Mould toxin could areosolise directly into the air: study

Toxins from mould could aerosolise directly into the air, which could explain one cause of sick building syndrome, French researchers said yesterday.

Mould growing in buildings could make people sick, especially people who were allergic to various fungi. It was also known that various moulds and fungi produced mycotoxins - chemicals that could sicken and even kill people and animals.

However, what was not entirely clear was how mould growing in and on walls or elsewhere in buildings might make people sick.

Jean-Denis Bailly of the University of Toulouse in France and colleagues tested three common types of fungi that could grow inside buildings and found that their mycotoxins could and did disperse into the air until normal conditions.

''These toxins can subsequently be aerosolised, at least partly, from mouldy material,'' they wrote in their report in the journal Applied and Environmental Microbiology, published by the American Society for Microbiology.

''This transfer to air requires air velocities that can be encountered in 'real life conditions' in buildings.''

They tested three species - Penicillium brevicompactum, Aspergillus versicolor and Stachybotrys chartarum, all of which grew on wallpaper in their lab. The species also produced mycotoxins.

The researchers simulated airflow over a piece of wallpaper contaminated with three species of fungus often found indoors.

"Most of the airborne toxins are likely to be located on fungal spores, but we also demonstrated that part of the toxic load was found on very small particles -- dust or tiny fragments of wallpaper, that could be easily inhaled," said Bailly.

Thought mycotoxins were better known for their occurrence in food, the ''presence of mycotoxins in indoors should be taken into consideration as an important parameter of air quality," he said.

Applied and Environmental Microbiology, a journal of the American Society for Microbiology has published the study.

According to Bailly and his colleagues, creating an increasingly energy-efficient home might aggravate the problem.