Indoor air quality at nine shopping malls in Hong Kong

Hong Kong is one of the most attractive shopping paradises in the world. Ma ny local people and international tourists favor to spend their time in sho pping malls in Hong Kong. Good indoor air quality is, therefore, very essen tial to shoppers. In order to characterize the indoor air quality in shoppi ng malls, nine shopping malls in Hong Kong were selected for this study. Th e indoor air pollutants included carbon dioxide (CO2), carbon monoxide (CO) (2) total hydrocarbons (THC), formaldehyde (HCHO), respirable particulate m atter (PM10) and total bacteria count (TBC). More than 40% of the shopping malls had 1-h average CO2 levels above the 1000 ppm of the ASHRAE standard on both weekdays and weekends. Also, they had average weekday PM10 concentr ations that exceeded the Hong Kong Indoor Air Quality Objective (HKIAQO). T he highest indoor PM10 level at a mail was 380 mug/m(3). Of the malls surve yed, 30% had indoor airborne bacteria levels above 1000 cfu/m(3) set by the HKIAQO. The elevated indoor CO2 and bacteria levels could result from high occupancy combined with insufficient ventilation. The increased PM10, leve ls could be probably attributed to illegal smoking inside these establishme nts. In comparison, the shopping malls that contained internal public trans port drop-off areas, where vehicles were parked with idling engines and had major entry doors close to heavy traffic roads had higher CO and PM10, ind oor levels. In addition, the extensive use of cooking stoves without adequa te ventilation inside food courts could increase indoor CO2, CO and PM10 le vels. (C) 2001 Elsevier Science B.V. All rights reserved.