The Statistical Characteristics Of Air Pollutant Concentrations And The Relationships Between Meteorological Elements And Pollutants In Yulin, Shaanxi, China

This paper analyses the statistic characteristic of three kinds of basic atmospheric pollutants(SO2、NO2 and PM10) in Yulin city,china, based on the time series of the data of air pollutant concentration by Yulin Environmently monitory station. The main conclusions are listed as follows:1. On the basis of Time Series Analysis of the concentration of SO2、NO2 and PM10, the results show that the seasonal and diurnal variations of of three kinds of air pollutants in the hourly concentrations are very clear. The concentration is the highest in spring and winter, higher in autumn, and declines to the lowest in summer. The change tendency of SO2 is similar with PM10 about the hour concentration, presenting two-peak and two-valley, while NO2 shows single valley pattern(the lowest concentration at noon, and the highest concentration at night and after-dawn than pre dawn).2. The spatial distribution of air pollutants depend on contaminant characters, and the wind speed and direction. Therefore, the hourly concentrations of SO2、NO2 and PM10 also shows special spatially distribution, as follows. In terms of SO2 and NO2, Experimental Middle School is the highest, Redstone gorge is the lowest in SO2 and Century Square in NO2. However, the highest concentration of PM10 appears in Environmental Protection Building, the lowest in Century Square.3. Four types of statistical distribution model i.e.Log-logistic distribution, Logarithmic normal distribution, General extreme value distribution and Weibull distribution, are selected to analyze the hourly concentrations of three kinds air pollutants( SO2、NO2 and PM10). More important, we confirm and establish the optimal distribution model and related parameters about every pollutant. Finally, we evaluate the fitting degree between concentrations and goodness-of-fit test method, i.e. KS, AD and Chi-squared, respectively.4. The relation between air pollutant concentration and meterorolgical factors is researched through linear correlation analysis method. The results show that among some factors, temperature and mixed layer height present a negative correlation with air pollutant concentration; while the pressure and atmospheric stability have a positive correlation. And the wind speed shows a negative correlation with SO2 and NO2 concentration and a positive correlation with PM10 concentration.