Moisture changes how dust sticks to tools, floors, and filters. A thin water layer forms microscopic bridges between particles and surfaces, increasing adhesion. Hygroscopic dusts absorb water, grow in size, and deform into films that smear under traffic. Understanding this physics helps you choose controls that actually work on site.

The mechanics in brief

At moderate RH, capillary forces form where water wets contact points, effectively gluing dust to surfaces. As RH rises, particles agglomerate; as it falls, those clusters can break and become airborne again. Moisture also reduces static charge, so electrostatic attraction drops while capillary sticking rises.

Practical implications for extraction

Sticky, larger particles are harder to lift with marginal airflow. Keep capture at source close and well-sealed, reduce tool speed to limit fine aerosol, and maintain airflow under load by staging pre-filters. If humidity is the driver, use dehumidifiers to keep RH in a stable band so extraction efficiency remains consistent.

Surface cleaning and preparation

On floors, damp films spread dust rather than remove it. Vacuum before any damp mopping; never sweep or blow with compressed air. For coatings or resins, control RH to prevent amine blush and dust entrapment, and vacuum between prep stages with M or H Class filtration.

Filter and waste handling

Expect quicker filter loading when dust is tacky. Change pre-filters proactively, check gaskets for damp-related leaks, and bag moist waste immediately to stop it drying into a respirable source. Where respirable crystalline silica is present, align with HSE WELs and verify outcomes with a PM meter if available.

• Keep RH stable to limit capillary “glue” effects
• Shorten capture distances; protect airflow with staged filtration
• Vacuum first, then damp clean; avoid sweeping and compressed air
• Manage filters and waste before dried residues become airborne

Moisture does not just make dust heavier; it changes how it adheres. Control humidity, adapt extraction, and clean in the right order to keep adhesion working for you, not against you.