Experts blame rushed construction and weak air-conditioning systems for spread of fungi spores that can trigger allergies and asthma.
Complaints of mould in homes 'on increase'
When allergy-causing mould began growing on the airconditioning vents in Rufus Wanjigi's apartment, he received little help from building maintenance.
"Their solution was to set our thermostat at 24°C and wait for the climate to change," he said.
He was told the building in the Dubai Marina area lacked a dehumidifying system, and there was nothing more maintenance could do.
Mr Wanjigi was concerned that the mould would trigger allergies or asthma in his baby daughter, and "her doctor advised us to move out".
According to indoor air quality experts, his complaint is increasingly common in blocks built in recent years.
Rushed construction and poorly designed air-conditioning systems have left many more modern buildings incapable of dealing with the harsh environment, says Steve Ashby, the managing director of Vivoteq Middle East, which uses green technology to improve indoor air quality.
He says the air-conditioning systems in almost nine out of 10 buildings he sees are too feeble to dry the air.
"It can chill the air to 20 degrees, but that air is still really moist," he says. "Temperature won't stop mould from growing."
The most common allergy-causing moulds in the country are Aspergillus and Alternaria, according to Dr Bassam Mahboub, a chest physician and vice chairman of the Emirates Respiratory Society.
Inhaling mould spores can intensify allergies and asthma, affect the upper respiratory tract, cause sinus and staph infections.
The potentially deadly Legionella pneumophila is particularly common in water supplies during summer. It breeds in air-conditioning systems and in water tanks and fittings.
As moulds spread they breed colonies that release spores into the air. Air conditioners need regular maintenance to remove the mould.
According to Barbara Roux, the chief executive of the Dubai-based air-conditioning cleaners Air Environmental Solutions, the lack of regulations on indoor air quality means it can be difficult to persuade property owners to foot the clean-up bills.
After employees repeatedly became sick in a large government building in Sharjah, Air Environmental Solutions performed a study.
It found mould in the false ceilings and air conditioning, along with built-up grease in the restaurant's air ducts. The cleaning bill would have been Dh65,000.
"This poses a severe fire risk, there's a bad microbial report," Ms Roux said. "But they do nothing."
Developers usually contract property management companies to maintain their buildings, but have little control over what is done.
"They only clean what can be seen on the outside," Ms Roux said. "And that is not enough."
Contamination in larger or high-rise buildings is hard to deal with because if mould is found in one unit, the whole building has to be cleaned.
Another problem, according to Ms Roux, is that construction debris often sits inside ceilings long after the buildings are complete. The items left behind become breeding grounds for microbes.
Brennan Berry, who also rents in Dubai Marina, says a musty smell appeared once he turned on the air conditioning during the summer.
He worries that developers cut corners on quality filters and well-built central air conditioning at the cost of his own health.
"It's unskilled labourers and unscrupulous developers," he said. "But I'm the one who gets sick."