While you are tired of inhaling polluted air as you throng through the crowded streets, getting a breath of fresh, clean air in your own homes may be just as difficult.

A recent survey conducted by City University of Hong Kong (CityU) reveals that 51 percent of the respondents are not satisfied with indoor air quality.

The people of Hong Kong in general, know what causes poor indoor air quality, said Adelaide Hung, Business Administrative Officer of CityU's Quality Evaluation Centre.

"About 95 percent noted smoking as a detriment to household air quality, while indoor painting and finishing (90 percent) and cooking smell (80.4 percent) were also described as negative factors," Hung said.

However, the sources of indoor air pollutants are more than what meets the eyes and senses. Some of them can come from the solvent used in interior decoration, or even the adhesive used for carpet and linings, he said.

People who live in constantly air-conditioned environment may therefore be exposed to health risks they are unaware of, since there is insufficient fresh air inlet to dilute the air pollutants, said Anthony Law, indoor air quality expert.

"The cooling and warming cycle inside most air-conditioned premises will cause mould and fungi problems," said Law. "Uncleaned air-conditioning system can also be a breeding ground for airborne bacteria and fungi," Law said.

The majority of Hong Kong people seems aware of the importance of natural ventilation, as 92 percent open their windows to improve their indoor air quality. The method, however, is only effective if outdoor air quality is better than indoor one, he said.

"The use of air freshener doesn't kill any germs either. It simply masks the background odour and induces the occupants to breathe in more pollutants," said Law.

(HK Edition 08/03/2007 page6)