Air-conditioning can spread germs

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Sun, Mar 01, 2009

The Straits Times

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2BWork/Story/A1Story20090227-124996.html

AsiaOne - Singapore

Air-conditioning can spread germs

By Wong Mei Ling

Many of us in tropical Singapore, with its average humidity of 84 per

cent, swear by the cool comforts of air-conditioning.

However your health can be compromised, especially when an air-

conditioning system (AC system) is not properly maintained.

If, for instance, dust and mould form as a result, symptoms of

allergic rhinitis, an inflammation of the nasal passages, and asthma

can worsen, said Dr Hwang Siew Wai, director of the Bukit Merah

SingHealth Polyclinic.

People who spend a lot of time in air-conditioned office buildings

have more health problems, said a study done in France by Dr Mark

Mendell and published in the International Journal Of Epidemiology in

2004.

These problems include breathing difficulties, skin irritations,

headaches and tiredness.

Dr Mendell said it could be because the ventilation systems in

buildings, especially those with AC systems, spread contaminants into

the air in the room.

Also, wet ceilings and walls, from condensation after the AC system

is switched off, can breed bacteria and mould which are associated

with increased risk of respiratory problems and asthma.

Surfaces in AC systems that remain constantly moist, such as cooling

coils and drip pans, also foster the growth of micro-organisms which

can get picked up in the air supplied to the room.

There is even the possibility of contracting Legionnaires' disease, a

type of pneumonia caused by breathing in the bacteria-laden mist from

the AC's cooling tower.

Even increased obesity has been linked to too much air-

conditioning. 'Air-conditioning is said to decrease the metabolic

rate, therefore causing people to put on more weight,' Dr Hwang said.

However, he cautioned that more research has to be done to establish

a direct link between the two.

Then there is the sick building syndrome. The United States'

Environmental Protection Agency has said that it can arise if the AC

system does not effectively distribute air in the building. This can

lead to symptoms like headaches, irritation in the eyes, nose, or

throat, dry or itchy skin and dizziness.

Elaborating, Dr Chan, senior occupational health physician at

the Office of Safety, Health and Environment, National University of

Singapore, said the chief culprit for such illnesses is poor indoor-

air quality, not how long one has been in an air-conditioned place.

'This is caused by the accumulation of pollutants indoors which are

not adequately removed by the existing ventilation system,' he said.

These pollutants include bacteria, viruses, mould and even dead rats

in the ventilation ducts.

'Carbon dioxide may accumulate too and you may experience some

headaches,' he added. He suggested that windows be opened at the

start of the workday to allow fresh air in. Objects, like old books,

which grow mould should be removed. Drinking lots of fluids helps.

Most importantly, Dr Chan said: 'If you have a contagious disease, do

stay at home or if you really need to be at work, use a face mask to

protect others.'

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This article was first published in Mind Your Body, The Straits Times.