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Mold spore penetration through wall service outlets: a pilot study
Brad Muise1, Dong-Chul Seo, E Earl Blair
1Department of Applied Health Science, Indiana University, Bloomington, IN, 47405, USA. bmuise@indiana.edu
Abstract:
A pilot study was conducted to estimate fungal spore penetration for wall service outlets subjected to a constant air pressure. During the laboratory experiment, a wall chamber was fabricated, and telephone, electrical, and cable service outlets were installed. Penicillium chrysogenum spores were aerosolized into the chamber that was held under pressure. Spores that penetrated the outlets were funneled into an impinger for microscopic enumeration. Thirty trials were conducted for each of the five outlets (N = 150), and the wall chamber was decontaminated between trials. Results of an analysis of variance suggest wall service outlets allow spore penetration. The penetration factor for the telephone outlet was significantly greater than all other outlets (p < 0.05), and there was no difference in penetration between electrical outlets with and without plugs. Penetration factor differences were attributed to air leakage rates across the outlets. Due to the experimental design and equipment limitations, further research is needed to support these findings.
Insights
This pilot study found that fungal spores can penetrate wall service outlets, with telephone outlets showing the highest penetration rates. Air leakage appears to be a key factor influencing spore entry into buildings.
Area of Science:
- Environmental Microbiology
- Building Science
- Indoor Air Quality
Background:
- Fungal spores are common indoor air contaminants.
- Service outlets in walls may act as pathways for contaminant ingress.
- Understanding penetration routes is crucial for controlling indoor bioaerosols.
Purpose of the Study:
- To quantify fungal spore penetration through common wall service outlets.
- To compare penetration rates among different types of outlets.
- To identify factors influencing spore entry via wall penetrations.
Main Methods:
- A laboratory-controlled pilot study using a fabricated wall chamber.
- Aerosolization of Penicillium chrysogenum spores under constant air pressure.
- Microscopic enumeration of spores penetrating telephone, electrical, and cable outlets (N=150 trials).
Main Results:
- Wall service outlets permit fungal spore penetration.
- Telephone outlets exhibited significantly higher penetration factors than other types (p < 0.05).
- No significant difference in penetration was observed between electrical outlets with and without plugs.
Conclusions:
- Service outlets, particularly telephone types, can be entry points for airborne fungal spores.
- Air leakage rates across outlets correlate with spore penetration.
- Further research is recommended to validate these findings and explore mitigation strategies.
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