Deodorization
Deodorization removes or neutralizes odor molecules; it is not masking. The exam tests source control, method selection, occupancy safety, and verification.
Core rules
- Remove the source first: contaminated insulation, char, debris, and residues. Cleaning is the primary deodorization step.
- Ventilate and filter: HEPA for particles, carbon for gases; use negative pressure to protect unaffected areas.
- Choose methods by situation: thermal fogging for confined, unoccupied spaces; ULV misting for surface treatment; ozone only in unoccupied spaces with warnings and ventilation; hydroxyl generators where occupancy rules allow; sealants only after cleaning.
- Follow label and safety requirements: ozone is a respiratory hazard; never use it with people or pets present; post warnings and ventilate before reoccupancy.
- Deodorize contents and HVAC, not just air.
- Verify with a structured odor check after the space is dry and cleaned.
Worked example
A bedroom smoke odor persists after walls are cleaned. The technician wants to ozone the occupied house. Reasoning: ozone cannot be used with occupants, and odor may be coming from carpet padding and bedding. The correct sequence is to remove contaminated padding, clean hard surfaces, launder or replace textiles, clean the HVAC path, and then, if needed, use an unoccupied-space method with posted warnings and reentry ventilation.
Traps that cost marks
Fogging over dirty surfaces; using ozone as a shortcut with occupants present; treating air while leaving contaminated contents; sealing before cleaning; skipping verification.