This standard provides three exposure test methods for the climatic aging of plastics using sunlight, including direct exposure, sunlight exposure after glass filtration, and intensified sunlight exposure using Fresnel mirrors. These methods evaluate the performance changes of plastics under the combined effects of solar radiation, temperature, humidity, and other factors through prolonged exposure under specific outdoor conditions. The core instruments for conducting such tests are standardized outdoor natural climate aging exposure racks and accelerated aging test chambers equipped with Fresnel mirror arrays (such as optical accelerated aging devices compliant with standards like ASTM G90), which simulate and intensify the effects of sunlight. The test cycles are typically long (e.g., 12 months or more), serving as an important basis for evaluating the weather resistance and lifespan prediction of plastics.