A qualitative study of atmospheric aerosols and particles deposited on flat membrane surfaces by microscopy and other techniques

Samples of atmospheric particulate matter placed on Nuclepore® filters were analyzed by microscopy and complementary techniques. Volcanic ash placed on glass surfaces and atmospheric material on Teflon® filters were also studied by microscopy. The analyzed samples are related to volcanic eruptions, urban environments, and mining activity. Nuclepore filters are thin sheets with smooth surfaces on which particles are fixed almost uniformly after filtration, which makes them especially adequate for study by microscopy. Here a selection of samples analyzed by microscopy is presented, along with information on the shape and size of particles and their distribution on the surface of the filter. Hypotheses are advanced on the origin of particles, their crystalline states, and the physical mechanisms to trap particles on the filter surface. A morphological classification of the particles was carried out according to their appearance in the several samples analyzed. Other complementary analyses performed by PIXE (particle induced X-ray emission), by electron microprobe, by X-ray diffraction and by granulometry, are commented. The implications of the particles studied to human health are also discussed.