in the Yangtze River Delta region.