A series of salt fog and UV aging tests were performed on non-ceramic insulators with different polymeric housing materials. The samples from the insulator housings were characterized before arid after the aging tests using analytical techniques of X-ray photoelectron spectroscopy (XPS) and Fourier transform infra-red spectroscopy (FTIR). It was found that there is a change in elemental composition on the surface layer between the aged and non-aged samples. The change depends on the materials of the insulator housing and the aging test parameters employed.