Let's continue our overview of the sources of biological indoor air pollution with molds, these microscopic fungi that grow in the presence of moisture.
When do molds develop?
As we explained in an article on dust mites, we coexist with many biological pollutants, most of which are invisible.
Enclosed spaces are favorable for the development of these micro-organisms. Moisture problems resulting from human activities are very common. The ambient humidity increases sharply during a shower, while cooking or when drying clothes.
This increase in humidity is favorable to the development of molds, which is why it is very important to properly aerate the bathroom after a shower or bath and the kitchen during the preparation of meals. Clothes coming out of the washing machine are soaked with humidity. As a result, drying laundry indoors produces a noticeable increase in humidity by the evaporation of the water contained in the clothes.
Well insulated buildings are very confined and humidity problems are more likely to occur because in many cases ventilation is not sufficient or has not been adapted following the insulation work.
Flooding or water damages equal to mould growth?
Another important source of molds is water damages. Simple leak or pipe rupture, water can infiltrate building materials (concrete, cement, plaster) and can lead to significant mold growth.
A flood following a natural disaster is also a situation that is all the more favorable to the development of molds because the waters can also contain large quantities of these organisms.
The development of molds is typically associated with a distinctive and unpleasant odor. It is caused by the emission of volatile organic compounds (VOCs) specific to molds: fungal VOCs.
However, the nature and quantity of these volatile and odoriferous chemicals do not allow us to identify the nature of the molds present. Only a laboratory analysis can identify and quantify the molds present and determine whether occupants are exposed to strains that are dangerous to health.
What are the health effects of molds?
Molds can induce several effects on the health of occupants. First of all, the presence of VOCs in the air induces ENT irritation and can cause breathing difficulties. Molds spores also contain allergenic proteins and therefore cause asthma attacks and respiratory allergies. In addition, certain strains of molds such as aspergillus are pathogenic and can develop in the respiratory tract and lungs in people at risk (immunocompromised or affected by severe respiratory diseases such as COPD Broncho-Pneumonia-Chronic-Obstructive). Finally, molds naturally produce small chemical molecules, mycotoxins such as aflatoxin, ochratoxin or patulin, which are extremely toxic to humans.
It is possible that a treatment with a fungicide-type pesticide may be used to solve the fungal development problem, which can eradicate one pollution by replacing it with another.
A search for mold in the dust makes it possible to accurately identify the nature of the molds and to evaluate the health risks of chronic exposure.
How to identify molds?
Tests with laboratory analysis are now available to carry out a complete assessment of fungal contamination in a home or office.