Aging impact on silver-functionalized silica aerogel (Ag⁰-aerogel) in the off-gas streams including dry air, humid air, 1% NO/N₂, and 2% NO₂/dry air were studied. Aged Ag⁰-aerogel was prepared through a continuous-flow aging system by exposing Ag⁰-aerogel (unaged) to the off-gas streams at different aging temperatures and time. Iodine loading capacity on the aged Ag⁰-aerogel was obtained through a continuous-flow adsorption system. Iodine loading capacity losses were observed after the Ag⁰-aerogel was exposed to the off-gas streams. Characterization studies were conducted to observe the physical and chemical changes of the Ag⁰-aerogel after exposed to gas streams. According to iodine adsorption data and analyses, it was revealed that iodine loading capacity on the aged Ag⁰-aerogel in the off-gas streams decreases with increasing aging temperatures and time. The pseudo reaction model describes experimental data well and the oxidation of Ag⁰ is the rate determining step in the aging process.