The Pollution Characteristics Of Inorganic Elements,Polycyclic Aromatic Hydrocarbons And Their Derivatives,and Oxidative Potential Of PM2.5 In Shandong Province

Ambient particulate matter(PM)has significantly negative influence on human health,atmospheric pollution and even global climate change.In recent years,extreme air pollution event,such as haze,has been frequent occurrences.and PM is the primary pollutant causing haze,which has attracted the worldwide attention.Shandong Province is located in the regions that haze occurred frequently,where air pollution is serious.So far,some progress has been made in the research of polycyclic aromatic hydrocarbons(PAHs),nitrated PAHs(NPAHs),oxy,genated PAHs(OPAHs)and inorganic elements in Shandong Province.But there are still some problems,for example,the related studies mainly focused on urban regions,and the sampling duration was long.Moreover,the study of cell-free oxidative potential of PM by the method of dithiothreitol(DTT)didn’t explore the influence of bio-accessibility,and no study used ascorbic acid(AA)method to test oxidative potential until now in Shandong Province.For these crucial issues,in this work,gaseous and particulate samples were collected in typical regions in Shandong Province,analyzing the pollution characteristics and sources of PAHs,NPAHs,OPAHs and inorganic elements,then simulating human lung fluid by preparing Gamble’s solution,testing oxidative potential of PM by DTT and AA.In addition,the PM2.5 samples around 2016 Chinese New Year.s(CN’Y)holiday were obtained to explore the influence of fireworks burning on chemical components of PM2.5PM10.PM2.5 and PM 1.0samples in winter.2014 at a marine background site(Tuoji island)were collected,and PM2.5 and PM 1.0 in summer,2015 at an inland urban site(Jinan),a mountain background site(Mt.Tai)and Tuoji island were also collected.then organic carbon(OC),elemental carbon(EC)and water soluble organic carbon(WSOC)were analyzed.The results indicated that the concentrations of OC in PM10.PM2.5 and PM1.0 in Tuoji island in winter were 13±9.4 μg m-3,10±7.9 μg m-3 and 7.7±5.3 μg m-3,respectively,EC concentrations were 2.44±1.6 μg m-3,1.8±1.2 μg m-3 and 1.3±0.8 μg m-3,respectively,and WSOC concentrations were 6.1±5.0 μg m3,4.6±3.8 μg m-3 and 3.4±2.8 μg m-3,respectively.The ratios of SOC/OC in PM10,PM1.0-2.5 and PM2.5-1.0 were 62%,62%and 49%,respectively,implying that secondary formation in fine PM made a larger contrnbution than that in coarse PM.More than half(56%)of OC,EC,WSOC and SOC in PM10 mainly concentrated in PM1.0.The correlation coefficient between SOC and WSOC decreased with the increase of PM size,suggesting that WSOC in fine PM mainly derived from secondary formation,but WSOC in coarse PM mainly came from primary emissions.In summer,the concentrations of OC in Jinan in PM2.5 and PM1.0 were 12±2.4 μg m-3 and 10±2.1 μg m-3 respectively,which were obviously higher than those in Mt.Tai and Tuoji island by a factor of 1.3(PM2.5)and 1.5(PMi1.0),1.9(PM2.5)and 1.9(PM1.0),respectively.The concentrations of EC in Jinan in PM2.5 and PM1.0were 1.9±0.69 μg m-3 and 1.4±0.58 μg m-3,respectively,which were obviously higher than those in Mt.Tai and Tuoji island by a factor of 1.3(PM2.5)and 1.4(PM1.0),2.7(PM2.5)and 2.5(PM1.0),respectively.OC and EC in PM2.5 mainly existed in PM1.0 in the three sampling regions.The concentrations of EC in Jinan were relatively high during the morning and night pernods,indicating the contribution of traffic emissions to EC.The concentrations of EC in Mt.Tai and Tuoji island were the lowest in the nighttime compared with those during the other three sampling periods.The ratio of SOC/OC in summer in Tuoji island(more than 70%)was higher than that in Jinan and Mt.Tai.The back-trajectory calculation in winter indicated that the air pollution in Tuoji island was mainly influenced by air masses from the north of China,especially the southwest of Shandong Province.In summer,the air masses in Jinan mainly came from local sources of the north of Shandong Province,while in Mt.Tai and Tuoji island air masses mainly came from Yellow Sea,then passed through Shandong Province,finally arrived in the sampling regionsGaseous and particulate samples in Jinan,Mt.Tai and Tuoji island in winter,2014 under clean and haze weather conditions were collected.The results showed that combined gaseous and particulate concentrations of PAHs,NPAHs and OPAHs in Jinan were 306 ng m-3.2.8 ng m-3 and 9.1 ng m-3,respectively,which were much higher than those in Mt.Tai and Tuoji island,and the concentrations in Mt.Tai showed the lowest concentrations(38 ng m-3,0.27 ng m-3 and 1.6 ng m-3).In the three sites,Fluorene(FLU)and phenanthrene(PHE)were the most abundant components,accounting for 17%-32%and 23%-31%of the PAHs,respectively.The percentage of 3-ring PAHs to PAHs in Jinan was much lower those in Mt.Tai and Tuoji island.But the percentage of 5,6,7-ring PAHs in Jinan was much higher than those in Mt.Tai and Tuoji island.Compared with that in clean days,haze days can promote the accumulation of PAHs,especially for high molecular weight PAHs.The main emission sources of PAHs in the sampling regions were coal/biomass combustion.The air masses were the most aged in Mt.Tai under the same weather condition(clean days).The relatively strong secondary formation was found in Mt.Tai,OH-initiated radical reactions at the three sites was the main reaction pathway.High molecular weight PAHs with relatively high logKp was more easy to absorb or adsorb in PM.LogKp in Jinan was much lower than that in Tuoji island and Mt.Tai.especially in Mt.Tai.Compared with parent PAHs,NPAHs and OPAHs prefered to exist in PM.The linear fitting between logKp and supercooled saturated vapor pressure(logPL0)indicated that the gas-particle partitioning of PAHs might be in non-equilibriuimPM2.5 samples in summer.2015 in Jinan.Mt.Tai and Tuoji island at 3.5 h and 11.5 h intervals during the daytime and nighttime,respectively,were obtained.The concentrations of PAHs,NPAHs and OPAHs in Jinan(19 ngm-3,154 pg m-3 and 0.85 ng m-3)were much higher than those in Mt.Tai(5.4 ng m-3,47 pg m-3 and 0.28 ng m-3)and Tuoji island(4.4 ng m-3,43 pg m-3 and 0.22 ng m-3).The concentrations of PAHs and NPAHs in Jinan and Tuoji island were higher during the morning and night periods,but PAHs and NPAHs in Mt.Tai were higher during the morning and day periods.The peak of 1N-PYR and 7N-BaA(as the tracer of traffic emission)concentrations were found during the morning and night period,which was consistent with the rush time in urban regions,indicating the contribution of traffic emissions to PAHs and NPAHs.The results from diagnostic ratios in summer suggested that fossil fuel and biomass combustion were the main sources,and the contribution of coal burning in winter was higher than that in summer.The air masses in Tuoji island was the most aged.The OH-initiated radical secondary formation was stronger than that in winter.The cancer risk in Jinan was much higher than those in background regions.Fireworks burning can emit a large amount of air pollutants,which have importantly negative health effects.Until now,fireworks burning has not been prohibited in rural regions in China,but the air pollution from fireworks burning was serious in rural regions.So PM2.5 samples were collected around 2016 CNY’s holiday in three rural and one suburban regions in Shandong and Henan Provinces,and the inorganic water-soluble ions(WSⅡs),OC,EC,WSOC,inorganic elements,PAHs and NPAHs were analyzed.Estimated PM2.5 concentrations in the sampling regions in Shandong Province were much higher than the national air quality standard limit(Grade Ⅱ,75 μg m-3),indicating that the PM pollution in the sampling regions were serious.Fireworks burning can increase the concentrations of K+,water insoluble organic matter(WIOC),Cl,K,Cl,S,Cu and Sr.The concentrations of PAHs during the sampling period in Qingzhou(238±148 ng m3)was much higher than in rural regions in Heze(204±127 ng m-3),Liaocheng(195±54 ng m-3)and Xiping(79±29 ng m-3).The concentrations of NPAHs in Qingzhou(6.1±4.9 ng m-3),Heze(5.4±3.8 ng m-3)and Liaocheng(5.9±2.5 ng m-3)were similar,which were much higher than that in Xiping(1.9±0.91 ng m-3)Compared with that before fireworks burning period.the concentration of PAHs during fireworks burning period slightly increased by a factor of 1.0-2.0.The percentage of 4-ring PAHs to PAHs slightly increased.the percentage of 5,6-ring decreased or did not show large difference during fireworks burning period,indicating that fireworks burning was not an important sources of PAHs.The concentration of NPAHs during fireworks burning period decreased or was comparable compared with that before fireworks burning period.but 9N-ANT levels obviously increased,indicating that fireworks burning was not an important source of NPAHs,but biomass burning during fireworks burning period lmaybe increased,which can be proved by the increase of the ratio of 9N-ANT/1N-PYR.During the sampling period,coal/biomass burning was the main sources.In the sampling regions,the incremental lifetime cancer risk(ILCR)were higher than 10-6,but lower than 10-4,suggesting that exposure to PAHs and NPAHs has potential carcinogenic risk,especially for adults(30-70 years old)and toddler(1-6 years old)In this work,PM2.5 were collected in Jinan and coastal(Weihai)urban regions from April to June,2018,then the pollution characteristics of inorganic elements was studied.In this work,we extracted PM2.5 by simulated human lung fluid(Gamble’s solution),used DTT and AA to test the oxidative potential of dissolved PM2.5.During the sampling period,the concentrations of inorganic elements in Jinan and Weihai were 28±1 8 μg m-3 and 10±6.7μgm-3.respectively.and Ca,Al.K,Fe,Mg and S in Jinan,Ca,Fe,Ti and K in Weihai were the abundant elements,accounting for more than 80%of the total elements.Only As(7.0 ng m-3)in Jinan exceeded the national air quality standard limited value(5 ng m-3).In Jinan,the main sources of inorganic elements were dust or crustal source.traffic emissions and coal combustion,while the main sources in Weihai were dust or crustal source,vehicle emissions,industrial emissions and oil combustion(mainly related to shipping emissions).The potential source regions of inorganic elements in Jinan were Jiangsu,Anhui,Henan,Hebei and Shandong Provinces by concentration weight trajectory(CWT),but in Weihai,mainly in Shandong Province,Yellow Sea,and Jiangsu Province.The risk assessment of inorganic elements including Cr,As,Co,Cd,V and Pb indicated that the health risk in Weihai was lower than that in Jinan,but the carcinogenic risk of Ni in Weihai was much higher than that in Jinan.OPDTT(1.7 nmol DTT min-1 m-3)and OPAAv(1.6 nmol AA min-1 m-3)in Jinan were higher than those in Weihai(OPDTTv:0.94 nmol DTT min-1 m-3;OPAA v:1.0 nmol AA min-1 m-3).The OPDTTv in Jinan and Weihai were much lower than the results from previous publications such as Tianjin,Beijing,Yantai and Jinzhou.OPAAv,in Jinan and Weihai were related to inorganic elements from human activities.The OPDTTv in Jinan was not influenced by elements,but in Weihai S,Sn and Zn may make some contribution to OPDTTv.In this study,many monitoring methods were used,and we obtained a large amount of data on toxic components in different sampling regions in Shandong Province,and preliminarily analyzed the oxidative potential of PM.The work in this paper can offer the effective data for the further study.