The concentration levels of particulate matter (PM), airborne fungi, carbon dioxide as well as temperature and relative humidity were investigated in the indoor and outdoor environment of two schools in Athens, Greece during the period January to May 2011. The overall concentration ranges of the indoor measured pollutants were: PM10: 14.92-166.18 μg/m3, PM2.5: 3.16-31.27 μg/m3, PM1: 0.72-9.01 μg/m3, UFP: 4188-63093 pt/cm3, total airborne fungi: 28-2098 CFU/m3 and CO2: 389-1717 ppm.

The importance of reducing adventitious infiltration in order to save energy is highlighted by the relevant building standards of many countries.  This operational infiltration is often inferred via the measurement of the air leakage rate at a pressure differential of 50 Pascals.  Some building codes, such as the UK’s Standard Assessment Procedure, assume a simple relationship between the air leakage rate and mean infiltration rate during the heating season, the so-called leakage-infiltration ratio, which is scaled to account for the physical and environmental properties of a dwelling.  The

Passive stack ventilation is a key feature of sustainable building design and has particular potential for use in tall, multi-storey buildings. However, natural ventilation flows through multiply connected spaces may not behave as expected. Recirculation of air through occupied parts of the building and bidirectional exchange flows at ventilation outlets may compromise the intended ventilation scheme resulting in an uncomfortable indoor environment.