Quantitative single-particle analysis with the Aerodyne aerosol mass spectrometer: development of a new classification algorithm and its application to field data

[摘要] Single-particle mass spectrometry has proven a valuable tool for gaininginformation on the mixing state of aerosol particles. With the Aerodyneaerosol mass spectrometer (AMS) equipped with a light-scattering probe,non-refractory components of submicron particles with diameters larger thanabout 300 nm can even be quantified on a single-particle basis. Here, wepresent a new method for the analysis of AMS single-particle mass spectra.The developed algorithm classifies the particles according to theircomponents (e.g. sulphate, nitrate, different types of organics) andsimultaneously provides quantitative information about the composition ofthe single particles. This classification algorithm was validated byapplying it to data acquired in laboratory experiments with particles ofknown composition, and applied to field data acquired during the MEGAPOLIsummer campaign (July 2009) in Paris. As shown, it is not only possible todirectly measure the mixing state of atmospheric particles, but also todirectly observe repartitioning of semi-volatile species between gas andparticle phase during the course of the day.

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