Smell Atlas
Follow the pathway, not only the label.
Onset, duration, airflow and nearby systems often separate moisture, drainage, combustion and electrical sources.
Describe your clue →Urine-like odor
Map the strongest low and high locations before assuming a single source.
- Trigger
- humidity and warming
- Strongest location
- floor edge, attic, crawl or fixture
Ammonia-like odor
Sharp alkaline odor often concentrates near contaminated porous material.
- Trigger
- warmth and humidity
- Strongest location
- attic, crawl or storage area
Sweet chemical odor
Do not use odor alone to identify the chemical; ventilate and inspect the likely source safely.
- Trigger
- equipment operation or spill
- Strongest location
- mechanical area or stored product
Sweet or fruity basement odor
Use timing and nearby products or equipment to narrow the category before entering confined areas.
- Trigger
- humidity or equipment cycle
- Strongest location
- basement storage or mechanical area
Chlorine-like odor
Ventilation and product handling context separate ordinary use from an abnormal release.
- Trigger
- cleaning or equipment cycle
- Strongest location
- bathroom, pool or mechanical area
Paint or solvent odor
Timing relative to application and ventilation is central.
- Trigger
- recent work or heat
- Strongest location
- painted room or storage
Smoke odor without visible smoke
Unexplained smoke odor requires immediate fire and combustion assessment.
- Trigger
- fire, appliance or backdraft
- Strongest location
- any occupied area
Earthy odor after rain
Fast onset after rain suggests a moisture or airflow pathway.
- Trigger
- rain
- Strongest location
- basement, crawl or wall opening
Moldy-clothes odor
Fabric can be the odor reservoir even when the room surface appears dry.
- Trigger
- storage and low drying
- Strongest location
- closet, laundry or wardrobe
Wet-wood odor
Woody odor strengthens before visible decay may be obvious.
- Trigger
- rain or plumbing wetting
- Strongest location
- framing, siding or subfloor
Sewage odor
Sharp wastewater odor follows a drainage or seal pathway.
- Trigger
- trap loss or drainage pressure
- Strongest location
- fixtures, drains and pipe penetrations
Hot-dust odor
Often brief at seasonal startup but should fade rather than intensify.
- Trigger
- first heating cycle
- Strongest location
- radiator, heater or duct
Fishy electrical odor
Fishy odor can precede visible electrical damage.
- Trigger
- circuit load
- Strongest location
- switchgear and devices
Ozone or metallic electrical odor
Metallic ozone-like odor with electrical symptoms is a stop condition.
- Trigger
- motor or electrical operation
- Strongest location
- panel, motor or electronics
Burning-plastic odor
Hot polymer odor with warmth, buzzing or smoke is a critical stop signal.
- Trigger
- equipment or circuit load
- Strongest location
- outlet, panel, motor or appliance
Fuel-oil odor
Persistent fuel odor requires source isolation and qualified response.
- Trigger
- appliance operation or storage leak
- Strongest location
- tank, line or burner
Fuel-gas odorant smell
Leave the area and use local emergency procedures rather than tracing the leak yourself.
- Trigger
- supply leak
- Strongest location
- gas appliance or service
Rotten-egg odor
Treat a possible fuel-gas odor as an immediate safety event.
- Trigger
- supply leak or water chemistry
- Strongest location
- utility or plumbing area
Musty odor when HVAC starts
The first minutes of airflow reveal where odor is stored or drawn from.
- Trigger
- fan startup
- Strongest location
- duct, coil, pan or connected space
Musty odor
Earthy stale odor that strengthens where materials remain damp.
- Trigger
- humid periods or low airflow
- Strongest location
- porous finishes, cavities or stored contents
Burnt-rubber odor
Stop affected equipment when odor is persistent or accompanied by heat or smoke.
- Trigger
- equipment load
- Strongest location
- fan, pump or appliance
Dead-animal odor
Strong decay odor rises, peaks and then changes over days.
- Trigger
- time after animal entry
- Strongest location
- wall, attic, crawl or duct void
Sewage odor during windy weather
Direction-specific occurrence points to pressure at the venting system.
- Trigger
- wind
- Strongest location
- roof vent, trap or pipe opening
Damp-earth odor
Soil-like odor often moves with air rather than appearing only at a wet surface.
- Trigger
- rain or pressure change
- Strongest location
- crawl space, basement or slab openings
Stagnant-water odor
Odor changes when water is flushed, drained or disturbed.
- Trigger
- low use or blocked drainage
- Strongest location
- traps, pans and hidden reservoirs
Describe first. Interpret second.
- TriggerWhat changed immediately before it began?
- CycleDoes it follow startup, flow, heating, wind or room use?
- LocationWhere is it strongest, and does that move?
- Stop conditionHeat, smoke, gas or electrical odor changes the response immediately.