南京秋冬季非难熔性亚微米颗粒物来源解析

Chemical composition characteristics and source of non-refractory submicron aerosol in autumn and winter in the northern suburbs of Nanjing

利用Aerodyne高分辨率飞行时间气溶胶质谱仪(HR-ToF-AMS)对南京北郊秋冬季非难熔性亚微米气溶胶(NR-PM_(1))的化学组分(包括有机物、硝酸盐、硫酸盐、铵盐和氯化物)和特征进行实时在线监测,并利用多元线性模型(ME-2)对其中复杂的有机物进行来源解析.观测期间,有机物、硝酸盐、硫酸盐、铵盐、氯化物对NR-PM_(1)的贡献分别为42%,28%,15%,13%和2%.有机物解析出6类有机气溶胶:烃类有机气溶胶(HOA)、烹饪类有机气溶胶(COA)、生物质燃烧有机气溶胶(BBOA)、高氧化有机气溶胶(MO-OOA)、低氧化有机气溶胶(LO-OOA)、液相反应生成氧化有机气溶胶(aq-OOA),平均浓度分别占总有机气溶胶的18%,14%,19%,19%,11%和19%.通过不同污染事件的对比结果表明,本次观测期间二次气溶胶在污染时期占比会明显上升并且液相反应对二次组分的形成有显著的促进作用.

In this study,Aerodyne high-resolution time-of-flight aerosol mass spectrometer(HR-ToF-AMS)was used to monitor the chemical components(including organic matter,nitrate,sulfate,ammonium and chloride)and characteristics of non-refractory submicron aerosol(NR-PM1)in autumn and winter in the northern suburbs of Nanjing,and PMF&ME-2(positive matrix factorization&multilinear engine)source analysis mode was used to identify sources of complex organic compounds.During the observation period,the contributions of organic matter,nitrate,sulfate,ammonium and chloride to NR-PM1 were 42%,28%,15%,13%and 2%respectively.Six types of organic aerosols were identified:hydrocarbon like organic aerosol(HOA),cooking related organic aerosol(COA),biomass burning organic aerosol(BBOA),more oxidized organic aerosol(MO-OOA),less-oxidized oxygenated organic aerosol(LO-OOA)and aqueous-phase-processed oxygenated organic aerosol(aq-OOA),and their average concentrations accounted for 18%,14%,19%,19%,11%and 19%of the total organic aerosols,respectively.The results of comparing different pollution events show that the proportion of secondary aerosol will increase significantly during the pollution period,and the liquid phase reaction can significantly promote the formation of secondary components.