The ventilation efficiency in a displacement ventilated room with non-buoyant pollutant sources was evaluated under laboratory conditions. The contaminant removal effectiveness was measured for different positions of the pollutant sources and with different ventilation flow rates. The air change efficiency and the temperature gradient in the room was measured for the different ventilation flow rates. The contaminant removal effectiveness was much dependent on the position of the sources and varied from 30 to 240 %.

Nicotine concentration in air has been measured in several restaurants by different measuring techniques. Several problems of the measuring techniques has to be solved before nicotine measurements can be used for approval purposes. For approval purposes, the checking of the ventilation may be more fruitful than nicotine measurements.

Recently, the need to control environmental tobacco smoke {ETS) in restaurants and bars has increased. In Finland, a new law prohibiting ETS states that non-smoking areas must be established and the dispersion of tobacco smoke to non-smoking areas must be prevented. Employees' exposure to ETS must also be limited in restaurants to a reasonable level. In this new situation the existing instructions for designing ventilation in the hospitality industry are inadequate.

The assessment of human exposure to airborne contaminant is an important issue in building design. The physiological significance of such exposure and technical means to minimise such risks have long been known in literatures. (1, 2, 3) In recent years, computational works have increasingly been seen used as design assessment tools as an alternative to site measurement and wind tunnel tests.

Although the REEXS-principle Reinforced Exhaust System) has been the object of numerous investigations, who found substantial improvements compared to ordinary local exhaust ventilation hoods, it is far from being generally accepted and used. A Swiss team consisting of researchers of the ETHZ (Swiss federal institute of technology), the EMPA (Swiss Federal Laboratories for Materials Testing and Research) and the company Sulzer Infra have started a project for further investigations of REEXS hoods in the frame of the COST G3 action Industrial Ventilation.