Comparison of concentrations over 24 hours of SO2 and of dark smoke inside and outside a building as a function of its occupation. Comparaison des concentrations de 24h. de SO2 et des fumees noires a l'exterieur et a l'interieur d'un batiment en fonction

Measurements of dark smoke and SO2 concentration made inside and outside a school showed no significant difference in the case of smoke but SO2 concentrations indoors were only 71% of those outside. Holiday periods, when the buildings were unoccupied gave similar results to those periods when thepupils (non-smokers) were present.