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Know the Health Concerns of Indoor Mold in Alberta

Knowing what type of mold you have in your home or workplace may be helpful in understanding certain sensitive allergic reactions you or others may experience.

Disclaimer: Diagnosis of a particular health effect should be left to a medical professional. Health effects in general are not well studied, and dosage, exposure, and sensitivity thresholds are not well known and can potentially vary tremendously depending on various conditions and on the particular individuals. Effects will also vary from species to species within a particular mold genus.

Mold Health Concerns

Your usual exposure to mold is through the air and becomes a concern of indoor air quality if you are sensitive to the mold spores. In the short term, most healthy people don’t notice physical effects. With long-term exposure, the most common complaints are coughing, itchy eyes, stuffy nose, sneezing, and sore throat.

If you are sensitive to mold or have a weakened immune system, exposure can be a problem. Mold health concerns can be broken down into three different types: allergy, toxin and infection.


The most common effect of mold exposure is allergenic, with hay fever and respiratory symptoms the most common health effects of mold in indoor environments. Ranging from hay fever and asthma all the way to diseases in certain organs or tissues, mold allergies can also cause lack of concentration, fatigue and headaches.

Major indoor allergens include: Cladasporium, Alternaria and Ulocladium.


Molds produce chemical by-products called fungal toxins. These mycotoxins are the molds’ natural defence systems that are released when the mold is threatened. The effects of the toxins can show up in a wide variety of symptoms. These toxins may have negative health effects, such as lung inflammation with flu-like symptoms, infections of the upper airways, sinusitis or lung diseases.

Major indoor toxin producers: Stachybotrys, Memnoniella, Trichoderma, Aspergillus, Penicillium and Fusarium.


Some molds are infectious, but fortunately many molds won’t even grow at normal body temperature. Infections from mold in healthy individuals are rare, but mold infections can be dangerous in people with immune system weakened by AIDS, certain cancers and certain drug therapies. Mold can infect the mucus membranes, throat, lungs, skin and eyes.

Major infectious indoor molds: Aspergillus, Fusarium, Zygomycetes, including Mucor and Rhizpous.

Stachybotrys you may know from news reports as “black mold.” It can have toxic effects on animals, but the exact danger to humans is not clear.

It has been linked to ‘bleeding lung disease’ pulmonary hemorrhage.

  • Stachybotrys chartarum is known to produce a variety of mycotoxins. There is significant variation among isolates of Stachybotrys chartarum in the production of mycotoxins and other metabolites. Scientists are still studying Stachybotrys chartarum with the aim of understanding what the mold is comprised of.

Memnoniella, Ulocladium and Chaetomium are indicator molds that grow under the same conditions as with Stachybotrys. They have their own toxigenic properties that haven’t been studied.

  • Little is known about the medical significance of Memnoniella echinata. However, it produces many of the toxins produced by Stachybotrys chartarum, suggesting that Memnoniella echinata should also be considered unhealthy in indoor air.
  • Ulocladium has been reported to cause Type I (hay fever) allergy. There have been cases of Ulocladium chartarum causing skin surface and deep skin infections in immuno-suppressed patients.
  • Species of Chaetomium are known to produce mycotoxins but to what extent these toxins contribute to poor indoor air quality or affect human health is not documented.

Trichoderma is an indoor mold that grows on materials like paper and various ceramic items found in kitchens. Patients with suppressed immune systems have been affected by Trichoderma, but allergic reactions are rare.

  • Human infection by species of Trichoderma is limited to individuals with severely weakened immune systems. However, some species such as T. harzianum and T. viride are producers of potent mycotoxins.

Aspergillus is found around the world as an allergen, contaminant and opportunistic pathogen. It can cause the dangerous disease Aspergillosis in people with compromised immune systems, but doesn’t usually pose a health threat to those with normal immune systems.

  • Medical Effects: As concerns health, the most important species of Aspergillus are Aspergillus clavatus, A. flavus, A. fumigatus, and species from the group of A. niger, and A. versicolour. These molds have been classified by some authorities as being toxigenic or pathogenic and steps should be taken when they appear in occupied indoor environment.
  • Mycotoxins: Aspergillus species produce toxic compounds, the most well known being aflatoxins. Aflatoxin is a class 1 carcinogen produced by strains of Aspergillus flavus and Aspergillus parasiticus. The best known toxic metabolites of A. fumigatus are mainly fumigaclavines A, B, C, and D, spinulosin and tremorgenous toxins, e.g. verruculogen. A. niger strains produce toxic metabolites belonging to malformins A1, A2, B1, B2, C and oxalic acid. On building material, strains of A. versicolour produce the toxic class 2A carcinogenic sterigmatocystin.
  • Opportunistic Pathogens: Aspergillus fumigatus is an animal and human pathogen causing a group of diseases commonly referred to as Aspergilloses. Aspergillosis of the lungs is believed to be the most serious of these diseases and is quite common in birds and various mammals including humans. Other species of Aspergillus associated with Aspergillosis are A. flavus, A. niger and A. terreus. Aspergillus niger has been reported as causing ear, nose and lung infection particularly in immuno-compromised individuals.
  • Allergic Reactions: Many species of Aspergillus produce dry, hydrophobic spores that are easily inhaled. Due to their small size, about 70 % of spores of A. fumigatus are able to penetrate into the trachea and primary bronchi and close to 1 % into alveoli. Inhalation of spores of Aspergillus is a health risk. Aspergillus clavatus is allergenic causing the occupational hypersentivity pneumonitis known as malt worker’s lung.

Penicillium: It is an allergen and can cause infections in people with weak immune systems. Some varieties produce unhealthy toxins.

  • About 200 species of Penicillium have been described. They are commonly called the blue or green molds because they produce enormous quantities of greenish, bluish or yellowish spores which give them their characteristic colours. Spores from this species of mold are found everywhere in the air and soil.
  • Penicillium chrysogenum is the most common species in indoor environment. It is widespread and has a wide range of habitats. In indoor environment, it is extremely common on damp building materials, walls and wallpaper, floor, carpet mattress and upholstered furniture dust. It produces a number of toxins of moderate toxicity. It is allergenic (i.e., it can trigger allergic reactions).
  • Some species of Penicillium can also infect immune-compromised individuals. For example, P. marneffei is pathogenic particularly in patients with AIDS and its isolation from blood is considered as an HIV marker in endemic areas.
  • Penicillium species other than P. marneffei are commonly considered as contaminants but they are also known to produce mycotoxins. For example, P. verrucosum produces a mycotoxin, ochratoxin A , which is damaging to the kidney (nephrotoxic) and could be cancer causing (carcinogenic). The production of the toxin usually occurs in cereal grains at cold climates but has been isolated in buildings contaminated with Penicillium. Other mycotoxins include patulin, citrinin, and citroviridin among others.

Fusarium: If you have a weakened immune system, Fusarium can pose an infection risk.

  • Fusarium solani, Fusarium verticillioides causes keratitis in humans. It is also associated with wounds and infections of the eyes and fingernails. It poses inhalation and deep skin (dermal) inoculation health risks to persons with weak immune systems. It also poses health risks related to major barrier breaks such as corneal perforation, major surgery, peritoneal or venous catheter presence, and injection drug use.

Cladosporium triggers hay fever, asthma and other allergy symptoms.

  • Species of Cladosporium are not human pathogens except in some cases of immuno-compromised patients. However, Cladosporium species have the ability to trigger allergic reactions to sensitive individuals. Prolonged exposure to elevated spore concentrations can elicit chronic allergy and asthma.

Contact Advanced Remediation Solutions Inc. in Edmonton for more information and to schedule a mold assessment. We perform mold removal throughout Alberta.

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