Utilization of polymer products for outdoor applications is continuously increasing. So the stability of polymers against environmental degradation became top of interests for many researchers. The effect of environmental elements on the polymers stability has been studied, but individually. A solution against an environmental element may conflict with a solution against other element. Therefore current study aimed to clarify a sort of these conflicts, by successive exposure of low density polyethylene (LDPE) films to acid rains and ultra violet (UV) radiation for different times. The used LDPE films are selected from the commercial grads which are used for plants greenhouses, in order to use samples fully protected against environmental elements. It is found that acid rains etch PE films, causing removal for some of the UV stabilizer additives, and hence UV radiation could attack PE films seriously causing remarked oxidative degradation. This study includes wide comparisons between effects of acid rain only, UV irradiation only, acid rain followed by UV irradiation and UV irradiation followed by acid rain exposure. Variations in the chemical composition, morphological structures, thermal and mechanical properties are detected by the IR- spectroscopy, X-ray diffraction, differential thermal analysis (DTA) and tensile tests. A new view for the differentiation between degradations caused by acid rains and UV radiation is discussed. Lot of experimental data are given in many coloured graphs and tables.