Development and test of a passive sampler for fine particles
A horizontally mounted Teflon filter facing downwards was tested as a surrogate surface for sampling of fine particles in ambient air. The sampler was tested in Sweden and Nepal and compared to a vertically mounted filter. The particles collected on the horizontally mounted filter contained more nitrate, sulphate and ammonium. These ions can either be due to reactions between deposited particles with their gaseous precursors or deposition of fine particles. Calcium is mainly found in coarse particles. The calcium content of deposited particles were very similar in parallely exposed horizontally and vertically mounted filters indicating that large particles are also deposited on the sampler developed here. Another design of passive sampler is therefore suggested.