The aim of this chapter is to summarize an experience with PIXE in analyses of aerosol samples. There are, of course, many papers on this topic, including notable reviews, because the analysis of aerosols is one of the most frequent applications of the PIXE technique. Most of the pertinent articles are listed in Chapter 12 of Reference 1, in which the state of the art in aerosol applications of PIXE is well described. Many papers appear in the regular conferences on PIXE and its applications. They have been held every third year since 1977, and their proceedings are published as special issues of Nuclear Instruments and Methods in Physics Research B. Nevertheless, some aspects of PIXE seem to be disregarded even though they are important in the interpretation of the data. Some of these aspects are discussed here.