Welding fume does not stay afloat for long. Fine metal-oxide particles rise in the thermal plume, collide, and agglomerate into heavier clusters that drop onto benches, tools, and floors. This surface contamination matters: it re-aerosolises with footfall and air movement, undermining controls and housekeeping.

Why deposits build quickly

• Thermal buoyancy then cooling: hot fume rises, cools above head height, slows, and falls into eddies around fixtures.
• Agglomeration: particles collide and stick, increasing effective size and settling speed.
• Humidity and oil films: residues adhere to slightly damp or oily surfaces, especially near cutting fluids.
• Airflow shortcuts: cross-draughts push fume out of capture zones and into “dead spots” where it drops.

Practical controls that work

• Capture at source: keep torch-mounted or hood LEV within the recommended distance and angle to the arc. Avoid high cross-draughts that break the capture zone.
• Direct the room airflow: use air scrubbers or negative air machines to pull from the weld zone towards filtration, not across the operator. Prioritise airflow under load, not free-air figures.
• Position intakes high for rising plume, with returns arranged to prevent recirculating pockets over benches.
• Housekeeping without re-aerosolising: vacuum, never sweep or blow. Pair an industrial unit and high-efficiency filtration; many shops use Supra vacuums for routine fume residue removal.
• Filter strategy: for fine or carcinogenic particulates, use HEPA to H14 in air scrubbers and industrial vacuums as required.
• Routine wipe-down: where safe, damp-wipe high-touch surfaces after vacuuming to lock in fines.
• Verify: spot-check with a particulate monitor during and after work to see where deposits reform.

Applying the three-layer approach

• Capture at source: torch extraction or well-placed hoods.
• Capture in the air: air scrubbers or LEV with adequate m³/h and maintained filters.
• Capture on surfaces: H-class industrial vacuuming and scheduled cleaning.

Under COSHH, HSE expects effective LEV and suitable housekeeping for welding fume. Treat surface dust as a respiratory risk: control creation, control dispersion, then remove safely. The pay-off is cleaner air, fewer rework interruptions, and more reliable compliance.