What kind of ventilation is healthy ventilation?

If we wish to ventilate our premises well, we need to ensure cross ventilation, i.e. completely open the window or make a draft for 3-5 min, several times a day. Although this helps let fresh air into the room, it also lets in CO2, bacteria and other dangerous particles from the outdoor air. WHO found that 9 out of 10 people breathe air with a dangerously high concentration of polluted particles (e.g. black carbon) that can penetrate deep into human lungs and cardiovascular systems. WHO further estimates that each year about 7 million people die due to exposure to fine particles in polluted air which leads to diseases such as stroke, heart disease, lung cancer, chronic respiratory diseases and respiratory infections, including pneumonia.

Due to air pollution, ventilating premises by opening windows is no longer healthy. When talking about ventilation systems we need to mention one of their key components, i.e. filters. Air filters constitute an essential element of healthy ventilation – while a heat exchanger reduces heat losses and a fan provides for an adequate supply of fresh air, filters ensure its cleanliness. However, the quality of filters is key, as it decides the size of particles that can be contained by the filter and prevented from reaching the premises and the human body.

All modern ventilation systems are fitted with fresh air filters, although you should also consider the type of filter used. Prior to purchase, it is key to acquire information about the filters used by the selected ventilation system. Filters of lesser quality retain less small particles and vice versa. Available filters include simple filters (e.g. PM10 (G4)) and more complex filters (e.g. PM2.5 (F7)). The latter are capable of retaining even the finest particles that are characterised as carcinogenic (these filters can remove fine air particles which measure 2.5 micrometres or less). Such filters also remove pollen.

Besides having suitable and high-quality filters, healthy ventilation also requires that air circulates along two separate ducts, as this prevents bacteria and germs to enter the premises.