After opening the windows the concentration is balanced with the outdoor one.

Figure 4. The average daily concentrations of SO2


CONCLUSION

The problem building syndrome is significantly related to the total concentration of indoor chemical constituent. Indoor climate problems are more common in building construction environment without mechanical ventilation. It is evident that there is need to increase the outdoor air supply in the indoor of buildings, to minimize the exposure of indoor pollutants that might induce symptoms compatible with sick building syndrome. Furthermore, building materials, building constructions and indoor acitivities should be selected on the principle that the level of indoor air should be of the best quality or the concentration of negative agens should be as low as reasonably achievable. Creative approaches of civil engineers and designers can in the large scale influence indoor air quality.