Introduction In-situ air sparging (IAS) is a remediation technique that uses air to remove volatile and degradable contaminants from soil and groundwater. Air is injected below the water table, and then travels upward toward the surface due to buoyant pressures. Volatile contaminants are removed as they partition into the flowing air. Air also dissolves into the groundwater, which increases the oxygen content thereby stimulating aerobic biodegradation. The injected air generally forms a plume that passes through the soil in a series of channels.