Mould: The Health Risk Growing on Your Wall – Daily Trust

Sylvester Ojenagbon

Walk into almost any home after a heavy rain, and you will encounter it somewhere. It could be a dark patch behind the wardrobe, a grey bloom along the bathroom ceiling, or a musty smell that never quite clears. Mould is so ordinary that most people stop noticing it, and that is precisely the problem. What appears to be a cosmetic nuisance is one of the more overlooked public health issues of our time, and it is worsening as cities grow denser and damper.

Now, mould thrives wherever there is moisture, warmth, and something organic to feed on, and in a house, that could be wood, paper, dust or the glue behind wallpaper. It reproduces by releasing spores into the air, and those spores are everywhere, all the time, harmless in small amounts. Problems begin when moisture lets it grow in large colonies. That is when spore counts rise sharply, along with the volatile compounds it releases as it grows.

The health effects are quite common. They are the sort of thing doctors see every week without always tracing them back to a damp wall: coughing, wheezing, a blocked nose, itchy eyes, and skin rashes. For people with asthma, mould exposure can trigger attacks. Children are particularly vulnerable because their lungs are still developing, and research links early exposure to damp, mouldy housing with later childhood asthma. People with weakened immune systems face an additional risk because certain moulds can cause genuine lung infections, rather than just irritation.

The World Health Organization has been blunt about this for years. It finds that occupants of damp or mouldy buildings face up to a 75% greater risk of respiratory symptoms and asthma. It calls for the issue to be considered a public health priority rather than a private inconvenience to sort out alone. Studies from Europe and North America found that between a fifth and a third of homes have damp or mould problems, which are serious enough to be considered a health risk. The true figure is almost certainly higher where record-keeping is patchy.

Bring this down to Africa, and the picture becomes more urgent rather than less. The continent has the ingredients for mould growth in abundance. High humidity across West, Central, and East Africa; a long rainy season in many regions; and a housing stock that often lacks proper damp proofing or ventilation. That does not remove the part each household plays. Climate sets the conditions. However, it is usually daily habits, such as how quickly a leak is reported, whether wet clothes are dried indoors, and whether a window is ever opened, that decide whether those conditions turn into an actual mould problem on a wall.

Nigeria illustrates this well. Lagos alone experiences rainfall of around 1,600 to 1,800 millimetres a year. This arrives in intense bursts that overwhelm drainage. That water seeps into buildings through roofs and walls that were never built to withstand it. In Port Harcourt, Calabar, and parts of the southeast, the humidity barely lets up even outside the rainy season. A large portion of Nigeria’s urban population lives in rented rooms or family compounds. And it is easy, though only partly fair, to blame landlords who are slow to fix a leaking roof. Many residents let small problems linger for too long, painting over a damp patch instead of asking why it is there or waiting for the rains to end, rather than dealing with standing water immediately. Mould becomes something people learn to live with, treated as an inevitability of the climate rather than a hazard a household has real power to prevent.

This calls for attention because Nigeria already carries a heavy burden of respiratory illness. Pneumonia remains one of the leading causes of death in children under five in the country. Mould is far from the only factor at play, but indoor air quality is one of the more modifiable pieces of that puzzle. Unlike outdoor air pollution, which requires a policy change on a scale that takes years, damp and mould in a home can often be eliminated with a roof repair, better ventilation, or properly drying water damage, rather than painting over it.

There is also an economic dimension that receives less attention than it should, and it is one that people feel directly. Mould damages building materials, furniture, clothing, and books. In a household where budgets are already stretched, that is a real financial loss which early attention could have often prevented. Businesses lose stock to mould in poorly ventilated storerooms, and schools lose books the same way. This kind of loss is rarely captured in health statistics, but it is part of the true cost of letting a small damp patch become somebody else’s problem to notice.

What can actually be done starts, above all, with the person living in the house, not the government or the landlord. Most mould problems stay small if someone takes ownership early. Most of this guidance costs little beyond attention and the will to act rather than postpone. Leaks should be fixed as soon as they appear, not once the rains pass, and the damage has spread. Rooms need airflow, which often means making a habit of opening windows rather than relying solely on air conditioning, since that can trap moisture. Bathrooms and kitchens benefit from extractor fans or simply wiping surfaces after use. Clothes should not be left drying indoors. Where mould has already taken hold, thorough cleaning is essential. More importantly, the underlying moisture source needs to be addressed because scrubbing a wall while the leak continues only delays a problem someone will have to face again.

Tenants are not powerless either. Reporting a leak in writing, keeping a record of it, and following up rather than accepting silence puts pressure where it belongs. Waiting quietly for a landlord to notice is itself a choice, and often not the safest one. Stronger building codes are essential, but policy can be slow. A family cannot wait for a new regulation to keep a child’s lungs clear this rainy season. The most reliable protection any household has is its own vigilance: checking corners, rooflines, and window frames regularly rather than waiting for a stain to force the issue.

None of this requires new science. The evidence on mould and health has been building for decades. What it requires, more than anything else, is a change of attitude at the level of the household, a willingness to see a grey patch on a ceiling not as someone else’s job to sort out but as a sign that something needs attention now from the person who lives there.

Ojenagbon, a health communication expert and certified management trainer, lives in Lagos.