Indoor and outdoor air quality investigation at 14 public places in Hong Kong

The indoor and outdoor air quality of 14 public places with mechanical ventilation systems in Hong Kong were investigated from October 1996 to March 1997. Fourteen public places located in urban residential, commercial, industrial, and rural areas were selected for indoor/outdoor (I/O) air pollutant measurement. The public places included restaurants, libraries, recreation places, shopping malls, sport centers, and a car park. The concentrations of SO2, CO, CO2, NO, NO2, total hydrocarbons (THC), and particulate matter (PM10) were measured during peak traffic hours at each sampling location. I/O correlations between indoor and outdoor air quality were performed. High I/O ratios of CO, CO2, THC, and PM10 were due to a high infiltration rate and the presence of indoor sources. The results show that the I/O ratios at public places were higher than those at homes and offices. Insufficient ventilation caused high CO2 levels. The I/O ratios of PM10 and CO at public places where tobacco smoking is permitted were 4 times and 1.6 times those where smoking is prohibited. (C) 1999 Elsevier Science Ltd.