The Scientific Advisory Group for Total Atmospheric Deposition (formerly the SAG on Precipitation Chemistry) has recently broadened its scope to include dry as well as total deposition, reflecting current scientific understanding that total atmospheric deposition—encompassing both wet and dry processes—more fully represents the exchange between the atmosphere and the Earth’s surface, whereas precipitation chemistry and wet deposition alone capture only part of this interaction. The group aims to enhance the comprehensive understanding and quantification of total atmospheric deposition, which is essential for meeting the needs of the GAW Programme.