How a small accelerator can be useful for interdisciplinary applications: the study of air pollution

There are an increasing number of articles in the scientific literature dealing with the study of atmospheric aerosol because it has negative impacts on human health, atmospheric visibility and a role in the radiative forcing. Particle-induced X-ray emission (PIXE) has been used since its birth for the study of the aerosol composition, and for a long time, it has been the dominating technique for its elemental analysis. However, nowadays other competitive techniques play a dominant role, such as inductively coupled plasma–mass/atomic emission spectroscopy, energy-dispersive X-ray fluorescence and synchrotron radiation. Therefore, it is important to find specific applications where it can give unique information or the final results in a far simpler way. Furthermore, a proper experimental setup must be used to fully exploit the potential of PIXE. Thanks to the capability of detecting all the crustal elements, PIXE analyses are unrivaled in the study of mineral dust. Among the detectable elements, there are also important markers of anthropogenic sources, which allow effective source apportionment studies in polluted urban environments using multivariate methods. Examples regarding recent monitoring campaigns will be presented to show how PIXE is still on the cutting edge for the study of particulate matter.