Trusting your eyes is risky. The particles that do the most harm are often invisible: PM2.5, PM1 and respirable crystalline silica penetrate deep into the lungs and stay airborne for hours. A space that looks clear after cutting or sanding can still exceed HSE Workplace Exposure Limits.

What “invisible” really means

• PM10 is the upper range you might just see in a beam of light; PM2.5 and PM1 are far smaller and remain suspended.
• RCS particles are respirable and hazardous at very low concentrations (UK WEL for RCS is 0.1 mg/m³).
• Settle time is deceptive. Footfall and airflow re-agitate fine dust from surfaces.

Controls that work when sight fails

Capture at source

• Use LEV or tool-mounted extraction matched to the tool. Keep hoses short, connections tight and filters maintained to preserve airflow under load.
• Consider water suppression to reduce generation where suitable.

Control the room

• Use air scrubbers or negative air machines with HEPA (H14 for fine or carcinogenic dusts). Place units to create a directional pull away from clean areas.
• Provide make-up air via a single controlled opening to stabilise flow.

Housekeeping without re-suspension

• Vacuum with M-Class or H-Class filtration. Avoid sweeping and compressed air.
• Seal and dispose of waste promptly to prevent secondary release.

Prove it with data

• Use a particulate monitor to track PM through the task and during clean-up.
• Record readings and control checks to support COSHH assessments.

Because the worst dust is often unseen, effective dust management relies on engineered controls and monitoring, not a visual check. Design the controls, then verify their performance.