Hohhot Atmosphere Pollutant Characteristics And Air Quality Forecasting Methods Research,

This thesis gives an analysis on the features of spatial-temporal continuum distribution of air pollutants in the region of Huhehot according to the monitoring data from 1995 to 2002 about the density of such pollutants as PM10, TSP, NOx, NO2, and SO2 in the region. A further statistical analysis is made about the relationship between density of pollutants and meteorological conditions as well as the influence of weather prognostic field on the change of density of pollutants with the help of the data about baric topography of the corresponding period, and synoptic chart and meteorological parameter in atmospheric boundary layer, which accounts for the regular pattern of the change of density of pollutants, based on which a model is set up for statistical prediction of density of air pollution by adopting the method of progressive regression. Another numerical forecast model is set up on the basis of By using Fifth-Generation Penn State/NCAR Mesoscale nonhydrostatic Model. Finally, a comparative study is carried out on the advantages and disadvantages of statistical prediction model of air quality and the numerical forecast model.The above analysis shows that the dominant pollution in Hohhot is smoke pollution that is more serious in spring and summer than in winter and fall, and the same trend can also be observed in heating providing period and the period without heating. The density value of pollutants PM10, N02 and S02 shows obvious annual change with a decrease in density value of S02 year by year but an increase in PM10 and NO2 in recent years. There is one peak time in Monthly change (the greatest value in January and December, the lowest in July and August). Daily change shows two peak times in winter and summer with the greatest value appears between 8:00-10:00 and the value next to it between 20:00-24:00. In spring and fall, there arethree peak values in PM10 with the greatest between 17:00-18:00 and two values next to it between 1:00-3:00 and 8:00-1 l:00.Air particles form the primary pollutants and pollution is the most serious in residential area. In spring, summer and fall, density of pollutants is in inverse proportion to wind velocity. But in spring when wind velocity is greater than 2m/s, tlae density value of pollutant TSP is in direct proportion to wind velocity. When there is a rainfall between 1mm and 30mm, the density value of pollutants is in inverse proportion to rainfall. Total cloudiness and relative humidity are in direct proportion to the density of pollutants. The thicker inversion layer is, the greater the density is and inversion reaches its peak at 7 in winter. The thinner mixed layer is, the greater the density is and winter sees the thinnest mixed layer of a year in Huhhot. The serious pollution comes when the region of Huhhot is under continuous control by ground high pressure. Air appears to be of good quality as a result of the decrease in density value of pollutants, when Huhhot is in the front of the cold high pressure and the back of the cold front as cold air comes in.