| The U.S. Environmental Protection Agency (EPA) Principles for Greener Cleanups outline the Agency's policy for evaluating and minimizing the environmental footprint of activities involved in cleaning up contaminated sites. Use of the best management practices (BMPs) recommended in EPA's series of green remediation fact sheets can help project managers and other stakeholders apply the principles on a routine basis, while maintaining the cleanup objectives, ensuring protectiveness of a remedy, and improving its environmental outcome. Soil vapor extraction (SVE) is used at certain sites to address volatile organic compounds (VOCs) that are sorbed to soil within the unsaturated zone. An SVE system extracts air from, or sometimes injects air into, the vadose zone to strip the VOCs from soil and transfer the vapors to an aboveground treatment system for destruction or recovery. In contrast, air sparging (AS) involves injecting air into contaminated groundwater to drive volatile and semi-volatile contaminants into the overlying vadose zone by way of volatilization. The vapors are then removed from the vadose zone, typically by a co-located SVE system. Cleanup at some sites also may require mitigation of vapor intrusion (VI) into nearby buildings until remediation of soil or groundwater is complete. |