I/O ratio

Naturally ventilated (NV) buildings, when well designed and operated, can provide adequate indoor environmental quality (IEQ) while reducing the building energy demand. However, in dusty outdoor air, this ventilation technique may increase the penetration of outdoor particulate matter (PM) indoors, leading to adverse health effects. Given the increasing frequency of outdoor dust episodes in Mediterranean climates, an important research question is whether NV buildings can provide adequate indoor air quality (IAQ) during increased outdoor air dust episodes.

According to past researches, most people spend 80%-90% of their time indoors. The ventilation is very important to people’s health and the comfortable surroundings around us. From the viewpoint of energy saving, mechanical ventilation will consume a large amount of additional energy. So variety of ways measuring natural ventilation is worth considering. In fact, in real life, many people tend to have their windows shut rather than open, and the reasons are complex.