I would imagine that it's practically impossible to remove or avoid given that pollen is all around us and the spores are measured in micro metres (µm or um). Perhaps you actually mean something like removing from clothes the stains that pollen (especially from lilies for example) cause? I think that can be tricky as some of this stuff acts like a dye. Lilies in particular are a bugger and it's quite possible that the stain cannot be removed.