The reason your air con smells, study

It's a popular household item that many couldn’t live without. But a small study out of Hong Kong Baptist University found this appliance could be causing your home to smell.

"One of the most notable indoor air-quality problems is odour emission,” says the study, published in the journal, Indoor Air: The International Journal of Indoor Environment and Health.

The study, led by Lai Ka-man, PhD, associate professor in HKBU’s Department of BiologyBasically, dead skin cells get sucked into the unit, where it is then digested by bacteria. The result leads to the production of ammonium, which can be likened to a urine-like smell, Reader's Digest reports.

While skin shedding is normal, Lai said the occurrence of the smell depends on a couple of factors: the type of filter, the ceiling height, and suction power of the air-conditioner.

"If the suction power is higher, or if you are sitting closer to the ventilator, more likely your skin squames will be drawn into the system," she said.

That said, the researchers did add that a large enough filter should be effective in capturing particles and “help improve the odour problems."

Just make sure you're cleaning it regularly.