Vapor Intrusion Mitigation Services

Safeguarding Indoor Air Quality, Achieving Regulatory Compliance, Protecting Property Value

Trinity Source Group delivers comprehensive vapor-intrusion assessment and mitigation for commercial and residential properties. We evaluate site conditions, design effective controls, and guide projects through California’s evolving local and state regulatory frameworks.

CORE CAPABILITIES

Service Area

Key Activities

Regulatory Coordination

  • Liaise with County Environmental Health Departments, the Department of Toxic Substances Control (DTSC), and Regional Water Quality Control Boards (RWQCBs).

  • Prepare permit applications, technical memoranda, and responses to agency comments.

  • Track compliance milestones to prevent schedule and cost overruns.

Risk Assessment

  • Develop conceptual site models using soil-gas sampling, indoor-air monitoring, and subsurface characterization.

  • Quantify exposure pathways and establish mitigation performance criteria.

Mitigation Design

  • Specify active or passive vapor-intrusion mitigation systems (VIMS) and sub-slab depressurization systems (SSDS) matched to site-specific risks.

  • Coordinate with project architects and contractors to avoid conflicts with foundations, utilities, and other building systems.

  • Incorporate flexibility to toggle between passive and active modes based on monitoring results.

Construction Quality Assurance (CQA)

  • Perform field inspections to confirm correct installation of vapor barriers, piping, fans, and mechanical components.

  • Conduct sub-slab pressure testing, soil-gas sampling, and indoor-air verification prior to occupancy.

Operations, Monitoring & Maintenance (OM&M)

  • Prepare OM&M plans that define inspection frequency, sampling requirements, and performance metrics.

  • Analyze monitoring data and recommend system optimization or mode changes.

System Decommissioning

  • Document risk reduction and negotiate “No Further Action” determinations when vapor concentrations remain below regulatory action levels.

  • Provide closure reports and certify safe conditions for continued site use or redevelopment.

APPROACH HIGHLIGHTS

  • Data-Driven Decisions

    Designs are based on quantified risk thresholds, not generic assumptions.

  • Local Expertise

    Extensive experience with Central Coast geology and California regulatory expectations.

  • Transparent Communication

    Clear, timely reporting keeps clients and regulators aligned throughout the project lifecycle.

Contact Trinity Source Group to discuss assessment needs, design requirements, or long-term stewardship for your vapor-intrusion project.