Carcinogens in the indoor air of Hong Kong homes: Levels, sources, and ventilation effects on 7 polynuclear aromatic hydrocarbons

The concentration of carcinogens in the airborne dust of 33 homes in Hong Kong was studied to identify the sources and measure the amounts of 7 polynuclear aromatic hydrocarbons (PAH) including benzo(a)pyrene. The 24 hr samples were collected from kitchens and living rooms of working class homes and analyzed by HPLC. The mean levels of PAH in air and dust were comparatively low, with cooking fires and incense associated with significant increases, and window ventilating fans with significant decreases in PAH concentrations. Perceived pollution sources like water heaters, cigarette smoke, and stir‐fry cooking, led to reduced airborne PAH levels because human responses to these emission sources were to increase natural and mechanical ventilation. The data indicated that compensation behaviours can over‐ride the effects of emission sources, and help explain why measures of increased ventilation from open windows and doors were generally associated with higher PAH levels. The results of this study show that indoor air quality in homes varies with cultural practices, behavioural responses, and climate