The ISO 5630-6:2009 standard specifies a test method for accelerated paper and Cardboard aging by exposure to nitrogen dioxide gas to assess their mechanical and Optical Property changes under atmospheric pollution conditions. The method is suitable for all cellulose-based printing and writing papers, including Spreader and UnSpreader. By simulating the natural aging process of long-term exposure to polluted air, the standard predicts the durability and Stability of paper, providing a scientific basis for applications such as archival storage, printing encasement, etc.