Lianyungang Coastal Atmospheric Water-soluble Anion,

Economic losses caused by corrosion of the industrial facilities and machineries by the salty marine atmosphere has become a major problem in the coastal regions of China in recent years. Of particular concern are the corrosion problems exist in nuclear power plants because of the serious environmental and health implications involved. Atmospheric anions are the ones responsible for most of the corrosion problem in marine air. Thus, to gain better understanding on the physiochemical properties, the transport and the environmental fate of atmospheric anions is important for corrosion control through the selection of proper materials, the development of preventive methods, and the design of effective anti-corrosion technologies.During the study period from June 2005 to May 2006, a total of 594 Atmospheric Absorb Solution(AAS) samples, 300 Total Suspended Particle(TSP) samples, 114 Wet Deposition(WD) samples and 36 Dry Deposition (DD)samples were collected at Tianwan nuclear power plant in the Lianyungang coastal region. The water soluble inorganic anions (Cl^-,NO₃^-,SO₄^2-) in each of these samples were analyzed by Ion Chromatography (IC). The results and discussions in the thesis is organized into the following five chapters:In Chapter 1, the methods and trends in the research of atmospheric chemical compositions such as water soluble ions, heavy metals and organic compounds are reviewed. The objectives of the study are also described in this part.Chapter 2 discusses the experimental aspects of IC, including instrumentation, reagents usage, operational conditions, the detection mechanism and data processing routines.Chapter 3 presents the concentration levels and seasonal characteristics of three water soluble atmospheric inorganic anions, AAS, TSP, WD and DD, and the quality control practices in these measurements. The results show that the concentrations of the three water soluble inorganic anions in AAS, TSP and WD and DD follow the same trend: SO₄^2- > Cl^- > NO₃^-. The concentrations of these pollutants show notable seasonal variations : the concentrations of Cl^- and SO₄^2- in AAS are higher in summer and lower in winter; the concentration of NO₃^- is higher in autumn and lower in summer; the quality concentration of TSP is higher in spring and lower in summer; the concentration of Cl^- in TSP is higher in spring and autumn; but lower in summer and winter; the concentration of NO₃^- and SO₄^2- are higher in winter and spring but lower in summer and autumn; the concentration of NO₃^- and SO₄^2- in WD are higher in winter and spring but lower in summer and autumn; the concentration of Cl^- is high in autumn and winter but lower in spring and summer; the concentration of Cl^- and SO₄^2- in DD are higher in summer but lower in winter; and the concentration of NO₃^- is higher in spring and autumn but lower in summer and winter.The results of correlation analyses show the existence of good correlations between SO₄^2- and Cl^-, and SO₄^2-and NO₃^- in AAS. However, the correlation coefficient between Cl^- and NO₃^- is lower. This suggests that SO₄^2- may have the same source as Cl^- and NO₃^- during different seasons. However, Cl^- and NO₃^- likely to have different sources. In TSP, there is a good correlation between Cl^- and NO₃^-, and also between NO₃^- and SO₄^2- . There are also good correlations between Cl^-, NO₃^-, SO₄^2- and the mass concentration in TSP. Good correlations exist between both NO₃^- in AAS and both NO₃^- and SO₄^2- in TSP. Good correlations also exist between SO₄^2- in AAS and both NO₃^- and SO₄^2- in TSP. These results illustrate that NO₃^- and SO₄^2- in both AAS and TSP may have the same sources. Negative correlation exist between Cl^- in AAS and mass concentration of TSP. This is mainly because that Cl^- in the atmosphere is affected highly by ocean, however the aerosol mainly comes from droughty region inland. Good correlations exist between NO₃^- and SO₄^2- in WD; negative correlation exist between rainfall and both NO₃^- and SO₄^2- in WD. This indicates that these ions mainly come from the dissolution of aerosols and acidic gases in the atmosphere. During heavy rainfall, the water volume increases, resulting in lower concentrations of acidic anions in WD.Chapter 4 summarizes the effects of meteorological parameters to the concentration of water soluble anions in Lianyungang. The parameters studied include wind direction,wind speed,relative humidity,temperature,air pressure,water temperature surface layer inshore,wave height, and rainfall. Correlation analyses have been made between water soluble anions and each of the above meteorological parameters. Among the parameters studied, wind direction,temperature, water temperature surface layer inshore,humidity and air pressure are the ones affecting the anion concentrations the most.Major conclusions are summarized in chapter 5.