Begin with the decision the assessment must support
“Is the air okay?” is understandable, but it is too broad to define a useful test. Explain the fire exposure, affected materials, completed cleaning, remaining concerns and who will use the space. Ask a qualified assessor what question can be answered, what cannot be concluded and how the result would change the work or use of the property.
Assessment can involve the building and contents as well as the air. If an affected material remains in a cavity or a system has not been examined, a narrow test may leave that issue unresolved.
Know what different observations tell you
| Observation | Useful information | Limit |
|---|---|---|
| Visible residue | A location and material needing assessment. | Does not identify every contaminant or the full boundary. |
| Odour | A reason to investigate a source and treatment outcome. | Does not measure every exposure or establish safe use. |
| Particle reading | Particle levels under the instrument’s method and conditions. | Does not describe all gases, residues or material hazards. |
| Targeted sample | Information about a defined analyte, location and time. | Does not automatically represent every room or future condition. |
Ask the assessor to explain any comparison criteria, sampling limitations and conditions during the test. Keep the full report rather than only a “pass” screenshot.
Air cleaning and source removal do different jobs
Particle filtration can be part of managing smoke, but it does not remove an affected building material. Health Canada’s cleaner-air guidance discusses filtration and reducing indoor particle sources during wildfire events. That guidance is not a substitute for assessing a fire-damaged structure or its systems.
Source: Health Canada · cleaner air during wildfire smoke.
For a portable cleaner, follow the manufacturer’s room-size and filter instructions. Ask an HVAC professional before changing the system beyond its capability or restarting equipment affected by fire, water or residues. Keep system assessment in the restoration scope.
Source: IICRC · S590 HVAC assessment scope.
Do not use ozone around occupants
EPA states that ozone can harm the lungs and explains why ozone-generating air cleaners can be ineffective or difficult to control. Do not interpret a fresh smell, product badge or marketing claim as proof of a safe indoor environment. Any proposed specialist odour treatment needs a clear work plan and re-entry process.
Prepare an assessment brief
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For symptoms or personal health questions, contact a qualified health professional. For the cleanup contract, use the smoke and soot scope guide.
Sources and further reading
- Health Canada · cleaner air during wildfire smoke
- IICRC · S590 HVAC assessment scope
- US EPA · ozone generators and indoor air
Reviewed October 11, 2026. Follow the source’s current guidance and the instructions for the actual property.