Indoor air investigations

Indoor air investigations for UK commercial buildings

When occupants report complaints or a building is suspected of underperforming, a structured investigation isolates the environmental factors at play — combining continuous sensors, lab-grade sampling and ventilation review into a single defensible report.

CO₂612 ppmPM2.58 µg/m³VOC0.21 mg/m³RH46 %

What we investigate

The four investigation pillars

Most building-related complaints are explained by a small set of measurable factors. Investigation is the disciplined process of ruling each in or out with calibrated data rather than assumption.

Ventilation

CO₂ / Δp

Outdoor air supply vs occupancy load.

Chemistry

TVOC / HCHO

Material emissions and cleaning chemistry.

Particles

PM2.5 / PM10

Outdoor ingress and indoor sources.

Comfort

T / RH

Thermal envelope and humidity control.

Complaint mapping

Occupant reports plotted against zone, shift and HVAC mode to focus the sensor plan.

Continuous monitoring

Multi-zone sensors capture diurnal patterns the eye and nose miss.

Targeted sampling

Sorbent tubes, DNPH cartridges and viable mould samples for laboratory analysis.

Findings report

Plain-English conclusions, prioritised actions and benchmark comparison.

When to investigate

Triggers for a formal indoor air investigation

Persistent occupant complaints, post-refurbishment concerns, suspected ventilation underperformance, or due-diligence requirements ahead of a lease event. Investigations are also used to verify remedial works after HVAC, fabric or cleaning regime changes.

Pair an investigation with indoor air quality monitoring, indoor air quality testing and indoor environmental monitoring for a complete picture.

Benchmarks

Reference frameworks used in investigations

ReferenceScopeUse
WHO IAQ Guidelines (2010 / 2021)Pollutant exposure limitsHealth benchmarking
BS EN 16798-1Indoor environmental categoriesBuilding classification
CIBSE TM40 / Guide AVentilation and comfortDesign vs measured gap
WELL v2 / RESET AirContinuous monitoringOccupant-facing targets
HSE INDG244Workplace temperatureStatutory comfort guidance

Commission an indoor air investigation

Structured monitoring, sampling and reporting that answers the question on the table.

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