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.

Technology Programme INVENT took place in Finland from 1991 to 1996. In this programme over 100 R&D projects were completed and over 20 Million US dollars used to promote industrial ventilation equipment, systems and services. Based on this, an European COST Action, G3 Industrial ventilation started to further promote this technology. The main aim of the action is to write the "bible" of Industrial Ventilation, DGB, Handbook of Industrial Ventilation. The first part of the book, fundamentals, comes out end of year. The publisher is Academic.