Abstract: At the GIC4117 1.7 MV tandem accelerator of Beijing Normal University, an external beam PIXE/PIGE analysis facility was established, and the analysis method of thin samples was developed on the facility. The average and the lowest limits of detection (LOD） of multielement for the external beam PIXE analysis of 361 PM2.5 samples collected on Teflon membrane filters in 2010 were given, and compared with those of vacuum PIXE analysis. The results of external beam PIGE analysis of standard samples show that the LOD can be as low as 73.9 ng•cm^-2 and 198.9 ng•cm^-2 for F (using 197 keV γ-ray from ¹⁹F(p, p′γ) ¹⁹F reaction) and Na, respectively.