Characteristics,Sources And Health Risk Assessment Of Atmospheric VOCs In A Chemical Industrial Park Of Zibo

As an important anthropogenic source of volatile organic compounds(VOCs),industrial sources have brought great harm to urban environment and human health.There are many enterprises in the industrial park,the pollutant discharge is complex and the discharge areas are concentrated,and there are still many problems and challenges(such as difficulty in accurately identifying pollution sources,and difficulty in perfecting the supervision system,etc.).This research area is located in Zibo Chemical Industrial Park The VOCs in the park were continuously monitored by gas chromatography-mass spectrometry/hydrogen flame ionization detector(GC-MS/FID),and the pollution characteristics and environmental impacts of VOCs in different seasons were analyzed.At the same time,the monitoring data of non-methane total hydrocarbons(NMHC)at the boundary of key enterprises in the park was used to analyze the spatial distribution characteristics of pollutants in the park.The optimal control species and pollutant sources were identified by entropy method,characteristic species ratio method and orthogonal positive factorization(PMF)model.Finally,the non-carcinogenic and carcinogenic risk of human health were quantified by a health risk assessment method(U.S.EPA).The results indicate that:(1)During the monitoring period,the overall concentration level and environmental pollution of the VOCs component monitoring station(X2)on the north side of the park were higher than the VOCs component monitoring station(X1)on the south side.Compared with each season,the two stations showed the highest TVOC concentration in autumn(X1: 65.60 ppbv;X2: 315.93 ppbv)and the lowest in winter(X1: 40.32 ppbv;X2: 96.70 ppbv),ethane,isopentane,ethylene and 1,3-butadiene were the main contributing species.Under the influence of traffic and industrial emissions,the two stations showed a "single peak" or "double peak" diurnal variation pattern.Ozone formation potential(OFP)calculations showed that olefins were the main OFP contributing components,and the main contributing species were1,3-butadiene,ethylene and propylene.Benzene,toluene and m/p-xylene were the main contributors to secondary organic aerosols(SOA)by the formation aerosol coefficient(FAC).The spatial distribution results of NMHC showed that the pollution level in summer and autumn was higher than that in winter and spring,and the pollution degree in the surrounding areas of enterprise A,B and F was higher.(2)The entropy-value analysis showed that toluene was the main first level controlled species in the chemical industry park,and the control second and third species were mainly n-pentane,isopentane and ethylene.The analysis results were combined with the list of preferred controlled species at home and abroad,and finally36 preferred controlled species were determined.The analysis of the ratio of m/p-xylene to ethylbenzene showed that the chemical industrial park had a certain degree of atmospheric aging phenomenon.According to the ratio of benzene to toluene and isopentane to n-pentane,VOCs in chemical park are mainly affected by various types of industrial emissions,and the impact of motor vehicle emissions could not be ignored.According to PMF source analysis,the main contribution sources of the chemical industrial park in each season were petrochemical and fine chemical industrial production emissions,and the average contribution proportion of industrial source emissions in each season was more than 55 %.(3)The results of health risk assessment showed that the accumulated non-carcinogenic risk and carcinogenic risk in all seasons of the chemical industrial park during the monitoring period exceeded the safety threshold recommended by EPA.The main non-carcinogenic risk specie was acrolein,followed by 1,3-butadiene and 1,2-trichloroethane.The main contributing specie was 1,3-butadiene,followed by benzene,chloroform and 1,2-dichloroethane.Combined with PMF source analysis results,industrial sources were the main health risk sources,and the contribution of health risk in each season accounted for more than 70%.