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Sampling For Airborne Fungal Spores

Reasons for Conducting Air Sampling For Fungal Spores

Air sampling pump
Air sampling

Sampling for airborne fungal spores may be conducted for a number of reasons including assessing the air quality, detection of pathogenic organisms, epidemiological surveys and predictions, detection of mycotoxin producing fungi, or detection and measurement of exposure to allergenic fungi and actinomycetes. Before sampling for airborne fungal spores it’s important to have a clear objective and the data that would meet that objective. Some of these objectives require counting and identification of the airborne fungal particulates. A well calibrated pump is therefore required. The method of sampling, the equipment and the media are determined by the data required. For example if one is interested in species identification, then they would collect culturable air samples using an Andersen or RCS sampler.

Methods for Sampling for Airborne Fungal Spores

Culturable Air Samples

If the air was sampled by impaction onto a growth media, then the samples are first incubated at suitable temperature followed by counting and identification of resulting colonies (if any). A number of factors may affect the reliability of the colony counts data. These include the suitability of the agar media used for sampling, colony density, and presence of fast growing isolates. Some agar media are highly selective and therefore would not suitable when the objective was to determine the diversity of fungal species in the air. If the colony density is very high, then counting becomes difficult. In the presence of fast growing isolates, slow growing isolates are masked and hence difficult to count.

Non-culturable Air Samples

The second method of air sampling is where the air is impacted on inert medium, usually a filter membrane or adhesive-coated slide. The collection medium is then analyzed by transmitted light microscopy (popularly known as direct microscopic examination), typically at 600–1000 × magnification. A number of different collection devices may be used for spore trap sampling of which the most common are slit or circular impactors such as the Air-O-Cell®, Allergenco D, Micro 5, Cyclex D and other similar cassettes. Mixed cellulose ester membrane (MCEM) filters are also occasionally used.

Choose Your Spore Trap Analytical Labs Wisely

Identification of airborne fungal spores to species can only be accomplished by an experienced mycologist. Similarly, spore trap analysis requires considerable skill and experience on the part of the analyst to identify spores accurately, and to differentiate them from other airborne particulate. In most cases identification of airborne fungal spores by direct microscopic examination is limited to genus. In some cases identification of spores to specific genus is difficult. A good spore trap analyst requires several years of experience. A recent multi-laboratory comparative study of spore trap analyses found that only 75% of commercial accredited labs could consistently identify correctly Cladosporium spores and only 50% could identify Aspergillus/Penicillium-like spores consistently. The level of experience required for species identification or spore trap analysis cannot be attained in a short time, and it cannot easily be acquired by individuals lacking advanced training in mycology or plant pathology.

Mold & Bacteria Consulting Laboratories is accredited by CALA to the Internationally recognized ISO/IEC 17025:2005. 

Do You Have Normal Mold Levels For Various Types Of Mold?

Question: Do you have the normal mold levels for various types of mold, i.e. Cladosporium cladosporioides? Thank you.

Answer: Currently there are no widely accepted normal airborne mold levels. Although no exposure standards have been established that relate health effects to specific airborne mold levels, there are concerns from public health agencies regarding exposure to mold. Much evidence exists indicating that indoor exposures to molds contribute to occupant respiratory disease and symptoms. Mold levels are used to give us an indication of whether the occupants are exposed to mold originating from indoor environment. According to the American Conference of Government Industrial Hygienists (ACGIH), indoor mold levels should be less than 1/3 of outdoors levels.  If indoor levels are above this amount, action should be taken to identify the source or location of mold growth and remove it.  It’s important to note that the outdoor levels of mold can vary quite a lot over the different seasons and even week to week and the same is reflected indoors.

In the literature, 3000 spores per cubic meter of air is quoted as the allergenic threshold for Cladosporium. More recently a figure of 4000 spores per cubic meter of air has been cited. For Alternaria, 100 spores per cubic meter of air is cited in the literature as the allergenic threshold.

It is normal to find mold spores in any indoor environment in the air and surfaces such as clothes, walls, and furniture.  Most of the time mold spores found indoors during a mold inspection is from outside sources and do not pose a hazard. Regular housekeeping cleaning helps keep mold levels low. Cleaning small areas of visible mold, like the mold around your shower, is important to maintain sanitary conditions.

References

  • Hollins, P.D., P.S. Kettlewell, M.D. Atkinson, D.B. Stephenson, J.M. Corden, W.M. Millington and J. Mullins. Relationships between airborne fungal spore concentration of Cladosporium and the summer climate at two sites in Britain. International Journal of Biometeorology Volume 48, Number 3, 137-141.

How Do We Find This Mold And Get Rid of It?

Question: My son is having a severe allergic reaction to this mold. How do we find it and get rid of it? Could he have gotten in by playing outside in the woods?

Answer: To be able to answer your question, we need more information about this mold. However, if you suspect mold in your home, you may consider bringing in a professional to conduct an investigation.

How Long do Mould Symptoms Typically Last?

Question: My question regards how long mould symptoms typically last. I have found what appears to be a mould growing on my window. It is gooey in texture and clear in colour. The window is often wet with condensation to the point it drips down continually for hours on end.

I am not sure if the jelly like characteristic of the mould is because of the water or because that is it’s composition. Recently the mould was disturbed by somebody in our room (they opened the window). My wife had just left the room for a while with our infant daughter (10 months) for medical reasons as this person had to come in. When she came back into the room fifteen minutes or so passed when her nose started running. Being allergic to mould she immediately told me it had been disturbed and she could smell it. She now has had for the last four days what appears to be cold like symptoms. Are these mould symptoms? What should we do? How long do mould symptoms typically last? Does my description of the mould sound at all like anything particularly dangerous? Would this be a danger to our daughter? We don’t actually have anywhere else we could live so this is important to us how we handle it. Could putting plastic window covering that seals with heat keep it from the room or would it disturb it too much? It wasn’t here in the summer but seems to have happened from the washing that we’ve hung in the room drying without any ventilation. We’re concerned for our daughter so if you could let us know asap we’d so appreciate it. As I said, we live in this room and she is in the room nearly 24 hours every day. Thank you for your time.

Answer: I haven’t found any scientific literacy that documents how long mould symptoms last. In my opinion, this could depend on the extent of damage the mould had done on an individual’s health or immune system. The extent of damage will depend on an individual’s resistant to mould exposure. Some people experience mould symptoms only when they are in a mouldy environment.

From the description you’ve given, it’s difficult to tell what type of mould it is and whether it’s dangerous or not. However, all moulds are potentially a health hazard.

Covering the mould with plastic is not a good solution since spores could still find their way into the air you’re breathing. You’ve already identified the cause of the mould growth on the window, that is, condensation due to poor ventilation and the washing that you’ve been hanging in the room.  The solution is to correct the moisture problem and to clean the existing mould. I would suggest you look for a qualified professional who could advise you on how to improve the ventilation, reduce condensation, and also how to remove the mould without spreading spores in the room. Read “ Mold Removal Guidelines ” to learn more about mould removal.

After mould removal the mould symptoms your family is experiencing are likely to disappear.

Should I Seek Medical Attention?

Question: I have been sleeping in a damp room with a large amount of mold on the walls for about 4 months (which is in the process of being cleaned). Is this dangerous, should I seek medical attention even though I am in good health?

Answer: If you’re feeling OK then you don’t have to worry. However, I would suggest you have the mold cleaned up as soon as possible. Prolonged (long-term) mold exposure could cause health problems, including asthma, allergies or respiratory problems.

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