Respirable Dust Monitoring

What is respirable dust monitoring?

Respirable dust monitoring measures the airborne concentration of the fine fraction of airborne dust able to penetrate to the gas-exchange region of the lung 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 respirable dust monitoring across manufacturing, construction, minerals processing, woodworking, foundries 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 respirable dust 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. Respirable dust monitoring provides the objective evidence that satisfies this duty.

Uncontrolled exposure to respirable dust is linked to chronic lung disease, reduced respiratory function and pneumoconiosis. 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 respirable dust monitoring

We measure exposure using a respirable cyclone and pre-weighed filter on a calibrated personal pump, analysed gravimetrically, following the recognised MDHS 14/4 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

The current workplace exposure limit for respirable dust is 4 mg/m3 (8-hour TWA) (EH40/2005, as amended). 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 respirable dust monitoring process

Our respirable dust 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 respirable dust 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 counts as respirable dust?

It is the fine size fraction (around 4 microns median) that penetrates to the alveolar region of the lung, separated from larger particles by a cyclone sampler.

What is the respirable dust limit?

The general workplace exposure limit is 4 mg/m3 as an 8-hour TWA, though substance-specific limits (such as silica) take precedence where they apply.

How is it analysed?

By gravimetric analysis — the filter is weighed before and after sampling under controlled conditions to determine the collected mass.