Throughout our life we spend more and more time inside buildings (more than 70% of our lifetime). Apart from the time we spend for relaxation, sleep and housework inside our houses we also spend much time for our job, entertainment and other activities inside buildings. The good air quality of an indoor space has a positive influence on people being inside. On the contrary the poor air quality affects not only the health and the mood of the people but also their working effectiveness. Thus, it is important to consider seriously the ventilation of our indoor environment.
An adequate ventilation system according to the needs of the building removes the hazardous gases, whose accumulation can cause various health problems. As an example, the toxic gases which are usually produced in a factory processing chemical substances or in a dye-works must obviously be adequately removed. Nor should the high concentration of CO2 be underestimated in crowded indoor spaces, such as offices, fitness centers, cinema, restaurants, department stores etc. If CO2 by far exceeds the volume percentage of 0.03% compared to the other gases (oxygen, nitrogen, etc.) in an indoor space then it can cause serious health problems concerning headaches, breathlessness, depression, weakness of vision, fainting.