Depending on the concentration and types of vapors migrating into a building, a vapor mitigation system may be necessary to protect the health of the occupants. There are two types of mitigation methods: Active or Passive. Passive methods include: sealing cracks, installing barriers, or below-grade venting. Active methods include: installing a sub-slab depressurization system, which mechanically vents vapors outdoors, and implementing structure over-pressurization, which involves adjusting building climate and ventilation to increase the indoor pressure relative to the sub-slab pressure.
VAPOR INTRUSION RESOURCES & INFORMATION
The Michigan Department of Environment, Great Lakes, and Energy (EGLE) and United States Environmental Protection Agency (EPA) have a multitude of PDFs and presentations regarding vapor intrusion: www.michigan.gov/deq/0,4561,7-135-3311_4109_66336---,00.html and https://www.epa.gov/vaporintrusion