The increasing use of plastics is accelerating their production, and the amount of plastic waste that often ends up in the environment is also increasing. Due to atmospheric influences and solar and UV radiation, plastic waste degrades and eventually turns into microplastics (MPs), thereby pose a threat to both humans and living and non-living nature. In this work, simulated UV aging of the polymer material polypropylene (PP) was performed at a radiation wavelength of λ = 290 nm and a temperature of 45 ± 1°C. Samples of PP films with a thickness of 0,2 cm were aged for 14, 28, 42, and 56 days. In order to monitor the degradation process, various characterization methods were used. Infrared spectroscopy (FTIR) was used to determine the values of carbonyl index (C.I.), which results from the degradation of PP molecules. Differential scanning calorimetry (DSC) was used to determine the melting point (Tm), crystallization point (Tc), and glass transition point (Tg), as well as the heat flows due to endothermic (ΔHm) and exothermic (ΔHc) transition and the degree of crystallinity (Xc) with aging time. The changes in morphology and surface properties of the aged samples were studied by scanning electron microscopy (SEM). Diffuse reflectance spectroscopy (DRS) confirmed the formation of oxidized C-O groups as a result of UV degradation of the polymer. Identification and concentration of residual metals were determined by inductively coupled plasma mass spectrometry (ICP-MS). The results indicate that UV aged sample released higher concentrations of metals compared to the non-aged samples, which can be attributed to the deteriorated structure as a result of degradation. The results of all methods performed indicate that the properties, structure, and chemical composition of the PP polymer molecules are changed with UV aging, leading to accelerating microplastic (MPs) formation.