[Spatial Distribution Characteristics of NMHCs in Spring in Cangzhou City]

Simultaneous collections of non-methane hydrocarbons (NMHCs) were carried out at 15 sampling sites including urban, suburb and potential pollution areas in Cangzhou City in spring 2015. The results showed that NMHCs were generally higher in urban areas than those in suburb and rural areas; the highest concentration of NMHCs was observed at Cangzhou High-tech zone (urban area); the concentrations of NMHCs were significantly lower at rural sites than in most urban sites except Hejian site; vehicular emissions were the main sources of NMHCs in Cangzhou; Cangzhou chemical fertilizer plant and Cangzhou oil refinery had no significant influence on urban NMHCs during their shutdown period; Dagang Oilfield, with better oil and gas recovery systems, did not have a significant impact on urban NMHCs. In general, alkanes, alkenes and aromatics accounted for 65%, 16% and 19% of NMHCs in Cangzhou City, respectively; xylene (19%), ethylene (14%), toluene(11%), propylene (5%), isopentane (5%) and isopentene (5%) were the most dominant contributors to ozone formation potential; aerosol formation potential was mainly derived from toluene (28%), pinene (28%), xylene(16%), ethylbenzene (9%) and benzene (9%).