Study On Several Issues Concerning Urban Pollutants

Compared with the changes in the concentration of urban pollution characteristics of a contrast on the weather conditions on the concentration of pollutants changes and the law in Beijing and Nanjing in winter, analyzed the impact and tracked patterns of research using the track model; fog water from the Nanjing Chemical analysis of data based on the urban pollutants on the impact of weather phenomena which happed in city, the main findings are as follows:Firstly, City study find that aerosol particles in the atmosphere, through the heterogeneous chemical reactions, affect the atmosphere changes of the pollutant gases in the atmosphere changes to a large extent. Beijing observational data analysis find that cities in the PM₁₀ and PM2.5 and O₃ significantly change the concentration of the anti-correlation, model studies show that different types of aerosol particles, the different effects of air pollutants are not the same, even in different ratio of NMHC / NO_X, impact of aerosol pollutants on the pollutant gases are different.Secondly, By utilizing the ground atmospheric concentrations of major pollutants of observational data from 12,2007 to 3,2008 in Nanjing ,a analyzed the SO₂, O₃ and its precursors NO, NO₂ concentration and distribution of the changes in the law. The results show that in Nanjing concentrations of O₃ and SO₂ are significantly changes, photochemical pollution is much serious; O₃ concentration on the 1st of a single peak of the obvious changes, O₃ and its precursors NO, NO₂ concentration, significantly change the anti-related , SO₂ is a double-change. In addition to the impact of human activities, weekend city's major pollutants in the atmosphere SO₂, NO, NO₂ and O₃ concentration on changes in the law and working day is different.Thirdly, compared with atmospheric pollutants NO, NO₂, and the changes of O₃ in winter between Nanjing and Beijing, which find the main city in winter in Beijing and Nanjing. There is a similarity of pollutants, but although Beijing in the atmosphere ozone precursors NO and NO₂ concentration higher than in Nanjing, but in the atmosphere ozone concentration is higher than in Beijing. The effects of different weather conditions, changes in urban concentration of pollutants, found that the strength of solar radiation on the concentration of pollutants there is a clear impact. In addition, the air stability and precipitation process will cause the concentration of pollutants in the atmosphere changes. HYSPL1T-4 to track patterns which ozone above the standard level in Nanjing find that the main characteristics of the airflow into orbit: the northern industrial zone of influence, the impact on the surrounding city and regional combining local effect.Fourthly, To investigate the chemical composition of fog water in Nanjing, the data collected from a field observation are analyzed, compared with the chemical composition of rain water obtained in the same month. The pH value of the fog water in Nanjing ranges from 4.24 to 7.27, and most of the fog water is acid. The chemical compositions of rain and fog water and their changes have a great similarity. In order to further identify the chemical characteristics of fogs, the data were analyzed to determine: the correlation coefficient of fog ions and the relationship between the changes of ion concentration and the gaseous pollutants, the conductance and PM₁₀. The analysis show that peak values in the ion concentration of fog water are closely correlated with the macro-physical and micro-physical characteristics of fogs. It also shows that the changes of the chemical compositions of fog and the polluted air have a great similarity. This study shows that the air pollutants have important impaction on weather phenomena which happen in the city.