Monday, November 16, 2015

Common Mold Types found in Southern California - Aspergillus

It’s coming!  It’s coming!   Wha…?!  Huh?!  El Nino!  Who?  A lot of rain!  Okay.  There are technical explanations for what El Nino is and what causes it, but suffice to say that its source is a change in temperature of a large portion of the Pacific Ocean.  This causes high pressure in the western Pacific and low air pressure in the eastern Pacific.  This brings on heavy rainfall in the eastern Pacific area and low rainfall in the western Pacific area.  So the bottom line is that El Nino means very heavy rains here in California.  Excessive rainfall generally causes more water intrusion into buildings and resulting mold growth

Often “fungus” and “mold” are confusing as terms as they are sometimes used interchangeably. “Fungus” is a more general term.  Fungi include molds, yeasts and macro-fungi like mushrooms, puffballs, etc. 

Water damage inside your home or office whether known or unknown can result in mold growth.  Exposure to molds particularly chronically can result in health symptoms.  Reactions can vary widely from person to person.  There are certain mold types that are commonly found due to water intrusion into building envelopes.  We will be featuring some of the most common experienced in Southern California.  With the advent of El Nino, this seems the opportune time for dealing with this subject.

Aspergillus – What is it?

In microscopic analysis, Aspergillus is often grouped with Penicillium.  That grouping is generally shown as Penicillium/Aspergillus or Pen/Asp.  The reason for this grouping is that the two spore types cannot be distinguished one from the other microscopically.  To differentiate the two requires seeing the underlying structure which often means culturing (or growing) the organism.

Aspergillus is found under normal conditions in soil, decaying plant debris, compost piles and stored grain. 

Indoors Aspergillus will grow on a wide variety of materials (substrates) including building materials, leather, and clothing depending on the amount of moisture present.  Aspergillus is often detected inside air conditioning systems especially on cooling coils and/or interior fiberglass liner.  On building materials Aspergillus is one of the first or primary invaders along with Penicillium.  Both can produce toxins for the purpose of discouraging other molds invading space they have already claimed.  It is speculated that some of these toxins could be harmful to humans, but this has never been clinically established. The primary invaders can be joined by a secondary invader, usually Cladosporium.  With a continuation of high levels of moisture, they can be overgrown by Stachybotrys or possibly Chaetomium.

Industrial uses include fermentation in some food and beverage production.  Some species are also used in combination with other materials to produce some drugs.  One species is able to decompose plastic.

What’s the harm?

While certain individuals can develop allergies to virtually any mold, research shows that Aspergillus species are known to cause a number of specific allergies.  Some of the more familiar health effects related to Aspergillus include asthma and hay fever.  Some allergies have names that are specific to certain professions or activities.  Some of these are:  Malt worker’s lung, Compost lung, Wood trimmers disease, Straw hypersensitivity, Farmer’s lung, Oat grain hypersensitivity.  The list is probably longer, but this should suffice as an introduction.

Some species of this mold type are quite important due to their ability to grow well at human body temperature.  All three of the ones I’m about to list can invade the body, grow where ever they manage to find a favorable environment and do damage there.

Aspergillus fumigatus will grow in the lungs resulting in fungus ball or Aspergillosis.  One of the evident symptoms is coughing up blood. 

Aspergillus flavus is known for nasal sinus lesions.

Aspergillus niger causes “Swimmer’s ear.”

It should be noted that for the most part these are “opportunistic pathogens,” meaning those with impaired immune systems are most vulnerable.  These Aspergillus species can be quite problematic in hospitals and other health care centers due to the susceptibility of patients.  When nosocomial (hospital caused) illnesses occur, testing for viable airborne Aspergillus spores should be conducted.  See my article, “Nosocomial Illnesses” at

While Stachybotrys, AKA “The Black Mold,” gets much of the publicity and is deservedly notorious, Aspergillus could be an even more important mold type due to its broader abilities to do harm.  Stachybotrys will be discussed in a future article.

What can be done about it?

The most effective way to deal with mold is to prevent water from entering the building envelope.  Given that this is impossible sometimes as leaks can occur no matter what you do, but be aware of potential roof leaks as well as leaking from plumbing fixtures.  Preventative steps should be taken, so look and take necessary action.

Also remember that exterior walls are not equipped to sustain prolonged direct impact of water.  That can break down the moisture shield causing water intrusion into wall cavities.  This can happen due to sprinkler water spraying directly onto the wall, but it can also occur due to prolonged rainy periods with wind causing impact on a particular wall. 

Once water intrusion does occur, remedies need to be applied as soon as possible.  The source of the water must be determined and eliminated at the source as possible.   During El Nino, wind driven rain water impacting on a wall might require a barrier to limit that impact.

Keep in mind that any sort of roof repair or other actions to keep rainwater from the building envelope is likely to be more difficult to obtain and more expensive due to the increased demand.  So take whatever preventative actions possible now.

Once exposed and suffering health effects, steroids and/or anti-fungal drugs including statins are often prescribed.  Side effects of these drugs, including suppression of the immune system, can be quite troublesome.  These drugs can be very toxic, especially to the liver.


Natural remedies include probiotics that can actually enhance the immune system.  Some spices are known to be anti-fungal.  These include garlic, ginger, cayenne and goldenseal.  Starving the fungi by avoiding certain foods is also recommended.  Anti-fungal diets are found in some publications such as Breathe Free or Die – The Layman’s Guide to Mold and Other Indoor Air Quality Problems, by Stephen Huff or The Fungus Link, by Doug A. Kaufmann.


Always consult one or more health care professionals before beginning any health remedy.


  1. So if you want to make sure that you will not spend any unnecessary money, get a contractor to install your air conditioner and also let them do maintenance when ever needed. This will lengthen the life of your device and save you hundreds in new appliances or repairs.

    Cooling Master

  2. I am really impressed by your good services of indoor air quality.This is too much knowledge about indoor air quality. Thank you so much for giving information.
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  3. I have been extremely busy in the last few months, so this is my first chance to get to the blog. I have several more articles on mold types. Thanks for your acknowledgement

  4. Molds are everywhere. They are fungi that grow where there is moisture, may that be inside or outside. I think dehumidifier is the best solution. If allowed to grow unchecked inside home, however, mold can result in damage to both the structure and health.

    1. That is true and a dehumidifier can be quite useful. An example is that dust mites do not survive well at humidity levels below 40%. And if you have a problem with condensation they help as well.

  5. Hi
    I am weighing the possibilities of starting a business consultancy on Indoor Air Quality.
    Can you give me an opinion?

    1. I guess that would depend on your business acumen as well as your knowledge of indoor air quality issues and cleaning of HVAC systems.

  6. Thanks for sharing information,People with airborne allergies and asthma need to purchase quality HEPA air purifiers(top air purifiers) and HEPA vacuum cleaners to keep their indoor air quality clean and free of floating allergens that include, dust, pollen and mold spores.


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