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Dr. Jackson Kung’u (PhD)- Mold Specialist.
Phone: 905-290-9101

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mold exposure

Mold Exposure: Symptoms of Mold Allergy

Mold exposure does not always present a health problem indoors. However some people (about 20% of the human population) are sensitive to molds.  Symptoms of mold exposure are primarily allergic reactions involving the upper respiratory system. Also referred to as mold allergy, the symptoms can include:

  • Sneezing
  • Runny or stuffy nose
  • Cough and postnasal drip
  • Itchy eyes, nose and throat
  • Watery eyes.

Symptoms of mold exposure vary from individual to individual, and range from mild to severe. Some individuals may have year-round symptoms or symptoms that flare up only during certain times of the year when the allergens are present. Currently no exposure limits have been established. The large number of mold species and strains present in the environment and the large inter-individual variability in human response to mold exposure make it difficult to establish exposure limits.

For individuals with mold allergy and asthma, their asthma symptoms may be triggered by exposure to mold spores. In some people, exposure to certain molds can cause a severe asthma attack. Signs and symptoms of asthma include:

  • Coughing
  • Wheezing
  • Shortness of breath
  • Chest tightness.

On some rare occasions, effects of mold exposure may include infections and toxic effects. Serious infections from living molds are relatively rare and occur mainly in people with severely compromised immune system. Many types of molds may produce toxins but only under certain growth conditions. Toxic effects have been reported from eating moldy grain, but evidence is weak that inhaling mold spores in buildings causes toxic effects.

Prevention of mold exposure and ensuing health issues include control of mold growth in the first place by rectifying the moisture problems. Failure to completely dry out building materials after extensive flooding and water damage can result in extensive mold growth.

If you are concerned about mold exposure, check your home to make sure there are no hidden areas of mold growth. Speak to your doctor if you have had previous mold exposure, and discuss any symptoms you may be experiencing.

Indoor Air Quality – Testing For Mold

The health effects of poor indoor air quality are dependent upon several factors including the type of contaminant, concentration, duration of exposure, and individual susceptibility. Indoor air quality can be compromised by a number of contaminants including mold.

Assessing the status of Indoor Air Quality

The status of indoor air quality is assessed by measuring the levels of contaminants indoors. These Contaminants include:
1. Biological contaminants such as mold, bacteria, viruses, etc.
2. Chemical contaminants such as formaldehyde.

This article is focusing on mold as an indoor air contaminant. Contamination of air by mold spores can easily be determined by air testing.

Testing Air for Mold

There are two methods commonly used to test air for mold. These are:
1. Viable or culturing air testing

2. Non-viable or total spore count air testing.

Assessing the Status of Indoor Air Quality by Viable Air Testing.

For viable air testing, air sampling can be conducted in two ways. The first method uses settle plates. This technique involves opening agar plates inside the area being tested and leaving them open for half an hour or more. Airborne mold spores and hyphal fragments settle by gravity onto the agar plates. Any viable spores or hyphal fragments would then grow into visible colonies that can be counted and identified. A high colony count is an indication of poor indoor air quality. This method is cheap since all it requires is agar plates. However, it’s not an efficient way of testing for mold spores in the air. The second method uses an air sampling pump. In this case, air is impacted onto the agar plates by a pump. This method is more efficient since it doesn’t depend on free-falling of spores into the agar. Viable testing for mold has a big disadvantage in that it only detects viable spores/hyphal fragments yet even dead spores are a health hazard.

Assessing the status of Indoor Air Quality by Non-viable Air Testing.

Non-viable air testing samples are collected by impacting air on an inert surface coated with an adhesive. Most of the spores and other particulate in air get stuck on the adhesive surface. The samples are then tested by direct microscopy. The spores and/or other particulates are enumerated and identified. The results are reported as spores per cubic meter of air. This method of sampling requires an air sampling pump such as BioPump and air sampling cassettes such as Air-O-Cell or allergencos. The major advantage of this method is that both viable and non-viable airborne spores and other particulates are enumerated thus giving us a better idea of the status of the indoor air quality.

Health Effects of Mold

All molds are potentially a health hazard. While majority of common molds are not a concern to individuals who are healthy, the health effects of most of the indoor molds are not known. Some symptoms associated with mold exposure are also highly controversial. Health effects of mold include:

1. infection;

2. allergic reactions (i.e., allergy);

3. mycotoxin poisoning.

 Infection

Infection of healthy individuals by indoor molds is very rare. Occasionally, however, immunocompromised individuals may be infected by some opportunistic pathogens such as species of Aspergillus, Penicillium and Fusarium.

Allergic Reaction

It’s estimated that about 20% of the human population is allergic to normal spore concentrations. The rest 80% would require exposure to higher spore concentrations. Health effects of mold partly depends on the amount of mold an individual is exposed to. However, with the large number of mold species and strains growing in buildings and the large inter-individual variability in human response to mold exposure it’s hard to define what is “normal” or “high” mold spore concentration.

Mycotoxins

Apart from infections the most well known health effects of mold is mycotoxin poisoning. Some common molds such as Aspergillus flavus, Stachybotrys chartarum, Fusarium, Alternaria, Paecilomyces, Rhizopus, Trichoderma, and Trichothecium produce substances (mycotoxins) that are toxic to humans, animals or other microorganisms. A number of mycotoxins are not only toxic but are also highly potent carcinogens. Spores of toxin producing molds contain mycotoxins. Majority of mycotoxins are not volatile and therefore mycotoxin exposure is likely to occur through inhalation of spores and dust. Evidence that inhaled mycotoxins affects human health is circumstantial.

Minimizing Exposure To Mold

The best way to deal with the health effects of mold is to minimize exposure to mold. Exposure to mold can be minimized by improving the indoor air quality. Here are some steps one can take:

  • Controlling humidity and letting more air into the house by ensuring sufficient ventilation. This prevents moisture from building up on walls and windows. If there is excessive humidity, mechanical ventilation such as a fan may be needed to get rid of it.
  • Measuring humidity by using a hygrometer to see if a de-humidifier is needed. The relative humidity should be kept below 50% in summer and 30% in winter.
  • Repairing leaky roofs, walls, and basements.
  • Cleaning moldy surfaces with a detergent.
  • Keeping the house clean and dust-free.
  • Regularly cleaning and disinfect humidifiers, de-humidifiers, and air conditioners.

If you have a question regarding health effects of mold, contact us at 905-290-9101.

Mold Exposure Limits

Question: My question regards mold exposure limits. I just had a mold count done in my home. The spore count levels in the basement were 5X and 6X outside air in the bedroom. Are these levels high enough to make someone sick? What are “high” levels? In other words are there mold exposure limits? Molds found were Penicillium, Aspergillus and ascospores. I spent a good deal of money on the testing and just would like someone else’s point of view, other than the guy wanting to sell me the remediation. Thank you.

Answer: Due to the large number of mold species and strains commonly found in buildings and the large inter-individual variability in sensitivity to mold exposure it has been difficult to set mold exposure limits. In other words there are no safe or unsafe levels of airborne mold spore counts that have been established. In absence of mold exposure limits, results from tests for airborne fungal spores cannot be used to assess risks to the health of building occupants. However, individuals who are immunocompromised are at higher risk of mold exposure than healthy individuals.

To minimize the risks of mold exposure it’s recommended to:

  • control humidity and diligently repair any water damage to prevent
    mold growth; and
  • clean thoroughly any visible or concealed mold growing in
    residential or office buildings.

These recommendations apply regardless of the type of mold found to be growing in the building.

Exposure limits to black mold

Many times we’re asked the exposure limits to black mold. Unlike other indoor pollutants, there are no exposure limits to mold. Exposure limits to mold would be difficult to set because human beings differ in their susceptibility to mold. Similarly, the molds themselves differ in their ability to cause health problems.

Molds may affect human beings in three different ways:

  • Allergenicity
  • Infection
  • Toxicity

As concerns common indoor molds the most likely effect is allergenicity. Very few fungi (molds and yeasts) are known to cause infection to healthy individuals. Toxicity is most likely to occur if one eats food contaminated with the fungal toxins. While toxicity is also possible through inhalation of spores or dust containing toxins, little is known about this possibility. 

Generally, elderly people, infants, sick people and other individuals with weak immune systems are at higher risk of suffering from mold exposure related diseases than healthy people.