Fungi

Aspergillus niger

Aspergillus niger is a common species of fungi that forms as black mold on objects and food. This fungus is primarily found in soil, and prolonged exposure can cause painful, fungal ear infections as well as a severe lung disease known as aspergillosis. Aspergillus niger spores can easily migrate through the air and into building ventilation systems. Black mold deposits are often observed on aluminum heat exchangers in air handling systems which reduces efficiency in addition to putting inhabitants at risk. Aluminum is a common material used in air handling system components. Studies have shown that copper alloys inhibit the growth of this fungi.

Black Mold

Asperillus niger is a common species of fungi that forms black mold on dark, damp surfaces and food.  This fungus is primarily found in soil, and prolonged exposure can cause painful fungal ear infections, as well as lung disease known as aspergillosis.

Black mold deposits, whose spores can easily migrate through the air and into building ventilation systems, are often observed on aluminum heat exchangers in air handling systems.  These deposits can both reduce the efficiency of the air handling system and can expose occupants to risk for respiratory infections.  Studies have shown that copper alloys inhibit the growth of this fungus.

Air Conditioning Systems

In a paper presented in Letters in Applied Micrbiology 9, it was shown that copper offered an antifungal surface and prevented subsequent germination of spores present.  The study involved the inoculation of copper and aluminum specimens with fungal isolates (Aspergillus spp., Fusarium spp., Penicillium chrysogenum and Candida albicans) for various periods of time.  Cultures on potato dextrose agar and in-situ viability assay using fluorochrome FUN-1 were used to determine whether spores survived.  The results showed increase of die off of fungal isolates tested on copper compared to aluminum.  In addition, copper also prevented the germination of spores present, thereby reducing the risk of release of spores.  This work suggests that copper offers a valuable alternative to aluminum which could be used in air conditioning systems in buildings, particularly in hospital environments where patients are more susceptible to fungal infections.