Characterization of Ambient Air Particle Size Fractions in Three GermanCities with the Aid of Electron Microscopy

Multistage-filtration samplers offer the opportunity toanalyze dust fractions deposited on corresponding stages of the sampler. Inthis investigation, a typical two-stage sampler was used in the cities ofDortmund (mining and steel industry), Dusseldorf (lesser industrialactivities), and Duisburg (steel industry), North Rhine Westphalia. Thepurpose of this study was to compare the composition of dust fractions withthe aid of analytical electron transmission microscopical methods. Theparticle size distribution was similar in the cities, the 50% value ofthe equivalent diameter was 0.8 μm. Analytical results are presented fordifferent mineral classes with approximately 30 single minerals in allcities. The highest concentration values in the fine dust fraction weresilicate minerals, while the sulfate content was very high in the coarse dustfraction in all cities.