What is mold? Strictly speaking, “mold” (or “mould” in British spelling) is more of a colloquial name rather than not a proper scientific term. This name applies to fungi having a specific “moldy” look. Fungi, in turn, are one of the six major divisions of living organisms, kingdoms, along with animals, plants, protists and two groups of bacteria. The fungal kingdom includes mushrooms, yeasts, plant pathogens, molds and numerous other groups less known to general public. None of these categories is confined to a certain taxonomic group, in other words, a group having common evolutionary ancestors.
Fungi typically referred as mold are the ones able to grow relatively fast on food and building materials and having furry or velvety appearance. Mildew is another colloquial name commonly used alongside with mold. It means about the same but applies to the fungal growth looking powdery or slimy.
In order to grow, molds require food, water and appropriate temperature. Different mold species have different food preference but overall they are not picky and can contain majority of organic chemicals. Cellulose, one of major components of drywall and wood, can serve as the sole source of nutrition for most of them. Plasters often contain organic additives that make them also susceptible to mold growth. Normal indoor temperature is perfect for mold growth. Therefore these two conditions are almost always fulfilled. Water is the key factor though. Moisture of building materials inside human dwellings should not really be at a level sufficient for mold growth. However, moisture level does happen too high occasionally due to diverse reasons. These reasons could be straight-forward and easily fixable such as pipe and roof leaks or pretty intricate such as improper design of HVAC system. In bathrooms and basements excessive moisture may be hardly manageable and, in this case, elimination of food source would be a solution.
Many common indoor molds are known to be so-called opportunistic pathogens. That means that they do not infect healthy individuals but do infect the ones with weakened immune system such as AIDS patients and people with organ transplant who have to take immunosuppressants in order to prevent rejection. More often, the malicious effect of indoor molds is caused by their production of allergens or toxins. Potential allergens are produced by a broad variety of indoor molds but susceptibility to them greatly varies from person to person. Allergic responses include hay fever-type symptoms, such as sneezing, runny nose, red eyes, and skin rash. Toxins produced in sufficient for causing an adverse health effect dose by a smaller number of indoor mold species. The most important toxic molds are two species commonly occurring in conditions of high consistent, Stachybotrys chartarum and Chaetomium globosum. Many symptoms and human health effects attributed to inhalation of mycotoxins have been reported including: mucous membrane irritation, skin rash, nausea, immune system suppression, acute or chronic liver damage, acute or chronic central nervous system damage, endocrine effects, and cancer. Mold products can also cause or contribute to asthma acting either as allergens or non-allergenic irritants.
Microbial volatile organic compounds (MVOCs) are another group of chemicals produced by fungi as well as other microorganisms. Unlike toxins and allergens adherent to mold particles, their molecules, due to low weight, can penetrate through completely sealed but porous buildings structures. MVOCs are responsible for moldy or earthy smell. However, currently, there is no scientific evidence of their health implications.
Fungi typically referred as mold are the ones able to grow relatively fast on food and building materials and having furry or velvety appearance. Mildew is another colloquial name commonly used alongside with mold. It means about the same but applies to the fungal growth looking powdery or slimy.
In order to grow, molds require food, water and appropriate temperature. Different mold species have different food preference but overall they are not picky and can contain majority of organic chemicals. Cellulose, one of major components of drywall and wood, can serve as the sole source of nutrition for most of them. Plasters often contain organic additives that make them also susceptible to mold growth. Normal indoor temperature is perfect for mold growth. Therefore these two conditions are almost always fulfilled. Water is the key factor though. Moisture of building materials inside human dwellings should not really be at a level sufficient for mold growth. However, moisture level does happen too high occasionally due to diverse reasons. These reasons could be straight-forward and easily fixable such as pipe and roof leaks or pretty intricate such as improper design of HVAC system. In bathrooms and basements excessive moisture may be hardly manageable and, in this case, elimination of food source would be a solution.
Many common indoor molds are known to be so-called opportunistic pathogens. That means that they do not infect healthy individuals but do infect the ones with weakened immune system such as AIDS patients and people with organ transplant who have to take immunosuppressants in order to prevent rejection. More often, the malicious effect of indoor molds is caused by their production of allergens or toxins. Potential allergens are produced by a broad variety of indoor molds but susceptibility to them greatly varies from person to person. Allergic responses include hay fever-type symptoms, such as sneezing, runny nose, red eyes, and skin rash. Toxins produced in sufficient for causing an adverse health effect dose by a smaller number of indoor mold species. The most important toxic molds are two species commonly occurring in conditions of high consistent, Stachybotrys chartarum and Chaetomium globosum. Many symptoms and human health effects attributed to inhalation of mycotoxins have been reported including: mucous membrane irritation, skin rash, nausea, immune system suppression, acute or chronic liver damage, acute or chronic central nervous system damage, endocrine effects, and cancer. Mold products can also cause or contribute to asthma acting either as allergens or non-allergenic irritants.
Microbial volatile organic compounds (MVOCs) are another group of chemicals produced by fungi as well as other microorganisms. Unlike toxins and allergens adherent to mold particles, their molecules, due to low weight, can penetrate through completely sealed but porous buildings structures. MVOCs are responsible for moldy or earthy smell. However, currently, there is no scientific evidence of their health implications.