| In this study,on-line rapid VOCs observation experiments were carried out in a chemical industry park and its urban environmental air station.On-line rapid monitoring of VOCs concentration in the exhaust gas of enterprises pollution sources by proton transfer reaction-timeofflightmassspectrometry（proton-transfer-reaction-time-of-flight-mass-spectrometry,PTR-TOF-MS）and long-term monitoring of VOCs in the atmosphere by on-line gas chromatography were carried out.An on-line rapid monitoring method system for VOCs in the atmosphere and exhaust gases was initially established and optimized,and applied to VOCs monitoring in organized exhaust outlets and surrounding atmospheric environment of chemical industry parks.The characteristics of VOCs emission from industrial exhaust gases and surrounding cities were further studied.VOCs Components in Urban Atmosphere and Their Effects on Atmospheric Environment.The main conclusions are as follows:A complete set of rapid on-line monitoring methods for VOCs in typical chemical industry and ambient air has been established.Based on PTR-TOF-MS monitoring data of organic chemical enterprises in the Eastern Chemical Park of Zibo City,and investigating the raw and auxiliary materials and products used by key enterprises,production processes and VOCs emissions,64 kinds of VOCs monitoring spectral libraries were formed,including 35halogen-containingorganiccompounds,10aromatichydrocarbons,14oxygen/sulfur-containing organic compounds,3 alkanes and 2 alkenes.Species.Based on Thermo 5900-C on-line gas chromatography-mass spectrometry,60 VOCs in urban atmospheric environment around the chemical park were monitored,including 29 alkanes,9alkenes,1 alkyne,16 aromatic hydrocarbons and 5 sulfur-compounds VOCs.（2）A new method for rapid and continuous monitoring of VOCs by PTR-TOF-MS is established and optimized.This method can be applied to field monitoring more simply,and real-time data can be detected online.The measuring speed is up to second magnitude,without complicated sample pretreatment,and the monitoring efficiency and accuracy are improved.The monitoring range of VOCs monomer concentration is 10 pptv-50 ppm.Distributed sampling system is used for remote sampling of gas transmission pipelines.Single PTR-TOF-MS can sample and analyze gas from multiple organized outlets.（3）VOCs emissions from three major pharmaceutical and chemical enterprises were observed by online PTR-TOF-MS（December 14,2017 to July 14,2018）for a long time.The VOCs emissions from Disman,Xinhua Pharmaceutical and Jinma Chemical Industries were studied.The variation range of total VOCs at Desman sampling sites was between 0.15 ppm and 20.37 ppm.VOCs are mainly composed of oxygen-containing organic compounds（OVOCs）and halogen-containing organic compounds.Acetone and tetrachloroethylene are the main pollutants.During the observation period,the total VOCs emissions remained basically unchanged during the daytime,but there was a phenomenon of concentrated emissions at night.（4）During the observation period from June 15 to June 27,2018,VOCs emission from Xinhua Pharmaceutical Company was much higher than that from Sinochem Disman Pharmaceutical Company.The average concentration of VOCs ranked as halogen-containing organic compounds（10.12 ppm）>aromatic hydrocarbons（5.07 ppm）>OVOCs（4.99 ppm）>alkanes（0.95 ppm）>olefins（0.31 ppm）.On the 25th and 26th days,there were pollution incidents of concentrated pollutant discharge,the most obvious increase was OVOCs and halogen-containing organic compounds.（5）During the observation period from 12 to 14 July 2018,the VOCs concentration of Jinma Chemical Company was much higher than that of Xinhua Pharmaceutical Company and Sinochem Disman Pharmaceutical Company.VOCs are mainly halogen-containing organic compounds.The first ten pollutants are chloromethane 6923.52 ppm,chloroethane 169.78ppm,1,3-butadiene 160.71 ppm,tetrachloroethylene 16.61 ppm,2-propanol 16.01 ppm,propylene 11.09 ppm,toluene 9.31 ppm,carbon disulfide 8.1 ppm,1,4-dioxane 6.01 ppm and ethyl acetate 6.01 ppm,respectively.（6）Comparing the VOCs emissions from three major chemical enterprises,we found that the three major chemical enterprises mainly emit VOCs containing halogen organic pollutants,and the proportion of species components in the two pharmaceutical industries is basically the same.The difference is that besides Jinma chemical industry,the main VOCs pollutants of Disman Pharmaceutical and Xinhua Pharmaceutical also include OVOCs.Besides halogen-containing organic substances,alkenes are the main pollutants of Jinma chemical industry.Enterprises have their own effective measures to control the pollutants in raw materials and accessories,but they fail to consider the new pollutants that may be produced in the process,such as halogenated alkanes,halogenated olefins,and oxygen-containing organic compounds.By comparing the off-line manual sampling data with the on-line data,it is found that the main VOCs pollutants can be detected,and the consistency of the concentration order is relatively good.The main pollutants in enterprises are more accurately identified and quantified,which further proves the feasibility of the method.（7）Thermo 5900-C on-line gas chromatography was used to monitor VOCs in the atmosphere around the chemical park,including Fangzhen and Dongsun.The results showed that the VOCs in Fangzhen were more polluted than those in other areas at home and abroad.The total VOCs were 87.14 ppb.The order of VOCs concentration was alkanes（39.88 ppb）>olefins（29.80 ppb）>oxygen/sulfur organic compounds（10.40 ppb）>aromatic hydrocarbons（7.99 ppb）>alkynes（6.04 ppb）.The total VOCs at Dongsun site are 41.85 ppb,with the highest proportion of alkanes（42.53%）,followed by alkenes（30.12%）,oxygen-containing organic compounds（11.85%）,aromatic hydrocarbons（8.86%）and alkynes（6.64%）.By calculating the ozone generation potential（OFP）and OH reactivity of each species,it was found that the activities of alkenes and aromatic hydrocarbons were the highest,and the maximum ozone production at Fangzhen and Dongsun sites was 1119.09 ug/m3 and 385.01ug/m3.By calculating the contribution of SOA generation,it was found that aromatic hydrocarbons were the dominant species,and the maximum production of SOA was 3.673ug/m3and1.025ug/m3,respectively.Thespeciesarem/p-xylene,toluene,1,3,5-trimethylbenzene and o-xylene.The effects of VOCs on ozone formation had been analyzed in two period which showed thatρ（O3）was closely related toρ（VOCs）and VOCs reaction activity.Whenρ（alkenes）andρ（aromatics）are not high,ozone is still at a high level due to the increase ofρ（sulphur-containing VOCs）,and sulphur-containing VOCs became the main contributors of ozone in the atmosphere.According to the discriminant method of sensitivity of VOCs/NOx ratio,it was found that ozone formation was sensitive to VOCs during the observation period,and belonged to VOCs control area. |
