If black spots and patches have already appeared, Dineley recommends washing the area with a mild solution of multipurpose cleaner. Dineley says he usually uses Swipe. Other options often suggested include bleach and white vinegar, but these leave an unpleasant smell.

“If the walls or ceilings have been very badly affected, and there is damage to the paint or plaster, we would remove any loose or flaking paint, and if necessary remove the defective plaster,” Dineley says.

“After that, we’d apply multi-surface fungicidal wash, then repair surfaces and apply an alkaline-resistant primer (sealer). The next step would be to apply two coats of mould-resistant interior wall finish.

“It is highly recommended to employ the services of a professional decorator to ensure a quality and long-lasting remedy,” Dineley adds.

The stylist

Air is also a good friend to your wardrobe, says Jessica Van De Velde, director of The Changing Room HK, who advises against hanging clothes too tightly to keep mould and odours at bay.

“We recommend buying heat bars, which are available from Wing On department stores. They are easy to install and keep the wardrobe dry all year round.” Fur and leather items should be kept away from the heat source, which will damage them, she adds.

Van De Velde also recommends using charcoal or silica gel sachets as desiccants in drawers and wardrobes. “They do work. Depending on the humidity, they will last from one to three months. You can tell when they need changing because they expand.” She also suggests plastic tubs of desiccants, which have a “full capacity” marker to show when they’re exhausted.

What if you’ve left it too late? “Brushing is effective – for shoes, handbags and clothes: mould or mildew can come away simply with a good brush. Use a toothbrush and rub briskly over the affected area. Then wipe with a very light damp cloth.”

When storing winter clothes and duvets, Van De Velde recommends using Ikea’s fabric storage bags rather than plastic ones, which will sweat with the heat or change in temperatures. Fold the clothes and lay tissue in between them, then insert charcoal or silica gel sachets into the bag before closing, she suggests. Check regularly to replace the sachets and make sure they have not leaked.

“For maximum protection, there are companies that will put your clothes in vacuum-sealed bags, like Jeeves of Belgravia or other good dry cleaning companies,” she says.

The doctor

Mould is also a health issue because the airborne spores can cause allergies, Sai Kung general practitioner Clifford Loo says.

“Illnesses caused by mould allergy can include allergic rhinitis, allergic conjunctivitis, asthma and skin reaction. Asthma attacks in particular are common during the spring among people who are allergic to moulds, causing wheezing, non-stop coughing and rarely hypersensitivity pneumonitis.

“In my clinic, we have recently seen increased cases of itchy eyes, sneezing, hives (urticaria), eczema, coughs and asthma,” he says.

Loo says the rise in humidity also increases the level of environmental pollutants hanging in the air, such as pollen and harmful particulate matter. “Viruses that are already plentiful in this peak season can stay longer in the damp, stagnant air for transmission. So the flu epidemic is still thriving,” he says.

Loo suggests controlling indoor humidity at between 30 per cent and 50 per cent. “It’s best to turn on the dehumidifier in the rooms where you spend most of the time,” he says. “Air purifiers help to eliminate spores, and another tip is to get air conditioners cleaned yearly by the experts.”

Loo also advises wearing a mask outside if it’s foggy to prevent breathing in spores and pollutants. “Don’t run in the fog. You are actually inhaling poison,” he says.