COSHH Air Monitoring

What is COSHH air monitoring?

Hazardous substances monitoring measures the airborne concentration of any airborne substance hazardous to health covered by your COSHH assessment 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 COSHH air monitoring across manufacturing, construction, engineering, pharmaceutical, chemical 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 COSHH air 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. Hazardous substances monitoring provides the objective evidence that satisfies this duty.

Uncontrolled exposure to hazardous substances is linked to the full range of COSHH-related occupational illnesses. 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 COSHH air monitoring

We measure exposure using personal air sampling tailored to each hazardous substance in your COSHH assessment, following the recognised COSHH Reg 10 / 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

Hazardous substances 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 COSHH air monitoring process

Our COSHH air 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 COSHH air 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

When does COSHH require air monitoring?

When monitoring is needed to protect health, when a workplace exposure limit could be exceeded, when control failure could cause serious harm, or to verify that controls remain effective.

How does monitoring fit with our COSHH assessment?

Air monitoring validates the assumptions in your COSHH risk assessment with real measured data and informs whether controls need improving.

How long must we keep the records?

Personal exposure monitoring records must generally be kept for at least 40 years where health records are involved, and five years otherwise; we provide reports formatted for retention.