Photo by Reyer Boxem

Mould may be making you ill

Coughing, fevers, headaches

Photo by Reyer Boxem
With the heating turned down because of high energy prices, many student houses start to suffer from mould. And that can be a real problem. ‘The moment I stepped into the studio, I could smell it.’
5 April om 11:28 uur.
Laatst gewijzigd op 5 April 2023
om 11:28 uur.
April 5 at 11:28 AM.
Last modified on April 5, 2023
at 11:28 AM.
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Door Ana Tudose

5 April om 11:28 uur.
Laatst gewijzigd op 5 April 2023
om 11:28 uur.
Avatar photo

By Ana Tudose

April 5 at 11:28 AM.
Last modified on April 5, 2023
at 11:28 AM.
Avatar photo

Ana Tudose

The smell was unbearable. 

A blue-green fuzzy growth had made its way out of the bathroom ventilator and was quickly colonising the white ceiling. ‘The mould was in the whole ventilation system of the Sugar Homes. Even though I cleaned it, it would come back immediately. There was nothing I could do’, says international law student Dean.

It wasn’t just an unsanitary situation, but also a very unhealthy one. Dean started feeling ill soon after he moved in. ‘Every three weeks, I would have a cold with coughing and fever. I frequently had to stay at home sick. That probably made it even worse, but I had nowhere else to go’, he says. ‘Finding a place in Groningen is getting harder and harder.’ 

When he finally moved out, he immediately started feeling better. ‘After two weeks, the symptoms had disappeared’, says Dean – who prefers to go by an alias, because he’s taken his landlord to court for refusing to pay back his deposit. 

Serious effect

Dean was lucky to find another place, because mould can have a serious effect on your health, warns the Dutch public health service GGD, especially when you suffer from asthma or other lung problems. It can cause a sore throat, coughing and sneezing, a stuffy nose, or shortness of breath. When you are exposed longer, it can get even worse: you may feel tired, experience headaches, nausea, and fevers. 

The moist Dutch winter climate gives mould every chance to spread, says Sonja Billerbeck, molecular microbiology researcher. ‘Mould is hardy. And they are eukaryotes – cells with a clearly defined nucleus, just like human cells. They are much more closely related to us than to bacteria. That’s why they like a similar environment to humans, with more humidity.’ 

Even though I cleaned it, it would come back immediately

In winter, mould is more prevalent in general. However, unlike in countries such as Spain, where the summers are very warm and dry enough for it to go away, it’s an ongoing problem in the Netherlands, Billerbeck says. 

Add to that old buildings and heating turned low due to the high energy prices, and you can see fungi bloom on window trims and walls, in corners and crevices. ‘Mould especially thrives in houses from the 30s; the conditions are perfect’, says Billerbeck. ‘These houses are made of clay and even paper. The latter, if you break it down, is basically sugar, which becomes a food source for mould. In the presence of water, the spores start multiplying and the mould keeps growing.’ 

She’s not so sure if you can directly link health issues to mould spores, though. ‘This is a very complex topic and I don’t know if there is enough research to analyse that connection. There are a lot of factors that come into play’, she says. Other microbial agents and biotoxins associated with dampness and mould may be the culprit, suggests recent research. ‘Even air pollution can affect the lung conditions that appear in humans.’

Dutch weather

To  international European law student Vaszilia, however, the link between her frequent colds and the mould-infested house she lived in is clear. At first, she thought her stuffy nose and coughing were because of the Dutch weather – it was winter when she moved in – and maybe stress from studying. ‘But it got worse and worse. I even got sick during exam period, which didn’t help’, she says. 

Mould especially thrives in houses from the 30s

Only later, after she had already moved out and stopped having colds so often, did she realise that the mould was probably the reason for her health issues. 

‘Two of my roommates were already living there when I moved in. They were boys, so the apartment wasn’t very clean and it didn’t seem to bother them much. Maybe the mould in the bathroom developed because of that’, she speculates. 


She tried her best to remove it, applying a strong anti-mould solution and ventilating as much as possible. ‘There was no window in the bathroom, so we tried to keep some windows open throughout the apartment.’ 

But it just wasn’t enough. The mould kept coming back. She asked her landlord for help, but he refused. ‘He kept saying that it wasn’t his problem and if we ventilated, it would go away.’

The same happened to Dean. ‘The landlord did not care at all.’

I really do not want to accelerate any immunity flare-ups

But it’s not as simple as that, says a Groningen housing agency employee. ‘Mould is a very common problem in the Netherlands. A lot of people have it or experience it at least once. In most Dutch houses, the insulation is old and especially in winter, the temperature difference can create condensation that makes the mould appear.’

A solution, he says, would be to redo the insulation. ‘But that’s too expensive. It would also mean that the price of the rent would go up and students won’t be able to afford the place anymore.’


Bulent, a Turkish marketing and management exchange student, still hopes his landlord will do something about his mouldy studio. ‘The moment I stepped into the place, I could smell it.’  He started cleaning right away. ‘I have a condition called small intestinal bacterial overgrowth, probably caused by exposure to heavy metals, and I really do not want to accelerate any immunity flare-ups’, he explains. ‘Mould, like heavy metals, can be a trigger.’

He ventilates every day. ‘I even sleep with the window open. But the floor is made of old wood and it’s rotten.’ He contacted his landlord about the situation, but he’s still waiting for someone to come and check. ‘I’ve only reached out to them this week, so I hope they will show up soon.’ 

Bulent hasn’t decided yet what he’ll do if the landlord doesn’t solve the issue.  ‘I think I can manage living here for another few months. Then, I’ll leave and go back to Turkey. Or I might look for another place to rent.’

How to deal with mould

  • Open the windows so humid air can get out. Especially ventilate when you shower or cook!
  • Clean extractor fans, because they can get clogged over time and lose power. 
  • Don’t dry your clothes indoors, or at least open the windows when you do. Without ventilation, the moisture will evaporate from the clothes and settle on the ceiling and walls, contributing to your mould problem. 
  • The greenest option to remove mould is with sodium carbonate (dissolve 6 grams in one litre of water) or neat vinegar. If that doesn’t work, you can use a special mould remover. However, if the circumstances don’t change, it will come back.