Researches on indoor air quality in Ha Noi as well as in Viet Nam are scarce. Recently, Quang et al. conducted a study on the number concentration of ultrafine particles in indoor and outdoor air in Ha Noi [3]. Occurrence of phthalate diesters in indoor air in northern Viet Nam was investigated by Tran et al. [4]. Tran et al. studied about cyclic and linear siloxanes in indoor air in northern cities in Viet Nam [5]. | Levels of selected indoor air pollutants in three Ha Noi offices
