During the past several decades, increasing interest had been shown in the emissions of volatile organic compounds (VOCs) from a variety of materials used indoors. This interest is motivated by the wish to reduce the exposure of humans to toxic substances and, in general, to improve the indoor air quality (IAQ) by the use of less polluting materials. In Hong Kong, the Environmental Protection Department commissioned an indoor air quality investigation collecting data from offices and public places in 1997. The result indicated that many local offices and public buildings had serious problems of indoor air quality. The IAQ Certification Scheme for Offices and Public Places is one of the core elements of the IAQ Management Programme of the HKSAR Government for promoting good IAQ. Office buildings or public places (such as shopping malls, cinemas, restaurants and karaokes) served by mechanical ventilation and air-conditioning (MVAC) systems can be certified in the Scheme. An “Excellent” or “Good” Class IAQ Certificate will be issued to the premises by the competent examiner employed for the certification work if the IAQ of the building or selected locations meets the respective IAQ objectives. The Certificate can be displayed at a prominent location in the premises for public information.