Magnetism Parameters Change In Space-Time And The Significant In Environment Of Street Dust In Jin Hua

As accelerating economic development and urbanization, the city has become the most intimate relations with the environment and concentrated area of human contradiction, the urban environment problem increasingly prominent, urban particulate matter pollution has become one of the important environmental issues in global and a serious threat to the health and survival of urban residents with the development of the city; Street dust is dispersed in the surface of solid particles in different areas of the city, being the main source of indoor dust pollution and urban atmospheric particulate matter, containing heavy metals and the source and sink of polycyclic aromatic hydrocarbons and other pollutants, indicating the urban ecological environment to some degree.Urban dust research began in the mid of 1970s, the geochemical methods have been widely used in city street dust in the study.But the method analysis cycle is long, high cost; Relative to character, environmental magnetism due to its simple, quick and no damage of the sample by many researchers used to analysis the advantages of street dust. Proposed in this paper through to the jinhua city different functional areas, road area, land cover area is sampled points, street dust samples collected, through the analysis of the environmental magnetism parameters, comprehensive analysis of characteristics of dust samples of magnetic parameters and their environmental implications, carries the results showed that:(1) The year average of X is 340.35×10-8m3·kg-1, change the range in 89.49×10-8853.91×10-8m3-kg-1, the variation coefficient is 0.405, with magnetic enhancement effect; Average frequency of magnetic susceptibility was 1.475%, the range from 0.07% to 4.24%, the variation coefficient is 0.64, the highest and the lowest is large:Winter season (January) average of X:322.55×10-8 m3·kg-1, spring (4 months) season average of X 358.16×10-8 m3·kg-1.the summer season (sep) average of X：368.31×10-8 m3·kg-1.the autumn season (November) average of χlf:324.13×10-8 m3·kg-1.the variation coefficient were 0.41,0.38,0.4,0.43; The value of four seasons was high, indicating have magnetic enhancement effect, in which season, between minimum value during the winter, the summer’s biggest; Frequency magnetic susceptibility average is 1.55,1.58,1.18 and 1.55, respectively, the variation coefficient was 0.63,0.6,0.68 and 0.63, respectively, mean and coefficient of variation is very close, there is not much difference; Jinhua city street dust of magnetic susceptibility and frequency magnetic susceptibility is negatively related to the basic relationship between χlf and χfd%.(2) From the year analysis:jinhua street dust saturation isothermal remanent magnetism SIRM changes in the range of 1910.17×10-5-12631.4×10-5 Am2·kg-1, with a mean of 5576.68 ×10-5 Am2·kg-1, the variation coefficient is 0.52. the variation coefficient is higher, reveals the jinhua city street dust samples, incomplete antiferromagnetic and the ferrous magnetic mineral content is more, single domain magnetic particles particle concentration. Jinhua city street dust sample source of magnetic minerals is single; The hysteresis remanence χARM change range of 11.64×10-8～2001.58×10-8 m3·kg-1, with a mean of 426.78×10-8 m3·kg-1, the variation coefficient is 0.74, the variation coefficient is higher, larger changes in season, stable effect of the content is higher in the sample, magnetic mineral content is higher, with magnetic enhancement effect, with ferrous magnetic minerals and incomplete antiferromagnetic minerals mainly.(3) Other magnetism parameters:S ratio change interval is 0.65～1.95, the mean is 0.97, the variation coefficient is 0.08, that street dust samples is more, soft magnetic component in ferrous magnetic minerals of main parts; SIRM/χlf changes in the range of 4.64×103～4.64 ×103m·A-1, the average of 17.53×103m·A-1, the variation coefficient is 0.56, can partly explain almost does not contain superparamagnetism granule in the sample, and the particles are relatively thin.χARM/SIRM and χARM/χlf mean value were 0.09×10-3mA-1 and 1.49, manifests further jinhua street magnetic mineral particles are fine dust samples, ferrous magnetic mineral content is given priority to; Magnetism parameters analysis, the spatial distribution of high value area is concentrated in the industrial zone, traffic concentration areas intense area and other human activities, seasonal differences are mainly concentrated in summer and fall, high value that is different from the north city street dust research.(4) SIRM in 0.03 um and around 50 um, there are two peak, while XARM only has a peak in 0.03 um, namely SIRM has main effect with thicker for sensitive mineral,XARM to stabilizing effect and a finer prospective effect is more sensitive,SIRM fall lowest value,XARM highest value in autumn; At the same time, the higher SIRM/XIf、XARM/SIRM、XARM/XIF the value is, which indicates that magnetic mineral particles in the sample is fine, and three parameters occurred in the autumn, the highest showed that autumn magnetic mineral composition in the sample is given priority to with a finer particles, so presumably jinhua street dust fall a major contribution to increased susceptibility components shall be the stability of the grain size in the vicinity of 0.03 um single domain or prospective effect.(5) The remanent magnetism saturation isothermal remanent magnetism parameters SIRM and the hysteresis remanent magnetism of magnetic susceptibility XARM and strong linear positive correlation, therefore the relationship between magnetic susceptibility and regional factors and the relationship of the remanence and regional factors consistent, magnetic susceptibility can better instruction significance.(6) The jinhua street intersection of magnetic susceptibility is higher than the crossroads, main road, the road network density of magnetic susceptibility in the region of the small area above the main road, road network density; Dust of magnetic susceptibility and road network density were positively correlated. Transportation (including traffic behavior and traffic flow) is a key factor in jinhua city street dust of magnetic susceptibility, jinhua street dust the surface of magnetic susceptibility can indicate the jinhua urban traffic pollution condition; Jinhua city street dust magnetic susceptibility of the high value area and the distribution of urban industrial zone, combined with analysis of model parameters, industry is one of the factors lead to the enhanced effect of dust produce magnetic, magnetic susceptibility of jinhua city street dust and good enough to explain the phenomenon of regional factors interact with each other in the study area, can effectively reflect the distribution of dust and pollution.