Dust Complaint Investigation

What the dust pattern can show

The position, colour, texture and recurrence of deposits help shape the investigation. Dust concentrated below supply grilles raises different questions from debris beside a construction partition. A uniform fine layer across an office may relate to cleaning frequency, normal indoor sources or outdoor ingress, whereas dark streaks around a diffuser can reflect surface marking as air moves across a ceiling. These observations guide testing but do not identify composition by appearance alone.

Sources considered in commercial buildings

We review construction or refurbishment, including access routes, hoardings and controls used by the works contractor. The HVAC review covers filter condition, fit and bypass, accessible air-handling components, grilles and duct cleanliness where relevant. Indoor sources include paper, textiles, ceiling materials and process activities. External ingress is considered alongside doors, loading areas and air intakes. Cleaning methods are reviewed because they can remove or redistribute deposits.

A staged investigation method

The survey starts with a complaint map and photographs showing where dust settles and how quickly it returns. We compare affected surfaces with suitable control areas, review works and maintenance records, and inspect likely pathways. Real-time particulate logging can compare airborne particle patterns during occupied periods, cleaning, deliveries or construction activity. Surface samples may be collected for microscopy or other characterisation when composition could distinguish sources. If ductwork is suspected, filter and accessible duct inspections can be followed by deposit thickness testing at representative locations.

1. 1

   Map the deposits

   Record affected rooms, surfaces, recurrence, cleaning dates and nearby activities.

2. 2

   Inspect source routes

   Review works boundaries, doors, ceiling voids, filtration, grilles and accessible ductwork.

3. 3

   Monitor airborne patterns

   Log particles at complaint and comparison points during relevant operating periods.

4. 4

   Characterise material

   Use surface sampling where particle type can help separate credible sources.

5. 5

   Test duct deposits if justified

   Apply DTT at suitable representative points when ductwork is a supported hypothesis.

Sampling locations, duration and context

Monitoring positions are selected to compare the complaint area with a less-affected space and, where useful, an outdoor or boundary location. The period is agreed around the suspected event: occupied use, cleaning, delivery activity, ventilation start-up or nearby works. Real-time logging shows changes over time but does not identify particle composition. Surface characterisation describes collected material but may include a mixture accumulated over days. DTT quantifies deposits at tested duct locations; it does not by itself prove that those deposits caused dust on desks.

From findings to corrective work

The report separates source evidence from contributing conditions. Actions might include correcting filter fit, sealing a migration route, improving works containment, changing cleaning equipment, protecting an intake, or commissioning further inspection of inaccessible duct sections. Mechanical defects are referred to the HVAC contractor, construction controls to the principal contractor, and cleaning measures to the responsible facilities provider. Where several sources remain possible, the report proposes a controlled change or follow-up comparison to test the leading explanation.

Is this the right page?

Choose Duct Cleanliness Testing for a planned assessment of internal duct condition. Office Dust Deposits explains recurring deposits as a building-management issue, while Construction Impact on Buildings focuses on emissions from nearby works.