Workplace Exposure Monitoring

What is workplace exposure monitoring?

Occupational exposure monitoring measures the airborne concentration of hazardous substances such as dusts, fumes, solvents and gases encountered during work that workers may breathe in during normal operations. It quantifies real personal exposure so employers can judge whether existing controls are adequate.

IndustrialAirMonitoring.uk provides independent workplace exposure monitoring across manufacturing, construction, pharmaceutical, chemical, engineering sites throughout the UK. Our occupational hygienists deliver defensible exposure data that demonstrates compliance with the Control of Substances Hazardous to Health Regulations 2002 (COSHH) and the workplace exposure limits set out in HSE guidance note EH40.

Why workplace exposure monitoring matters

Under COSHH Regulation 10, employers must monitor exposure to hazardous substances where it is needed to protect health, where a workplace exposure limit could be exceeded, or where control measures need to be verified. Occupational exposure monitoring provides the objective evidence that satisfies this duty.

Uncontrolled exposure to occupational exposure is linked to occupational lung disease, dermatitis, asthma and systemic toxic effects. Beyond the legal duty, robust monitoring protects your workforce, reduces the risk of enforcement action and civil claims, and gives insurers and clients confidence that exposure is being actively managed.

How we carry out workplace exposure monitoring

We measure exposure using breathing-zone personal air sampling using calibrated pumps and the appropriate sampling media, following the recognised BS EN 689 / MDHS methodology. Personal samplers are worn in the breathing zone for a representative full shift to derive an 8-hour time-weighted average, while static (background) samples help map contaminant sources across the workplace.

Samples are analysed by an accredited laboratory and the results compared with the relevant occupational exposure limit. Where short-term peaks are a concern we add 15-minute short-term exposure limit (STEL) sampling, so both the chronic and acute risk picture is captured.

Standards, limits and reporting

Occupational exposure is controlled to as low as is reasonably practicable, with sampling benchmarked against published occupational and in-house standards. We assess compliance using the BS EN 689 statistical decision framework, which accounts for exposure variability rather than relying on a single result.

Your report sets out the measured concentrations, the compliance position, the adequacy of existing controls such as local exhaust ventilation, and a recommended re-monitoring interval. It is written to be understood by managers and to satisfy HSE inspectors, auditors and insurers.

Our workplace exposure monitoring process

Our workplace exposure monitoring programmes follow a structured, four-stage workflow so the results stand up to scrutiny. Request monitoring or book a site assessment to begin.

1Scoping & site survey. We review your processes, COSHH assessments and previous workplace exposure monitoring data, then plan a representative sampling strategy using BS EN 689 similar exposure groups.
2On-site sampling. Qualified occupational hygienists carry out calibrated breathing-zone and static measurements across a representative shift, with full chain-of-custody documentation.
3Accredited analysis. Samples are analysed using the relevant MDHS / ISO laboratory method and the results are compared against the applicable workplace exposure limit.
4Reporting & recommendations. You receive a clear exposure report with compliance status, control recommendations and a re-monitoring interval — defensible evidence for HSE, insurers and auditors.

Frequently asked questions

What is occupational exposure monitoring?

It is the measurement of how much of a hazardous substance an individual worker is exposed to during their work, expressed as a time-weighted average and compared with the workplace exposure limit.

Who needs workplace exposure monitoring?

Any employer whose processes release hazardous substances into the air — and especially where a substance has an assigned workplace exposure limit or causes serious health effects.

How do you decide who to sample?

We group workers into similar exposure groups under BS EN 689 and sample a representative selection, so the results describe the whole group reliably.