building ventilation system

In recent years, population exposure to air pollution has been a major concern. Indoor air quality (IAQ) is mainly monitored with CO2-concentration-based indicators. High levels of CO2-concentration are avoided in buildings when airing by the windows is done and/or when air exchange rate of the existing ventilation is regulated, based on a CO2-level-information. However, as contributing to maintain low CO2-concentration-levels indoors, the increase of outdoor air intake is associated with a more or less important introduction of outdoor air pollutants in the building.