Air Sparging is an in-situ remediation technique which is also known as "in-situ air stripping" and "in-situ volatilisation." It is used for reducing contaminants consisting of volatile constituents in petroleum products adsorbed to soils and dissolved in groundwater.

Air sparging  involves the injection of pressurised clean air or other suitable gases into the subsurface saturated zone.  This addition of air or gas causes by contact and mixing a phase transfer of hydrocarbons from a dissolved state to a vapour phase. Subsequently the air is retrieved through the use of extraction wells for treatment.

This technique is commonly used together with soil vapour extraction (SVE), but it can also be used with other remedial technologies. It has advantages in that it does not require the groundwater to be treated above ground.  In addition, the increased oxygen content of the subsurface can promote microbial degradation processes.

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When air sparging (AS) is combined with SVE, commonly referred to as AS/SVE, the SVE system causes a negative pressure in the unsaturated zone through a series of extraction wells in order to control any migration of the vapour plume.