Thoracic dust is defined by the World Health Organization as the fraction of airborne particles small enough to pass through the head airways and reach the conducting airways of the lungs. This fraction—often associated with PM₁₀—has a mass median aerodynamic diameter of about 10 µm. It sits between inhalable and respirable dust, and its accurate measurement is essential when evaluating exposures to substances that deposit in this region of the respiratory tract.
Regulatory Context in Canada
In Ontario, occupational exposure limits for thoracic dust apply specifically to cotton dust, cobalt, and sulfuric acid. Monitoring these substances helps employers meet provincial requirements and document exposure control efforts. For consultants, thoracic dust sampling provides the data needed to evaluate compliance and support recommendations for engineering controls or process adjustments.
Why Thoracic Dust Measurement Is Important
Industries that generate fine particulate matter—manufacturing, chemical processing, textiles, and others—may expose workers to particles that deposit deep in the airways but not as deeply as respirable dust. This intermediate fraction can contribute to chronic respiratory irritation, inflammation, and long‑term health effects. Reliable sampling and analysis help determine whether exposures are within acceptable limits and whether additional controls are needed.
Sampling Equipment and Methodology
Thoracic dust is collected using size‑selective cyclones designed to capture the PM₁₀ fraction. LCS Laboratory supplies:
- thoracic cyclones
- calibrated personal sampling pumps
- cassettes suitable for thoracic dust collection
These tools support consistent sampling aligned with Canadian regulatory expectations. Consultants can adjust sampling duration to match the work shift or specific exposure scenario.
Laboratory Analysis
LCS Laboratory Inc. is currently the only commercial laboratory in North America providing size‑selective sampling for thoracic dust. Samples are returned to LCS Laboratory for analysis under NIOSH 5524 or MDHS 14/4, depending on the project requirements. These methods allow precise quantification of thoracic particulate mass and, when needed, analysis of specific contaminants such as cobalt or sulfuric acid mist. The resulting data can be used directly in exposure assessments, compliance reports, and control evaluations.
Working With a Canadian Laboratory
For Canadian clients, using a national laboratory simplifies logistics and avoids currency‑related cost fluctuations. Turnaround times are predictable, and shipping is straightforward across all provinces. Consultants also have access to technical support for equipment setup, sampling plans, and interpretation of analytical results. If you have any questions, or would like to request a quote, please email us via our contact form. ©
