| Shanghai is one of the largest,most rapidly developing cities in China.This fast-paced economic growth has not been without consequence,one of them being a serious increase in atmospheric pollution.Atmospheric particulate matter,especially PM2.5,not only damages the atmosphere,but also affects people's productivity,living standards and health.Therefore,research on atmospheric particulate pollution has substantially increased.Studying the concentration,distribution and composition of atmospheric particulate matter is of great value in understanding regional and urban atmospheric pollution as well as controlling particulate pollution.In order analyze the concentrations and sources of elements of atmospheric particles in Shanghai,this study collected atmospheric particulate samples during December 2015 and May 2016.The sampling point was located at the roof of the Institute of Tourism,Shanghai Normal University.62 samples of PM2.5.5 and 6 groups?9 per group?of size-segregated aerosol were collected.All the samples were filter membrane samples.Nineteen elements?Al,As,Ba,Br,Cd,Cr,Cu,Fe,I,Mn,Ni,P,Pb,Sb,Se,Si,Ti,V,Zn?were measured by inductively coupled plasma-mass spectrometry?ICP-MS?.The following conclusions were obtained after an analysis of the concentration of elements,seasonal changes,proportions of elements and their composition:?1?The average concentration of elements showed as:Zn>Si>Fe>Br>P>Mn>Al>Pb>I>Cu>Ba>V>As>Se>Ni>Sb>Cd>Cr>Ti.The range of concentrations was0.45-189.60ng/m3,with the average of 29.84±24.12ng/m3.Elements Si,Fe,Al and P,which were mainly from the crust,showed higher concentration.Compared with other cities at home and abroad,the concentrations of As,Ba,Cd,Cr,Cu,Mn,Ni,Pb and Sb,which mainly from artificial source were significantly higher than those in foreign cities,but lower than domestic cities.The annual concentrations of elements in Shanghai showed that elements Zn,Si,Fe with higher concentrations,the concentrations of elements in PM2.5.5 had obviously seasonal variation:the concentration of elements in winter was the highest,followed by spring,summer and autumn.?2?The particle size of most elements in the size-segregated aerosol were mainly concentrated at the 5th level?1.1-2.1?m?.The heavy metal elements?Cd,Cu,Pb,Ni,V,Cr?showed similar particle size distribution which grain diameter were distributed in the range of 0.7-2.1?m.The annual concentrations of elements in size-segregated aerosol particles showed that the highest total concentration of elements in winter?1325.78ng/m3?and the lowest concentration of elements in autumn?536.51ng/m3?.The total concentrations of elements showed that the fine particles?0-2.1?m?higher than that of coarse particles?2.1-9.0?m?.Concentrations of elements in PM1.0.0 ranged from 0.20 to 171.57ng/m3.The element ratios in PM1.0.0 and PM2.5.5 ranged from 0.13 to1.58 with average of 0.62.It's said that the elements in the atmospheric particles occupy greater proportion in PM1.0.0 during sampling period.The ratios of metallic elements Cd,Al,Pb,Ba,Cu,Mn,Ni,V were lower than 0.5,it is indicated that most of the metal elements in atmospheric particulates are mainly attached to PM2.5.?3?Comparing the concentrations of elements making up PM2.5.5 on haze days and non-haze days,the concentrations of elements in haze days was much higher than that in non-haze days.The total concentration of elements on haze days?855.10 ng/m3?was 2.26 times than the total concentration of elements on non-haze days?378.07ng/m3?.Especially for elements Al,As,Cd,Cr,Pb and Ti,the concentration of haze days is more than 2.5 times than non-haze days,and most of these elements are pollution elements.?4?The concentration of PM2.5.5 has a high correlation with Air Quality Index?AQI?in Shanghai,with correlation coefficient of 0.75,which indicated that PM2.5.5 was the main pollutant in atmospheric pollution in Shanghai.Atmospheric conventional pollutants has a great influence on the total concentration of elements,the crustal elements and pollution elements in PM2.5,especially for pollution elements.From the correlation coefficient,the correlations between the total concentrations of PM2.5?crustal elements and pollution elements?and PM10,NO2,SO2,CO,AQI were greater than 0.7,showing significant correlation.?5?The results of Enrichment factors?EFs?showed that the EFs of Al,Si and Ti were than 1,not enriched,and those elements were mainly affected by the crustal source.The EFs of Cr,Ba,Mn,Ni,P and V were between 14.08 and 80.45,indicating that besides the crustal source,these elements are also affected by anthropogenic sources.The EFs of As,Br,Cd,Cu,I,Pb,Sb,Se and Zn were between 183.82 and133063.92,which were significantly enriched relative to the crust.These elements derive mainly from pollution sources such as fossil fuel combustion and industrial sources.The results of correlation analysis and principal component analysis?PCA?showed that the elements such as Al,Si,Ti and P in PM2.5.5 mainly come from the crustal sources such as dust and soil fly ash.Elements Zn,Cu,Cr,Cd,Se and Pb are mainly from industrial sources such as ferrous metallurgy.Elements Ba and Mn are affected by crustal sources and anthropogenic sources.Ni and V elements are mainly from fossil fuel combustion. |
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