[Characteristics of Reactive VOCs Species During High Haze-Pollution Events in Suburban Area of Shanghai in Winter].

Based on the online measurements of VOCs of high pollution process at the university site in winter, VOCs' characteristics and species at different levels of haze pollution were analyzed. Fifty-five VOCs were detected during sampling. ∑55VOCs concentrations ranged between 25.5×10-9-1320.3×10-9(avg±SD,240×10-9±181×10-9). Toluene and xylene were the major pollutants during high pollution process, the concentrations of which were higher than those of industrial area. The university site shared a similar VOC composition with that of industrial area, which suggested that it might be influenced by the surrounding industries. VOCs species exhibited high concentrations in nighttime while low concentrations in daytime. The ozone concentrations were on the contrary. Aromatic hydrocarbons were predominant with a high percentage of contribution (70.0%) to OFP (ozone formation potential). Alkenes and alkynes were the second highest group (16.7%). The OFP of VOCs was 2078.2×10-9 under the west-south wind direction, about 4 times higher than the value under other wind directions (505.8×10-9). Aromatic hydrocarbons exhibited a predominant contribution to OFP at different levels of haze pollution in this area, among which, Toluene and xylene contributed more than 50% to OFP. The newest version of EPA PMF model was used to identify the major source of VOCs and evaluate their contributions. Gasoline sources and vehicle exhaust, refinery and petroleum products, solvent use and organic synthetic materials were the identified VOC sources in the study area, contributing 33.1%, 31.5%, 30.5%, and 4.9%, respectively to the ∑55VOCs concentrations.