The ISO 29664-2010 standard specifies a manual test method for simulating the weathering effect of plastics in heavily polluted outdoor environments. This standard pays particular attention to the effect of acid deposition on photochemical aging of plastics, as acid precipitation significantly accelerates the degradation process of polymers. The standard describes two exposure methods: Method A is suitable for products with significant surface degradation, using a short-term strong acid spray; Method B is suitable for products with deep penetration, using a weaker acid spray for a long-term treatment. Through these methods, the laboratory can control the efflorescence parameters and avoid fluctuations caused by acidic precipitation in the natural environment to more accurately assess the aging effect of plastics.