Air Force Ones can turn yellow over time due to several factors: Oxidation: The materials used in the construction of the sneakers, particularly the rubber soles and the synthetic or leather upper, are susceptible to oxidation. Exposure to oxygen in the air causes a chemical reaction that leads to the yellowing of these materials. This process is accelerated when the shoes are stored in areas with high humidity or temperature. Ultraviolet (UV) exposure: Sunlight and other sources of UV light can cause the materials in the sneakers to break down over time, leading to discoloration. UV exposure can affect the color of the synthetic or leather upper, as well as the rubber soles. Prolonged exposure to sunlight speeds up this process, causing the sneakers to yellow more quickly. Sweat and moisture: Wearing the sneakers for extended periods can cause sweat and moisture to be absorbed by the materials, particularly the insoles and lining. This can lead to a buildup of bacteria and other microorganisms, which can contribute to discoloration. Dirt and grime: Accumulation of dirt and grime on the shoes can cause them to turn yellow. This is particularly true for lighter-colored sneakers, where stains and discoloration are more noticeable. Aging: Over time, the materials used in the sneakers can break down and lose their original color. This is a natural process that occurs as the sneakers age, and is more noticeable in lighter-colored sneakers. To prevent or slow down the yellowing process, it's essential to take proper care of your Air Force Ones. This includes cleaning them regularly, avoiding prolonged exposure to sunlight, storing them in a cool and dry place, and using sneaker protection products to minimize the effects of oxidation and UV exposure.