Opening windows and propping doors can feel like a quick win, but natural ventilation is unpredictable and rarely sufficient for construction dust. Wind direction, temperature and building layout create dead zones where respirable dust lingers. For substances like respirable crystalline silica (RCS), the HSE Workplace Exposure Limit is 0.1 mg/m³, a level you will not reliably maintain with weather-dependent airflow.

Why natural airflow falls short

• It is variable. A breeze can reverse or stall, leaving airborne particulate suspended.
• It is uneven. Corners, stair cores and voids can trap PM10 to PM1, well beyond the reach of a through-draught.
• It spreads contamination. Cross-venting can push dust to clean areas instead of controlling it.

What to use instead

Capture at source

• Fit tool-mounted extraction with M-Class or H-Class vacuums and keep airflow under load by maintaining filters and seals.
• Use water suppression where appropriate, and reduce cutting speed to limit dust generation.

Control the air

• Deploy air scrubbers or negative air machines with HEPA filtration (H14 for fine or carcinogenic dusts). Position units to pull air from the dirty zone towards discharge, avoiding short-circuits.
• Provide make-up air deliberately through a single controlled opening to stabilise flow.

Housekeeping that prevents re-agitation

• Avoid sweeping and compressed air. Use industrial vacuums with high-efficiency filtration and regular filter checks.
• Bag and seal waste promptly; damp-wipe ledges where dust settles.

Verify, do not guess

• Use a particulate monitor or air quality meter to check PM levels before, during and after works.
• Smoke pens or tracer puffs help visualise airflow paths and reveal dead spots.
• Record simple checks under COSHH: location, controls in use, readings, maintenance actions.

Natural ventilation can supplement a plan, but it should never be the plan. Combine source capture, controlled air filtration and disciplined housekeeping, and prove effectiveness with measurement rather than relying on a breeze.