Open windows 'best option for clean air'

PUBLISHED : Friday, 03 August, 2007, 12:00am
UPDATED : Friday, 03 August, 2007, 12:00am

Natural ventilation is the most effective way to improve indoor air quality, although some new building designs might limit the effect, an indoor-air-quality expert says.

Although air-conditioning might help filter out pollutants, the expert said it had to be used wisely or it could cause more problems.

He was speaking at the release of survey results that showed 65 per cent of respondents believed that keeping windows open could improve indoor air quality significantly, while only 47 per cent thought air conditioners could do so.

The survey, sponsored by Philips and conducted by the Quality Evaluation Centre of City University, polled 500 people last month.

Anthony Law Kwok-yung, an air-quality consultant with more than 10 years' experience, said he generally agreed that keeping windows open was the most effective way to remove and dilute indoor air pollutants.

These pollutants, such as fine particles, formaldehyde, radon or even airborne bacteria, were generally generated by paint, furniture, smoking, pets and cooking.

Dr Law said new building designs usually tended not to favour good ventilation, as many featured non-window type air conditioners that did not allow external air exchanges, while the number and size of windows was minimised.

Chiu Kit-yee, an ear, nose and throat specialist, said indoor air pollutants could cause rhinitis in children and adults, and it was estimated that one in four people in Hong Kong suffered from this.