Characteristics,source Analysis And Health Risk Assessment Of Indoor/Outdoor Atmospheric Polycyclic Aromatic Hydrocarbons(PAHs) And Organophosphorus Flame Retardants(OPFRs) In Petrochemical Industrial Area

Polycyclic aromatic hydrocarbons(PAHs)and organophosphorus flame retardants(OPFRs)are persistent organic pollutants that are widely present in variety environmental media and have teratogenic,carcinogenic and mutagenic properties to organisms.Industrial activities are important outdoor sources of PAHs and OPFRs.There are also multiple emission sources in indoor environment,and people spend nearly 90%of their time indoors.Therefore,it is of great significance for persistent organic pollutants’ prevention and control to understand the pollution characteristics,sources and health risks of PAHs and OPFRs in industrial zone and their impacts on surrounding residents’ living areas.Shandong Province is an important industrial base.In this study,two sampling sites were set up in Linzi District,Zibo City,a typical petrochemical base in Shandong Province.Atmospheric PM2.5 and gas phase samples were collected indoors and outdoors simultaneously from July 19 to August 1,2021(summer)and January 7 to 17,2022(winter).The concentration of 16 PAHs and 15 OPFRs were determined by gas chromatography/mass spectrometry(GC/MS),and the species composition,gas-particle distribution,potential sources.and health risks of PAHs and OPFRs near petrochemical industrial zones were studied.The concentration of ∑PAHs in PM2.5 was higher in industrial zone than living area in summer,and higher in living area than industrial zone in winter.Both in winter and summer,the concentration of ∑PAHs in outdoors gas phase was higher in living area than industrial zone,and the concentration of ∑PAHs in indoors gas phase of two sampling points was similar.In industrial zone and living area,the concentration of ∑PAHs in both particle and gas phase showed obvious seasonal differences:Outdoor winter was higher than summer,and indoor summer was higher than winter.In summer,the majority of PAHs in PM2.5 were HMW-PAHs(75.04%)outdoors,LMW-PAHs(41.58%)and MMW-PAHs(52.55%)indoors.There was no significant difference in species composition of PAHs in indoors and outdoors PM2.5 in winter:LMW-PAHs(23.93%),MMW-PAHs(32.52%)and HMW-PAHs(43.55%)all accounted for a certain proportion.In both summer and winter,the main PAHs in indoors and outdoors gas phase were LMW-PAHs(60.90%).In outdoors PM2.5,PAHs were positively correlated with PM2.5,PM10,SO2,NOx,CO and atmospheric pressure(p<0.01),but negatively correlated with O3 and temperature(p<0.01).In both phases,the temperature change had a great influence on the concentration of PAHs in indoors.The calculation of gas-particle distribution coefficient showed that compared with summer and outdoor,PAHs were more easily distributed into particle phase and closer to the equilibrium state of two phases in winter and indoor.respectively.The prediction accuracy of the gas-particle distribution model for the proportion of PAHs in particle phase was better in outdoor than indoor and better in winter than summer.The concentration of ∑OPFRs in outdoor PM2.5 was similar between industrial zone and living area.while that in indoor living area was higher than that in industrial zone.The concentration of ∑OPFRs in outdoor and indoor gas phase showed no significant difference between the two sampling points.In industrial zone and living area,the concentration of∑OPFRs in both particle and gas phase was higher in summer than winter and higher in indoor than outdoor.In PM2.5,OPFRs were mainly Alkyl-OPFRs outdoors(59.49%)and Cl-OPFRs indoors(74.36%)in summer.OPFRs were mainly Alkyl-OPFRs(46.99%)and Cl-OPFRs(37.04%)in indoors and outdoors PM2.5 in winter.In both winter and summer,the majority of OPFRs in indoors and outdoors gas phase were Alkyl-OPFRs(74.70%).The results of correlation analysis indicated that temperature was an important factor affecting the volatilizes release and gas-particle distribution of OPFRs in indoors.In summer,OPFRs were more inclined to allocate into particle phase than in winter.OPFRs were more likely to exist in particle phase than PAHs and were more difficult to reach the gas-particle equilibrium state.The gas-particle distribution of OPFRs was dominated by the absorption mechanism.The prediction accuracy of the gas-particle distribution model for the proportion of OPFRs in particle phase was related to logKOA.The results of positive matrix factorization(PMF)model indicated that PAHs in PM2.5 were mainly from coal combustion(31.63%),vehicle emission(29.01%),petroleum volatilization and industrial mixed sources(21.59%)and biomass burning and indoor cooking sources(17.77%).PAHs in gas phase were mainly from domestic and industrial mixed sources(46.48%),petroleum volatilization(34.80%)and mixed combustion sources(18.72%).The results of principal component analysis(PCA)showed that OPFRs in PM2.5 mainly came from domestic and industrial emission sources(59.13%)and oil and traffic emission sources(30.27%).Furthermore,oil and industrial emission sources(45.00%)and specific emission sources(23.64%)were the main sources of OPFRs in gas phase.The results of incremental lifetime cancer risk(ILCR)calculations indicated that the cancer risk levels of residents exposed to atmospheric PAHs through respiratory in industrial and living areas was similar,but outdoors were higher than indoors.The risk of exposure to PAHs through respiration was greater in adults than children,and the concentration of outdoor PAHs had a potential cancer risk for adults.Non-carcinogenic risk hazards quotient(HQ)and carcinogenic risk index(RI)showed that respiratory exposure to OPFRs did not cause potential non-carcinogenic risk and carcinogenic risk for industrial and living area residents.Both of the the non-carcinogenic risk and carcinogenic risk of indoors respiratory intake of OPFRs were higher than those of outdoors.and the highest risk was found in indoor living area.The noncarcinogenic risk of OPFRs was higher in children than adults,and the carcinogenic risk of OPFRs was higher in adults than children.Therefore,more attention should be paid to indoors OPFRs pollution,and paid more attention to the non-carcinogenic risk of respiratory intake of OPFRs of children,also the carcinogenic risk of adults.