The media would like you to think that black mould is stalking you at every turn, suffocating you with its vile spores. But it’s really not the evil poison it’s made out to be.
Mould in your home is not good for your health, or the longevity of the building either. It’s a symptom of poor construction, lack of airflow, bad insulation, and not enough heating. While tenant occupants get a bad rap for not opening windows enough, it’s rarely the problem; it’s the poor quality of NZ’s housing stock, with homes not fit for the climate.
A survey showed that 35% of renters had some mould decontamination. 70% of them aired their house regularly and used cleaning agents like bleach to try and kill the plant (which doesn’t work, they should use vinegar).
In NZ, we have a few main mould types that you might find in your home. They all need a nice undisturbed space to grow, with a damp environment and plenty of food to eat. It’s important to note that all fungi inside can cause harm. The most at risk are the very young or old, immune compromised, or those with lung disease. Health problems from all fungi could include:
- Skin rashes
- Itchy eyes
- Sneezing
- Sinus headaches
- Breathing problems
It’s important to note that you cannot identify the type of mould in your home just by looking at it. You’d need to look at it under a microscope – although there are apps being developed that will use AI to identify your specific mould visitor. Until then, you’ll have to get the professionals in to test.
Stachybotrys Chartarum ‘Black Toxic Mould’
This is the mould that is called ‘toxic mould’. It’s present in about 3% of buildings that have mould, so it’s pretty rare. It brings friends with it too, usually aspergillus.
It’s a greenish-black colour, and it likes to live on things that have a high cellulose content, like paper, fibreboard (engineered wood), and gypsum (GIB board). It is slow growing and requires high levels of moisture.
While it’s called, rather dramatically, toxic, it really isn’t the horrendous villain it’s made out to be. Modern research has classified it as ‘biological risk group 1’, which is an agent not associated with disease in healthy people.
All mould types release spores, and these can irritate some people. Stachybotrys Chartarum has been linked to some upper and lower respiratory tract symptoms, but there’s no evidence to show it causes airflow obstruction, acute idiopathic pulmonary hemorrhage, chronic obstructive pulmonary disease, pulmonary hemorrhage, neurologic effects or cancer. So it can make those prone to allergies sneeze, cough, give you a runny nose, red nose, and even could cause a rash. In those predisposed to asthma or with compromised immune system, it can trigger asthma attacks.
Penicillium
You’ll typically find penicillium on fruit. It likes to live on soil, vegetation, and seeds and grains. But, it’ll live happily on your walls, ceilings, and HVAC systems too, it is robust and doesn’t need huge amounts of moisture to survive.
It’s famous for being turned into the antibiotic penicillin, so it’s probably the most famous mould. It’s also one of the most common moulds you’ll find at home.
Aspergillus
While most commonly found in seeds, grains, soil, and decaying vegetation, aspergillus is happy enough living inside your home too. It’s one of the most common fungi types found in the home, and outside too- you’ll breathe this fungi in every day.
Aspergillosis is an infection called by aspergillus mould spores. While most people breathe in these spores every day are don’t get sick, for some with weak immune systems and lung diseases, they are at risk of illness. The spores invade areas of the body and can cause harm.
Aspergillosis can cause allergic reactions, lung infections, and these infections can grow to other organs of the body. Allergic bronchopulmonary aspergillosis (ABPA) affects up to 15% of cystic fibrosis patients, and about 2.5% of asthma patients. chronic pulmonary aspergillosis (CPA) affects about 400,000 people per year. Invasive aspergillosis is another infection but this is rare as it requires specific pre-existing illnesses in the patient.
Cladosporium
This common fungi likes tomato leaves, or any living or dead plant material including cereals, peanuts, and refrigerated meat. The spores can be extremely abundant indoors, and can cause skin infections, sinus and lung problems, and the usual nasal congestion and itchy eyes. While they don’t produce mycotoxins, they do release volatile organic compounds (VOCs), which give them that rotting smell.
It’s in the top three airborne fungi, after penicillium and aspergillus.
Fusarium
This is a fungi that lives in soil, plants, water, and other organic materials. If the mould comes inside, it can grow under carpets, behind wallpaper, and inside walls. It doesn’t like being inside though, and you’ll most commonly ingest it by eating it, rather than inhaling it.
However, it’s pretty rare to be floating around in your home.
Mould is a valid health concern. However, due to the relationship with cold indoor temperatures and high levels of indoor moisture, it’s hard to tease apart the harm that mould causes without those other factors.
All moulds should be treated with respect in regards to potential health risks, and removal should be a priority. It’s not necessary to determine the type of mould; simply eliminate it.
