Characteristics and source apportionment of VOCs during heavy pollution in Xi'an in winter
The characteristics,aging degree and diurnal variation of VOCs in two pollution processes(pollution pro-cess I:from December 30,2018 to January 7,2019;Pollution Process II:from January 8,2019 to January 15,2019)were ana-lyzed,based on the continuous on-line observation data of heavy pollution period at the Xi'an Super Station(December 30,2018-january 15,2019).The sources of VOCs during heavy pollution episode were analyzed by orthogonal matrix factoriza-tion(PMF).The formation potential of secondary organic aerosols(SOA)was estimated by the method of aerosol formation coefficient(FAC).Result showed that the concentration of VOCs were(102.87±31.62)×10-9,and(103.5±45.46)×10-9 in heavy pollution process I and II.The proportion of organic compounds and alkanes was more than 60%.compared with the clean days,alkynes increased the most,oxygen-containing organic compounds and alkanes increased the most,the ratio of alkyl to acetylene was about 1.0,the air mass were old badly because of the adverse influence of diffusion conditions,The diurnal variation was high at night and low at day,with a small peak at about 08:00.The source apportionment results of PMF model showed that VOCs mainly came from industrial sources(13.05%),vehicle exhaust(27.49%),solvent sources(15.64%),fossil fuel sources(21.38%)and food sources(22.43%).By estimating the SOA generation potential,it was con-cluded that the benzene series compounds(BTEX)in aromatic hydrocarbons were the main substances of SOA pollution.
Heavy pollution episodeVolatile organic compounds(VOCs)Source resolutionSecondary organic aerosol(SOA)
万方数据
维普
