| An analysis was made by using historical observational data of Guangzhou Panyu Atmospheric Composition Station(GPACS). The results showed that typical haze processes accompanied with high ozone episodes happened during the period from September 2rd, 2011 to September 5th, 2011(P1) and the period from June 12th, 2012 to June 15th, 2012(P2) respectively. During the two combined pollution processes (P1 and P2), daily visibility ranged from 5.78 km to 6.91 km and from 5.60 km to 9.25 km, and the maximum 8 h O3reached 92.14×10-9 and 91.29×10-9 respectively. Among the 55 detected volatile organic compounds(VOCs), alkenes and aromatics had the highest reactivity with the 41%, 39% proportions of equivalent propylene concentration and the proportions of 28%, 54% in the aspect of ozone formation potential during P1. Alkenes and aromatics contributed 35% and 46% of equivalent propylene concentration, as well as 22% and 61% to ozone formation potential during P2. In terms of SOA formation potential by FAC estimation, alkanes, alkenes and aromatics accounted for 13.2%, 21.4%, 65.4% during P1 and 4.6%, 13.8%, 81.6% during P2 respectively. Toluene, isoprene, ethylbenzene and m,p-Xylene had large contributions to the ozone and SOA formation. Factors including pollutants transported from the downtown area, continuous gentle wind, high temperature, low humidity and strong radiation gave rise to the occurrence of high ozone episodes in these two haze processes. |
