| To exploring the seasonal variation and source apportionment of soluble ion and elements in PM10, PM2.1and PM1.1, two large-scale esperiments were conducted. First experiment, the aerosol mass concentration and elements, soluble ion concentration were investigated during one-year observation from2010-5～2011-4in urban-district and north suburb in Nanjing. And the second experiment, the aerosol mass concentration and soluble ion concentration were investigated during one-year observation from2012-10～2011-7in five cities in Yangtze River Delta. As the results shows:(1)①The concentration of PM10, PM2.1, PM1.1were sequentially winter>spring>autumn>summer. In spring, summer and autumn, the concentration of PM10, PM2.1, PM1.1in north suburb were higher than in urban, while winter opposite.②SO42-，NO3-, Ca2+, NH4+, Cl-, K+, Na+, F-, NO2-, Mg2+were measured, and their total concentration in PM10was46μg·m-3in urban sites and39.6μg·m-3in north suburbs. Mass fraction percentage of water soluble ions in PM2.1-10, PM1.1-2.1, PM1.1in urban district increased from20.4%to49.5%and56%, and which in north suburb increased from18.3%to37.9%and42.5%.③Major ions, SO42-, NO3-, NH4+, second components and Ca2+have significant seasonal variation. In urban district, highest concentrations observed in winter, lowest in summer, while in north suburb, highest concentrations observed in spring, lowest in summer. The seasonal changing climate in Nanjing and different anthropogenic influences with land surface in urban-suburb may be the major factor to ions’seasonal variation.④NH4+SO42-, NO3-came from second chemical reaction by NH3, NOX, SO2, and these precursors came from verticals mostly in Summer while came quite from verticals and fossil fuel. Cl-came from biomass burning in Winter while transported from sea salt with Na+in Summer. Ca2+and Mg2+came from ground dust and construction dust. K+, F-, NO2-may come from biomass burning and industrial emissions.⑤The concentration of PM2.1and soluble ions continuing incresead to high reval until cold front. The moving emission sources made the pollution procession。 precipitation following the cold front decreased concentration of ions while increased their percentage accounted for PM2.1,which indicated precipitation scavenging on the clearance of soluble ions was weaker than the other ingredients⑥Litter change of Particular concentration from2010to2013in Nanjing, while the concentration ang percentage of soluble ions overall increased. SO42-concentration deceased, and the ratio NO3-/SO42-in PM2.1and PM2.1～10rosed from1.01to1.32, and from1.17to3.78respectively. The moving source emission has substituted stationary sources to being the dominating emission source of atmosphere pollution.(2) Ca、Fe、K、Al、Na、Mg, these earth elements have higher concentration of size three segments, similar to the outskirts concentration accounting for PM2.1～10, PM1.1～2.1, PM1.1deceased from17.3%to7.6%,5.8%. EF facter indicated that Ca came from natural sources in PM2.1while from anthropogenic source in PM2.1～10, K in PM2.1mainly came from plant emissions and burning crops, and natural source produced number of K. Pb, Zn, As were from anthropogenic sources in all diameter section, and enrichment in PM2.1was10～20times than in PM2.1～10.Cu, Co, Ni were from anthropogenic sources in all diameter section, and enrichment in PM2.1was4～5times than in PM2.1～10.(3)①The concentration of PM10, PM2.1, PM2.1and the ratio PM2.1/PM10in Yangtgze River Delta cities were sequentially winter>spring>autumn>summer. PM10and PM2.1in Hangzhou were lowest in YRD. The peak concentration in0.43～0.65μm in Suzhou and Ningbo were significantly lower than other cities.②The proportion of ions were close to50%in Nanjing, Suzhou, Hangzhou, Ningbo, and44%in Lin’an. SO42-, NO3-NH4+were three three major pollution ions ions in PM2.1, occupy80%of the total ions in cities, and occupy90%of which two sampling sites in Ningbo. The ion proportion of PM2.1～10were close to30%in Nanjing, Suzhou, Hangzhou, and close to20%in Lin’an, Ningbo. Ca2+, SO42-, NO3-were major ions, concentrations of them occupy70%of total ions.③In PM2.1, SO42-, NO3-, NH4+had highest concentrations observed in winter, lowest in summer, K+, Cl", had higher concentrations in Autumn. Ca2+, Mg2+in cities had similar seasonal trend highest concentrations observed in spring, lowest in winter.④Mg2+were affected by sea salt in PM2.1while affected by local sources in PM2.1～10. Nss-Cl-/Cl-in PM2.1～10was lower in Winter and Spring, about40%, and higher in Summer with the60%. Nss-Cl-/Cl-in PM2.1～10was lower than in PM2.1. Non-sea salt component of NO3-, NH4+, Ca2+were overall as high as99%. |
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