Weird Smell Help
Hoping reddit can help explain our issue. Any thoughts are appreciated.
We live in a 4 year, newer built home. We have lived in it for 1.5 years now. We don't have any symptoms. We've noticed that the indoor staircase that leads from first floor to second floor always has this earthy/dirt/woody type smell that lingers despite using an air purifier. The smell only exists in the stairway and has been there since we moved in. We finally got around to having a mold inspector come out to examine. None of our walls or floors have retained moisture or signs of mold.
He also ran an indoor air quality test. My concern is the high TVOC and HCHO findings. Below are the results:
The following results were pulled directly from the meter readings and are presented as combined screening averages where available. Measurements were taken in the stairwell near two large uncovered windows. Recorded ambient conditions were 75.6°F and 58.7% relative humidity.
The home is approximately four years old, with wood flooring installed in some areas approximately one year ago (not near staircase). No recent household chemical use, painting, refinishing, new furniture, mattresses, or spray foam installation was reported.
Screening results and recommended levels
| Parameter | Screening result | Guideline or reference | Interpretation |
|---|---|---|---|
| Total volatile organic compounds—TVOC | 1.416 mg/m³, combined average | No universal health-based TVOC limit. German indoor-air guidance recommends avoiding concentrations above 0.950 mg/m³ as a precaution. | Above this precautionary reference numerically. Laboratory testing is needed because screening and laboratory methods are not directly equivalent. |
| Formaldehyde—HCHO | 0.189 mg/m³, combined average | WHO guideline: 0.100 mg/m³ over 30 minutes. | Approximately 1.9 times the guideline concentration. Confirmatory sampling is recommended; these readings do not establish a validated 30-minute exceedance. |
| Fine particles—PM2.5 | 1 µg/m³, combined average | WHO guideline: 15 µg/m³ over 24 hours. | Low during screening. A short reading does not establish the daily average. |
| PM10 | 1 µg/m³ | WHO guideline: 45 µg/m³ over 24 hours. | Low during screening; not a daily exposure measurement. |
| PM1.0 | 0 µg/m³ displayed | No separate WHO numerical guideline. | No response above the displayed resolution; this does not establish complete absence. |
| Carbon dioxide—CO₂ | 720 ppm | No universal residential pass/fail value. | Does not independently establish adequate ventilation or control of VOCs. |
| PM2.5 air quality index | 4 | Displayed particle-related index; calculation method not verified. | Consistent with the low particle reading. Does not describe VOC or formaldehyde conditions. |
| Relative humidity | 58.7% | EPA recommends below 60%, ideally 30–50%. | Below the recommended upper level but above the preferred range. |
| Ambient temperature | 75.6°F | No single temperature establishes acceptable indoor air quality. | Evaluate alongside humidity, comfort, and sunlit surface temperatures. |
TVOC, HCHO, and PM2.5 are combined averages. Other values are individual recorded readings or field conditions.