Volatile organic compounds (VOCs) in the shallowest groundwater (the water table) can evaporate and move through the soil as a gas. Under certain conditions, these vapors can make their way indoors, affecting air quality in buildings above the ground.
Groundwater impacted by volatile organic compounds (VOCs) like trichloroethene (TCE) and vinyl chloride can release small amounts of vapor into the soil. These vapors rise toward the surface of the ground through gaps between soil particles. These VOCs are chemicals found in many common household products like stain removers, upholstered furniture, and cigarette smoke.
Although VOCs are common and in the air of just about every indoor setting, ensuring that contamination doesn’t add to what may already be present is an important part of cleanup and keeping people safe.
Specific conditions required
Under certain conditions, soil vapors that reach building foundations can move inside the building. They can build up in the air in enclosed areas, such as crawl spaces. Whether the vapors enter the building and how much they might impact indoor air quality depends on many factors. These factors include:
- The building’s ventilation
- How concentrated the groundwater contamination is
- Soil conditions above the water table
- The type of foundation a building has — slab, crawl space, or basement
- The integrity of a building’s foundation