This is a fungus that is typically dark green or black in color. It needs three things to live, which are: excessively high humidity levels, moisture, and organic materials to feed off of. It is commonly seen growing in basements and crawl spaces. When it grows, it releases spores up and into the air. Eventually, this air gets breathed in and it can cause a variety of health problems, including: respiratory problems, asthma attacks, cold/flu-like symptoms, and more.
It is often seen growing on substrates such as wood, wallboard, ceiling tiles, carpet, wall paper, paneling and leather items. Generally, any cellulose or porous material will grow the fungus under the right conditions.
Mycologists use the term “Mildew” only for fungi that grow on plants. When mycologists say “mildew,” they mean the white growth that causes diseases in plants.
“Yeast” grows naturally on habitats that are rich in carbohydrates. Examples include: wet grains (rice, millets, etc), potatoes, fruits, juices, etc.
The ability to identify between the three in your home is important since certain species of all three are known to pose a threat to human and animal health.
Authorities such as the CDC, EPA, and the U.S. Institute of Medicine all agree that fungus growth and associated dampness indoors is not acceptable. A home-based test can help identify dangerous fungus that is allergenic, infectious or toxic.
With a test, varying types of fungal sampling are done to determine:
Sampling for fungus is a pretty straight forward process and actually requires minimal training. However, a professional or environmentalist needs an understanding of building science to perform comprehensive investigations. It is important to understand why certain types of construction are prone to support growth of the fungus. A thorough investigation requires scanning the air to locate areas where elevated levels of fungi are most likely to exist and moisture readings to help identify red flag areas. This greatly enhances the ability of an environmentalist to properly perform a test. Specialized equipment is required for particle scanning and moisture measurements.
Accuracy of fungal testing varies greatly from laboratory to laboratory. Attention to detail is very important by laboratory technicians. A professional or environmentalist should occasionally check their laboratory’s accuracy by taking two identical samples in exactly the same location/spot and sending them to different laboratories to be tested. If the laboratory knows the environmentalist (their customer) occasionally cross-checks their work, the lab is more likely to take the required time to properly analyze the samples.
There are several different types of tests that can be performed, depending on the conditions in the environment and the specific information needed.
1) Petri Dish: A Petri or settling dish is an archaic approach to determine levels of air borne fungus. This fungus is everywhere outside and since outside air mixes with inside air, fungus is always present at some levels inside. A Petri or settling dish always collects mold spores. But since it does not meter and/or time the amount of air that passes over it, there is no scientific basis to determine if elevated fungal conditions exist inside buildings. Additionally, unlike large fungal spores, smaller spores stay air borne indefinitely and may not settle in a dish prior to laboratory test. It is also important to know the concentration and what type of non-viable spores are present. Settling dishes do not provide that information because only viable spores will grow in the Petri dish.
2) Tape Lifts: When you simply want to identify the types of fungi with a home test, surface samples taken with tape lifts or swabs are sufficient. They will identify different types of the fungus and can often indicate if there is active growth inside a building. Tape lifts are preferred over swabs when quantifiable tests are needed.
3) Bulk samples: This test involves small pieces of material thought be contaminated by fungus growth. They provide the same information as tape lifts or swabs but often require removing a piece of building material. It is especially effective in testing for elevated conditions in carpet. Since black mold (Stachybotrys) spores are very large and do not stay air borne very long it is sometimes missed by air sampling. Bulk sampling is effective in determining its presence.
4) Spore Traps: Fungal air samples are taken with spore traps. Samples are taken with a metered air pump so they may be compared to other control samples to be used as a comparison, such as a sample taken outside or in another room of the building. This test can tell us the concentration and type of fungal spores we are breathing and often indicate if there is active growth inside a building.
5) Wall Cavity Testing: Fungal air samples can also be taken with spore traps in wall cavities. This requires a small hole approximately one-half inch in diameter and is performed by inserting a vacuum tube into the wall.
6) Viable samples: Used to identify pathogens, viable sampling is done to capture live spores – usually metered air sampling with a culture that is incubated for several days. After a few days, this test can help determine whether or not the fungus is pathogenic – a disease causing or infectious fungus.
7) Control Samples: With the exception of a couple of states, no government standards or guidelines have been established to determine elevated or unusual levels of the fungus in buildings. That determination is made by the environmentalist or IDH (industrial hygienist) performing the investigation. Control samples are fungal air samples taken outside or in different areas of the building to assist in determining if unusual or elevated levels of fungi exist in a particular area of the building. There are some exceptions to this rule, i.e., there is zero tolerance for Stachybotrys.
1) Humidity levels above 60%: Warning signs of a problem can begin when indoor humidity is sustained above 60% for weeks at a time. If you suspect trouble, this would be an indication that you would need to contact a professional specialist.
2) When you think your home or office is making you sick: When people think their office or home is making them sick and they feel better when away.
3) When thinking about selling your home: Testing is recommended so problems can be eliminated before entering an agreement to sale a home. More home buyers are requiring testing prior to closing than ever before. Signs of the fungus can jeopardize a sale.
4) When there is a musty smell: A musty smell is a sign of growth. It’s always good to eliminate the growth in its early stages before it becomes a health problem or a costly remediation project. When selling a home a musty smell can be a turn-off for buyers.
5) After remediation/cleaning: Post testing should be done after a space or building has been remediated and cleaned to ensure the remediation company that preformed the work did a thorough job. The company performing the sampling should be independent of the company performing the remediation to ensure no more signs of fungus are present.
Negative air pressure containment areas should be built to encase areas prior to efforts to remove the fungus. HEPA (High Efficiency Particulate Air) scrubbers/filters capable of cleaning the air inside the containment area should be in operation continuously while work is taking place and for approximately seventy-two hours afterwards. This process cleans fungal spores from the air and prevents cross-contamination. At HealthyAir, we use standard EPA protocols for cleaning the contaminanted area(s).
Several processes and products to remove the problem have come into the market over the past few years. Dry ice and various other media products for machine blasting – also referred to as sand blasting – are used in extreme situations. But the vast majority of this kind of cleaning can be done by hand. HealthyAir recommends an EPA registered fungicide intended to remove the growth. Bleach will not kill it. It is important to choose cleaning products that actually kill spores so existing mold will not grow back. Of course, if conditions that sustained the growth are not eliminated new spores will eventually grow.
The following is an effective process to remove the problem areas in unfinished basements and crawl spaces:
A few months after I began inspecting buildings for mold I was asked by a real estate agent representing a potential buyer to test for mold in a four year old home. The home was bricked on all sides. On two sides of the home the finished basement was completely below grade with a third side about fifty per cent below grade.Read More View All
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