Exposure assessment

Indoor air exposure & environmental risk assessment

An exposure assessment quantifies what occupants are actually breathing over a working day — and benchmarks it against WHO, WELL and BS EN 16798 references. It is the basis for defensible decisions on ventilation, materials and cleaning regimes.

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

Assessment scope

What is quantified

An exposure assessment moves beyond a snapshot. We capture time-weighted averages, peak excursions and the proportion of occupied time spent above each reference.

TWA

8-hour mean

Time-weighted average over the working day.

Peaks

15-min max

Short-term excursions linked to activity.

% over

Exceedance time

Share of occupied hours above target.

Pattern

Diurnal

How exposure varies through the day and week.

Multi-parameter monitoring

CO₂, PM2.5, PM10, TVOC, HCHO, T and RH captured continuously across representative zones.

Laboratory analysis

Speciated VOCs by TD-GC-MS and formaldehyde by DNPH/HPLC for defensible numbers.

Risk framing

Findings framed against WHO, WELL, BS EN 16798 and HSE references — without overstating health implications.

Documented report

Concise written report suitable for facilities, HR, design teams and lease-event due diligence.

When to use

Where exposure assessment is the right tool

Pre- and post-refurbishment verification, lease-event due diligence, response to occupant complaints, WELL and BREEAM submissions, and any situation where a written, defensible characterisation of indoor exposure is required.

Combine with indoor air investigations, indoor environmental monitoring and indoor air pollution testing.

Benchmarks

Reference frameworks applied

ReferenceApplicationOutput
WHO IAQ Guidelines (2010 / 2021)Health-based exposure limitsTWA comparison
BS EN 16798-1Indoor environmental categoriesCategory I–IV rating
WELL v2 AirOccupant-facing targetsPerformance verification
BREEAM Hea 02Pre-handover IAQCompliance evidence
HSE INDG244 / Workplace RegsTemperature & basic comfortStatutory check

Commission an exposure assessment

Quantify occupant exposure, benchmark against recognised references and act on the findings.

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