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​Vapor intrusion is the process by which chemicals in soil or groundwater can get into indoor air. Like radon gas, volatile organic compounds (VOCs) from vapor intrusion have become a significant environmental issue for regulators, business owners, and concerned residents.

Vapor intrusion is of particular concern to commercial properties, as past businesses in the area may have contributed to pollutants in the surrounding soil, exposing people in high-traffic areas to potentially harmful air quality. Sometimes chemicals are spilled on the ground at a factory, storage yard, or dry cleaner, or they leak from an underground storage tank.


A difference between interior and exterior pressures can cause soil vapor to enter a
building through cracks or perforations in slabs or basement floors and walls, and through openings around sump pumps or where pipes and electrical wires go through the


Strategies for mitigating vapor intrusion include both active and passive techniques, both of which require careful engineering design. A test can be performed to confirm potentially-harmful levels of vapors before mitigating. Mitigation may also be undertaken as a proactive measure to avoid a costly characterization study. 


Our vapor intrusion mitigation strategies include:

  • Sub-slab depressurization systems that either reverse
    the direction of air flow or dilute the contaminants
    with ambient air

  • Drain-tile depressurization

  • Block wall depressurization

  • Site remediation technologies such as soil vapor extraction

  • Indoor air purifiers or adsorption systems such as carbon filtration

  • Heat recovery ventilation technology

  • Passive sub-slab venting, a technology that relies on convective flow

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