Characteristics Of Air Suspended Particulate Matter In Huainan And Monitoring Pollutant By Trees

With a sharp increase in industrial activities, urban population, and city vehicles, air pollution inurban became serious. The first airborne pollutant transferred from SO2to particulate matter（PM）. The adverse effects on human health due to inhalation of PM₁₀and PM_2.5, as well as heavymetals contained in PM such as cadmium, lead, chromium, copper, nickel, and zinc have beenidentified. It is primary work to monitor concentration of inhalable particles and heavy metals inenvironmemtal practice. Assessment of environmental pollution by plants has been proved to bea convenient method of pollutant analysis. And tree leaves have been used as bioindicators ofatmosphere heavy metal pollutants in numerous studies. Physico-chemical characteristics andemission sources of inhalable particles were analyzed in Huainan, Anhui, China. Correlationamong daily average mass concentration of PM, content of heavy metals in PM, and content ofheavy metals accumulated in leaves of Platanus acerifolia was investigated in this study.Variation in PM absorption and metal accumulation and physiology response to traffic pollutionwas documented for leaves from seven tree species. A spatial pattern in distributions of heavymetal pollution indicated by P. in Huainan was recognized in this paper. The main results are asfollows:（1） PM₁₀and PM_2.5samples were collected at six sites accounting for major environmentalfeatures in Huainan during one year. Various approaches, such as Analytical Balance andInductively Coupled Plasma Optical Emission Spectrometer, were used to analyzephysico-chemical characteristics and sources of airborne particles. The results indicaed aremarkable pattern of spatial-temporal variation in pollution levels of PM₁₀and PM_2.5. PMconcentrations in winter and spring were much higher than the other seasons, and summer wasthe lowest season in PM concentrations. Significant difference were found among sample sites inmass concentration of PM₁₀and PM_2.5,ratios of fine to coarse PM, element concentrations in PM,and kinds of leading elements. Elements with higher enrich factors （EF＞10） were characterizedas Cd, Cr, Cu, Ni, Pb and Zn from18elements measured. EFs of elements in fine PM werehigher than those in coarse PM. The sources of PM₁₀and PM_2.5were coal burning, road dust andexhaust caused by vehicle.（2）Daily variation and daily mass concentrations of TSP, PM₁₀, PM_2.5and contents of heavymetals in TSP were compared between clean and polluted sites. Correlation among PM diameterdistributions, heavy metal contents in PM, and heavy metal contents in leaves of P. acerifoliawere analyzed respectively. The results revealed a rekarkbly high measurement in daily averageconcentration of TSP, PM₁₀, PM_2.5, within air-polluted coal-mine, with half data higher than thethreshold value in GB3095-2012. Zn and Pb were the dominant elements of heavy metals incoarse PM, while PM_2.5 was the main fraction of PM. Contents of heavy metals accumulated inleaves of P. acerifolia in coal-mine were higher than those in none coal-mine, positive correlationof heavy metal contents between TSP and leaves of P. acerifolia was found, indicating the highercorrelation coefficent the severer environmental pollution. Moreover, contents of six heavy metals in P. acerifolia were positivly correlated with mass concentrations in PM_2.5.（3）Seven tree species, such as Ginkgo biloba, at dense heavy traffic site in Huainan were selectedto analyze the effects of leaf micro-morphology on PM diameter frequency retained by leavesand particle amount of different sizes per unit leaf area,as well as relationship between particleamount of different sizes per unit leaf area and content of heavy metals. We found that thespecies characterized by small leaf area, special epidermis with abundant fax and highly unevencell wall, without trichomes as well as big and dense stomata mainly absorbed fine particulatematter; while those species with dense trichomes mainly retained coarse particulate matter.Accumulation of heavy metals in leaves of seven species was significantly different except Pb.Tree species with high capacities in heavy metal accumulation were G. biloba, Ligustrumlucidum, and Cinnamomum camphora. Accumulation of Cd, Cr, Ni, Zn, Cu and totalconcentrations of five elements were positively related to amount of particulate matter ofabsorption. Correlation coefficients of d10vs d2.5, d10vs d1.0, d2.5vs d1.0were0.987,0.971,and0.996respective, the correlation level were significant. The ratios of d2.5/d10, d1.0/d10,d1.0/d2.5were0.844,0.763, and0.822, thus particulate matter from traffic was mainly the finekind.（4） In order to select suitable species for transportation pollution monitoring, some representativetree species occurring in the arterial roads and the roads of a forest park in Huainan were chosento systematically study accumulation patterns in heavy metal elements （Cd, Cr, Cu, Ni, Pb andZn） and variation patterns in physiological indexes （MDA, souble sugar and SOD） in leaves bychemical analysis method and physiological index determination method. The results showedthat the heavy metal contents in the arterial roads were significantly greater than thos in the forestpark, which meaned transportation pollution was becoming more serious. Meanwhile, MDA,souble sugar and SOD levels on the arterial roads suffering from transportation pollution weremuch higher than forest park roads in general as well. According to the physiological indexes andheavy metal content differences, C. camphora, L. lucidum, P. acerifolia, and G. biloba arefounded as fine species for transportation pollution monitoring. Besides, their functional typeswere divided based on relatively difference percentage of tree species’ heavy metal content.（5） P. acerifolia planted in many sites of Huainan with strong PM-absorbing ability and goodphysioly-regulating capapcities were selected to analysis pollution paterns of heavy metals in42sampling sites, The relationship between the contents of heavy metals in the plants andenvironment factors were analyzed with average linkage cluster analysis method. The resultsindicated that the42monitoring sites could be divided into three groups with different degrees ofheavy metal pollution. GIS maps of the heavy metal contents were made. The map showed thatthere is a heavyly polluted belt in six heavy metals from SW-NE. The data of six heavy metals inP. acerifolia demonstrated a trend of heavy pollution in center, and light pollution in suburban ofHuainan. The sites with heavy pollution was in line with such areas as coal-mine, plant power,and heavy traffic.