Characteristics And Source Apportionment Of VOCs Pollution In The Urban Agglomeration Of The Yangtze River Delta

Volatile Organic Compounds(VOCs)is an important precursor of urban ozone.It is of great significance to study its pollution characteristics and sources for the control of ozone pollution.In this study,the atmospheric VOCs on-line monitoring system was used to select the typical cities of Suzhou,Nanjing,Shanghai,Hangzhou and Wuhu in the Yangtze River Delta and to study the atmospheric VOCs concentration characteristics,composition changes and source analysis in combination with the conventional pollutants and meteorological data observed synchronously,providing a scientific basis for the control of ozone during the G20 conference.The results are as follows:The spring and summer observations of ozone pollution in Suzhou,a city in the hinterland of the Yangtze River Delta,show that:the average VOCs volume fraction of Suzhou Qing Jianhu in spring and summer was 28.67×10-9 and 31.26×10-9,respectively.The diurnal variation was obvious,the peak appeared in double and the peak of the peak in the morning and evening.The analysis of the characteristic species ratio method showed that the VOCs mainly came from the pollution emission of the surrounding industrial park and the PMF model.Model analysis shows that motor vehicle exhaust,industrial emission and coating/solvent use are the main sources of VOCs in this area,especially in the period of ozone pollution,VOCs mainly comes from the use of solvent/coating and industrial emissions.G20 summit period,in accordance with the unified deployment of the Ministry of environmental protection.The average concentration of VOCs in Suzhou is around 30×10-9,and Nanjing is around 20×10-9,Shanghai is around 28×10-9,Hangzhou is around 9×10-9,Wuhu is around 20×10-9.Except for Hangzhou,the concentration of VOCs in cities is obviously lower than that in other two stages.The concentrations of VOCs in Suzhou and Shanghai with similar geographical location are relatively close,while the concentrations of VOCs in Nanjing and Wuhu are relatively close.During the conference,the concentrations of VOCs in Suzhou,Nanjing and Shanghai had the same trend.Paraffins are the most important VOCs components at each observation point.The trend of aromatic hydrocarbons,alkenes and alkynes is slightly different before and after control,control and control.The trend of each component in Suzhou,Nanjing and Shanghai is the same,the components of each component are the lowest in control,and there is a clear upward trend in each component in the later stage of control,and the Hangzhou tube is in the Hangzhou tube.Before the control,the components were similar to those in the control.Wuhu aromatic hydrocarbons increased slightly in the control.The main components of each VOCs component are different,which are mainly reflected in the active components such as aromatic hydrocarbons and olefins.The ratio of characteristic species showed that the sources of VOCs in different regions were different.The OFP values of each observation point during the meeting were different,from high to the end is Shanghai>Suzhou>Nanjing>Wuhu>Hangzhou.The main OFP species among the sites are also different.The main OFP species in Shanghai are toluene,M/p-xylene and xylene.The main components are aromatic hydrocarbons.The main OFP species in Suzhou are propylene,twelve alkanes and styrene,the main components are olefins and alkanes,and the most important OFP species in Nanjing are ethylene,between two and to two.Toluene and propylene are the main components of olefins and aromatic hydrocarbons.The main OFP species in Wuhu are toluene,ethylene and xylene.The main components are aromatic and olefins,and the main OFP species in Hangzhou are ethylene,toluene and M/p-xylene,and the main components are olefins and aromatic hydrocarbons.Except for Suzhou,the main OFP contribution of each site is olefins and aromatic hydrocarbons.The OFP contribution of alkane in Suzhou site is also obvious,which may be related to the layout of industrial production around it.Analysis of the sources of VOCs in each city shows that Nanjing has a greater contribution to the pollution of VOCs,followed by industrial production and the use of solvents/coatings;Wuhu has a greater contribution to VOCs pollution than automobile exhaust,followed by industrial emission and solvent/coating use,similar to that in Hangzhou;Suzhou has contributed more to VOCs pollution than industrial emissions,followed by industrial emissions.It is the use of vehicle exhaust and solvent/coating.Shanghai's contribution to VOCs pollution is mainly solvent/paint usage,followed by vehicle exhaust and industrial emissions.In general,the proportion of VOCs sources in various places is mainly influenced by the local industrial layout and industrial structure.Suzhou and Nanjing are greatly influenced by industrial sources.Shanghai is greatly affected by the use of solvent/paint,and Hangzhou and Wuhu are greatly affected by motor vehicle exhaust.