UV Photodegradation / Polymer Chalking Contamination

UV-chalking contamination, it arises from photodegradation under ultraviolet exposure, where polymer chains fragment on the surface and thus form a white chalky residue that scatters and adheres as a powdery film. This residue distinguishes itself from dust or oxidation marks through its brittle texture that flakes easily under touch and pure white matte color, contrasting with sticky grime or yellowish patina, while on materials like ABS and polycarbonate it builds thickly and cracks during flexing, yet on nylon and polypropylene it develops sparse spots that roughen texture over time, so removal challenges include embedding into pores that worsens coverage with mechanical wiping or chemical dissolution damaging the base. Laser cleaning addresses these issues effectively, as pulses target the residue selectively and vaporize it without heat spread to the substrate, thus restoring surface uniformity already on delicate layers like acrylic or redwood.