GB/T 40512-2021 applies to components and assemblies on complete vehicles, specifying the atmospheric exposure test methods in natural environments. The standard defines the test conditions, procedures, data processing, and result evaluation requirements. The core approach involves using equipment such as solar radiometers, black standard temperature sensors, and data recording instruments, combined with automatic solar tracking devices, to conduct tests at exposure sites in representative climatic regions. By continuously monitoring environmental parameters such as solar radiation, temperature, humidity, and air pressure over the long term, and periodically inspecting the appearance, performance, and corrosion of components, the standard evaluates the ability of vehicles to withstand atmospheric aging and corrosion.