What black mould is
- "Black mould" is the everyday name for several dark-coloured mould species on damp gypsum, paint, silicone and fabric. Colour says nothing about toxicity: any indoor mould is a moisture problem.
- It needs a surface that stays wet, or above about 60% relative humidity, for days.
Where it hides in UAE homes
- Around AC supply vents and inside the ducts, where cold metal meets humid room air.
- Behind wardrobes and beds on external walls.
- Bathroom ceilings and silicone joints, especially without an extractor fan.
Health effects
- Spores and fragments are allergens: sneezing, itchy or puffy eyes, coughing and worse asthma, mostly at night in the affected room. The WHO guidelines on indoor dampness and mould (2009) link damp housing to respiratory symptoms.
- Children, people with asthma or allergies and anyone with a weakened immune system are most affected. General information, not medical advice.
When to call a professional
- Patches above about 1 m² (US EPA guidance), mould on gypsum or inside ducts, or mould back within weeks of cleaning.
- Small patches on tiles or sealed paint: detergent, gloves and a mask.
What stops it
- Fix leaks, then hold indoor humidity at 45–55% with a ducted dehumidifier with integrated filtration.
