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MOLD - HYPE OR HEALTH HAZARD, by Jack Eastland, CWS, CSRS

The short answer is some of both.

Being paranoid does not mean that you don’t have any enemies.  We know more about molds than we understand.  We know that molds are a sub group of fungi.  Fungi are neither plants nor animals.  They include molds, mildews, yeasts, and mushrooms.  Some are helpful.  Without yeasts, we would not have beer.   Without mold, we would not have penicillin.  Molds bread down organic material.  Without molds, we would be covered over in dead leaves and grass.  Some are harmful.   Some mushrooms are poisonous.  Some molds will make you sick.

Scientists have identified over 70,000 species of fungi and estimate there may be 10,000,000 more to be identified.  Of the 70,000 fungi identified, not one evolved to live indoors!  That is why mold is always around us but seldom a problem anywhere but indoors.

Mold requires three things to grow-moisture, still air, and food.

Mold cannot grow on clean concrete, tile or grout.  It can grow on tiny amounts of residual from oil, oils in fingerprints, soap residue, dead skin cells, or any organic material that is on the concrete.  This means that mold can grow in almost any human environment.  It may flourish on only microscopic amounts of food.  The fact that you do not see the food does not mean that it is not there.

Poorly ventilated areas are everywhere. Air can move slowly in basements, crawl spaces, closets, corners, bathrooms, and even parts of otherwise well ventilated rooms.  Behind a chair, or behind a picture, are places that mold can grow in an otherwise well ventilated room.

If an area is dry, mold will not grow.  Mold is the symptom, moisture is the problem.  Mold can survive on atmospheric moisture alone.  Relative humidity of 50% can support mold growth.

Since mold has always been with us, why is it a problem now?  If it is OK in the yard, why is it a problem in the house?

The short answer is energy cost!  In the days of cheap energy, insulation was minimal and if circulation solved most of the problem.  As we improved insulation, stopped air infiltration, and increased furnace efficiency, we reduced the amount of air exchange.  By doing this we concentrated the mold spores in the house.  Remember, mold spores are tiny (microscopic) and can remain airborne for a long time.  Mold can grow nicely in a dirty furnace filter.
 
As mold and mold spores concentrate, we have two problems.  The concentration alone can contribute to allergic reactions.  Worse still are competition beween mold colonies.  We know that different species of ants will fight each other over food sources.  Dogs will fight over a bone.  Mold colonies fight each other also.  Lacking teeth and claws, they use chemical surface.  Some mold types give off toxic substance intended to kill other mold species.  The fact that these harm humans is incidental and probably classed as “COLLATERAL DAMAGE”.

Is there health effects attributed to mold? 
Yes!  They fall into one of several categories:

Allergic reaction is by far the most common health effect.  Inhaling mold spores often cause and allergic reaction.  Bear in mind that a two cubic inch area can contain millions of spores.  Allergic reactions are usually, but not always, mild.  Runny nose, itching eyes, and rashes are common reactions.

Asthma can be triggered or aggravated by mold spores.

Hypersensitivity pneumonitis is a lung problem triggered by mold.  This can mimic some of the symptoms of pneumonia.

Mitological Volatile Organic Compounds are irritants that may cause legitimate but non-specific complaints.  Medical science recognizes that there is a cause and effect relationship but cannot identify the specifics.

Opportunistic infections have been recorded in very young children, older people, and those with compromised immune systems.

Mycotoxic reactions are fungal poisons and are documented in animals, but little research has been done with humans.  Mold contaminated hay has been known to kill horses.

Reactions to mold can range from none to minor to major to fatal depending on the individual.  In many individuals, the effects are cumulative.  That means the first hundred exposures may have no effect and the next one will cause a reaction.