| Aerosol becomes hotspot of study in recent years because of having an adverse impact on climate, environment, visibility and human being. Domestic and foreign researches carried out a lot of research on outdoor atmospheric fine particles and its chemical composition. Relatively speaking, Domestic researches carried out very little research on the indoor fine particles and its chemical composition. Particulate matter with aerodynamic diameters less than2.5μm (PM2.5) causes air quality problems in urban areas, especially visibility reduction and health problems, such as asthma and even mortality Water-soluble ions (ws-ions) are major components of the atmospheric aerosols, especially PM2.5, which compose up to60-70%of the total mass of suspended patriculate matter. Therefore, observations on the chemical composition of water-soluble fine aerosols would be valuable for understanding their chemical characteristics, sources, and behavior and formation mechanism. In order to reflect the NanChang PM2.5the pollution status, in this study, the choice of QianHu campus of Nanchang University as monitoring area. Using PM2.5comprehensive sampling, the ion chromatography research methods, research the mass concentration level, chemical composition, sources, etc. of PM2.5around QianHu campus of Nanchang University. Obtained as follows conclusions:(1) Higher levels of PM2.5and PM10concentration in winter than in summer, in winter the concentration of water soluble ions were higher than the summer. Particulate matter pollution situation was more serious in winter, and its chemical composition is more complicated.(2) The main caions and anions in both PM2.5and PM10were the same, these ions were:SO42-,NH4+, Na+,NO3-and Ca2-, accounting for93.1%of the total ion concentration and93.1%respectively, In PM10, the order of water-soluble ion concentration:SO42-> Na+> NH4+> Ca2+> NO3-> Cl-> K+> Mg2+, but in PM2.5, the order of water-soluble ion concentration:SO42-> NH4+> Na+> NO3>-Ca2+> Cl-> K+> Mg2+. SO42-in both coarse and fine particles were the highest concentrations of all kinds of water soluble ions,coarse particles and fine particle pollution in Nanchang mainly for sulfuric acid type.(3) In summer, but in winter, three ratio was less than60%, So SO42-, K+and NH4+in summer mainly enriched in fine particulate matter, and in winter may be due to the low winter temperatures and weak solar radiation, not conducive to the formation of secondary aerosols, while and do not change significantly in winter (60.0%and54.1%) and summer (56.5%and56.1%), suggests that these two ions mainly enriched in the coarse particles, and affected by the temperature change is small, but with dust, construction sites, motor vehicle activities have a close relationship.(4) This study:the concentration of three main water soluble ions (NH4+, NO3-and SO42-) in PM2.5in Nanchang was relatively high. There is even higher than both in domestic and foreign researches on concentration of particulate matter and ions, shows that Nanchang fine particulate matter pollution is quite serious;(5) In summer, the average concentration of most water soluble ions in fine particles at daytime were higher than at night, this result was mainly attributed to variations in the MLD (mixing layerdepth) between night and day.(6) The sampling study found that Nanchang mass concentration of PM2.5in the indoor environment (general office, printing room, dormitory, library, dining room and ordinary classrooms) is relatively high, even appeared higher than other research monitoring the concentration of particulate matter in similar environment. Nanchang fine particulate matter pollution is quite serious, need to timely take effective measures to control indoor particulate matter pollution, reduce the risk of exposure to fine particulate matter.(7) Indoor environment, multiple water soluble ion concentration is higher than outside, this due to human pollution sources, at these sites during the sampling could exist indoor source (such as smoking, experiment, day-to-day activities, etc.). Compared with the outdoor, indoor concentrations are relatively high qualities. And in winter, on the contrary, concentration of majority ions in the outdoor environment were higher than indoor environment, this is likely to be due to in the winter, doors and windows is basically closed, and indoor air has a lower exchange rate.(8) Ion balance calculation:the slopes (anion/cation) of the linear regression are lower than1in summer, but in winter the slopes (anion/cation) of the linear regression are higher than1, and the anion deficits are thought to have been affected by the absence of data on F-, PO43-, NO2-, CO32-and organic acid salt in summer. Relatively speaking, in winter the cation deficits are thought to have been affected by the absence of data on H+and other cations. Whether summer or winter, the sample sites01and12, the correlation of cations and anions is very good, shows that the two sampling sites of the anion and cation may come from the same source. |
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