Microscopic characterization of individual particles from multicomponent ship exhaust.

Particles sampled from the main and auxiliary ship diesel engine exhausts during a measurement campaign aboard a cargo ship are studied by SEM and energy-dispersive X-ray (EDX) microanalysis. Cluster analysis (CA) is applied to characterize the particles by separating them into distinct groups of similar morphology and chemical composition, representative of the particle types in the exhaust from the main and auxiliary engines. Raman microspectroscopy, Fourier transform infrared (FTIR) spectroscopy, inductively coupled plasma mass spectrometry and ion chromatography provide the criteria for the clustering of a large data set of individual particles.

Water interaction with hydrophobic and hydrophilic soot particles.

The interaction of water with laboratory soots possessing a range of properties relevant for atmospheric studies is examined by two complementary methods: gravimetrical measurement of water uptake coupled with chemical composition and porosity analysis and HTDMA (humidified tandem differential mobility analyzer) inference of water uptake accompanied by separate TEM (transmission electron microscopy) analysis of single particles. The first method clarifies the mechanism of water uptake for bulk soot and allows the classification of soot with respect to its hygroscopicity. The second method highlights the dependence of the soot aerosol growth factor on relative humidity (RH) for quasi-monodisperse particles.