Indoor and outdoor air quality investigation at six residential buildings in Hong Kong

The indoor air quality (IAQ) at six residential buildings in Hong Kong was investigated based on different locations and characteristics. IAQ parameters measured from October 1997 to January 1998 included temperature, relative humidity, CO2, PM10, HCHO, bacteria, SO2, NO, NO2, and CO. CO2, PM10, and HCHO were monitored for a 24-h period, and other IAQ pollutants were monitored continuously. IAQ pollutants at the six sites were below the Hong Kong Interim IAQ Guidelines except for PM10 and bacteria levels. Sites where tobacco smoking is permitted had the worst IAQ. During smoking, PM10 levels were as high as 2153 μg/m3. All sites had bacteria levels below the recommended action level of 1000 CFU/m3. Three sites (North Point, Ngau Tau Kok, and Prince Edward), with relatively high bacteria levels, were buildings over 20 y old. Maximum CO2 levels detected were as high as 2.63 mL/L due to poor ventilation. The results indicated that IAQ at residential areas in Hong Kong should be constantly monitored and improved.