The Analyses Of Chemical Characteristics Of Fog Water In Nanjing In Winter

In this paper,we use fog samples of there fog collected on November 30 to December 30,2006 in Nanjing and information with the same times rain samples and the fog droplet spectrometer observation of micro-physical structures and detection of balloon in the boundary layer information to analyze the pH of the fog,chemical composition and the relationship between them and the macro-physical and micro-physical structure and the characteristics of the change of the chemical compounds during the fog.The results show that:the frequency of acid fog is 47%; the average pH is 5.86;the main cation in fog are NH₄⁺,Na⁺,Ca²⁺;the first main anion is SO₄^2-,NQ₃ and the second is Cι^-;the concentration of total ion and SO₄^2-is high,which show that the Air pollution in Nanjing is very serious.Na⁺ /Cι^-in fog water is 2.75,which significantly higher than in other regions.The significant loss in Cι^-,which mainly because the fog is advection - radiation fog affected by the winds of the southeast warm advection.There some conclusions for the third fog.The ion concentration and fog droplet size is related to the anti-trend(r =0.71).In the fog process,the pH first increase then dropped,which occur three times and the trend with the ions and ion concentration in the general is contrary.The ion of fog-water concentration of the general trend is increasing in entire process of the fog,mainly because of the inversion layer has always existed in the course of fog.The main cation in rain areCa²⁺,Na⁺,NH₄⁺,the main anion is SO₄^2-, Cι^-,NO₃^-;the average pH is 5.27;the average conductance is 76.8μs/cm.The ion concentration in fog water is much higher than in the rain,but the fog is much more acid than rain.We compare the results of acid rain on several occasions in Nanjing history,find that overall trend of the pH value of rainfall is the volatility of decline, the minimum pH value is also a downward trend,the frequency of acid rain becomes larger.Those show the acid rain that more and more serious and environmental pollution has aggravated in Nanjing.