Distributions And Health Risk Assessment Of Atmospheric VOCs In A Coastal City In The Northern Yangtze River Delta

To evaluate the characteristics of volatile organic compounds?VOCs?,which are important precursors of ground-level ozone formation and secondary organic aerosol?SOA?,a thirteen-month campaign for VOC measurement at different areas in Lianyungang was conducted from Apr to Sep in 2018 and Apr to Oct in 2019.57 Photochemical Assessment Monitoring Station?PAMS?and 15 carbonyl species were analyzed.Combined with meteorological parameters and trace gases,the distribution characteristics,photochemical reaction activity,source apportionment and health risk assessment of VOCs at different areas in Lianyungang were analyzed in detail.The results are showed as follows:?1?The mean concentrations of VOCs were highest in the urban area(51.05?g·m^-3),followed by the industrial(46.76?g·m^-3)and the suburban area(40.59?g·m^-3).The proportions of VOC components at different functional areas were similar,except the Kuangshan institute site,all showed alkanes?36.68-43.28%?>carbonyls?33.06-37.06%?>aromatics?15.89-21.19%?>alkenes?5.42-7.79%?>acetylene?0.59-1.30%?.Compared with the alkanes concentrations in 2018,there was a significant increase at different functional areas in 2019.The concentrations of PAMS species in Lianyungang City were notably lower than those in other cities in China.The seasonal variation of PAMS species in Lianyungang was approximately the same at different areas.While the concentrations of different components were at similar levels in the urban and industrial areas,they were all significantly higher than those in the suburban area.Acetone and 2-butanone,which were the most abundant species of carbonyls in Lianyungang,showed a higher level than in other cities and rural areas in China.The seasonal variation of carbonyls was the same in all functional areas in Lianyungang and highest in spring and lowest in autumn.Since the sampling sites in the suburban area in Lianyungang were located around the scenic spots,the weekend effect of the suburban area showed that the concentrations of VOCs on weekends was higher than that on weekdays.The PCA results showed that the sources of VOCs at different functional areas in Lianyungang were similar,including industrial emissions,plants,vehicle exhaust,fuel volatilization,combustion sources,industrial raw materials and solvent usage.?2?According to the maximum incremental reactivity?MIR?method,the most important VOC group for the ozone formation potential?OFP?at different functional areas was the aromatics?35.55-45.05%?and then the carbonyls?23.38-31.60%?.The mean OFP was highest in the urban area(134.91?g·m^-3),followed by the industrial(131.58?g·m^-3)and the suburban area(104.28?g·m^-3).The most important VOC group for SOA formation potential at different functional areas was the aromatics?88.63-92.16%?,of which the C8components contributed the most?31.44-42.15%?.The mean SOA was highest in the industrial area(63.56?g·m^-3),followed by the urban(61.86?g·m^-3)and the suburban area(43.40?g·m^-3).The OFP and SOA analysis on the top ten species suggested that the mitigation vehicle exhaust and industrial emissions should be an effective measure in controlling O₃formation in Lianyungang.Controlling aromatic species such as m,p-xylene,toluene,etc.,which were mainly from solvents usage and gasoline volatilization,can effectively control the formation of SOA.?3?The non-carcinogenic and carcinogenic risk assessment value of VOC species?aromatics and carbonyls?at different areas in Lianyungang were acceptable for local people.Between different fuctional areas,there were still some value differences.The health risk assessment value was the largest in the industrial area,followed by the urban and suburban area.Compared with 2018,the non-carcinogenic risk and carcinogenic risk of acetaldehyde increased significantly in 2019,resulting in a higher total non-carcinogenic risk and carcinogenic risk in 2019 than in 2018.The non-carcinogenic risk of acetone and 2-butanone decreased in 2019 compared with 2018,especially in industrial areas,indicating that the solvent usage source was controlled effectively in 2019.