Online mass spectrometric aerosol measurements during the MINOS campaign (Crete, August 2001)

[摘要] Mass spectrometric analysis of volatile and semi-volatile (=non-refractory) aerosol particles have been performed during afield study in the summer Eastern Mediterranean. A size-resolved, quantitative mass spectrometric technique (the Aerodyne AerosolMass Spectrometer, AMS) has been used, and the results are compared to filter sampling methods and particle sizingtechniques. The different techniques agree with the finding that the fine particle mode(D<1.2 mm) consisted mostly ofammonium sulfate and of organic material. The aerosol sulfate ranged between 2 and12 mg/m³. On most days, ammonium wasclosely correlated with sulfate, suggesting ammonium sulfate as the major aerosol component, but on days with high sulfate massconcentrations, the sulfate was not fully neutralized by ammonium. Trajectories indicate that the aerosol and/or its precursorsoriginate from South-Eastern Europe. The source of the ammonium sulfate aerosol is most likely fossil fuel burning, whereas theorganic aerosol may also originate from biomass burning. Ion series analysis of the organics fraction in the mass spectrometerindicated that the major component of the organics were oxygenated organics which are a marker for aged, photochemically processedaerosol or biomass burning aerosol. The non-refractory aerosol compounds, measured with the Aerosol Mass Spectrometer,contributed between 37 and 50% to the total aerosol mass in the fine mode. A second mass spectrometer for single particle analysisby laser ablation has been used for the first time in the field during this study and yielded results, which agree with filtersamples of the coarse particle mode. This mode consisted of sea salt particles and dust aerosol.

[学科分类] 大气科学