IAQ or Indoor air quality is the air quality within and around buildings and structures. It is not merely a matter of how the environment feels (temperature and humidity), indoor air has a direct impact on our health, comfort and wellbeing. Indoor workplaces are found in many working environments such as libraries, offices, sales spaces, hospitals, schools and kindergartens. At such workplaces, no tasks involving hazardous substances are performed. Nevertheless, occupants may feature symptoms belonging to the sick building syndrome (SBS) such as respiratory diseases (e.g. asthma), allergies, burning of the eyes, scratchy throat, blocked nose, and headaches. In the long term this may even cause lung cancer. These afflictions often cannot be attributed to a single cause, and require a comprehensive analysis besides the testing of the air quality. Poor indoor air quality also causes reduced productivity and impaired learning in schools. Common pollutants of indoor air include air pollutants from indoor combustion (cooking, heating), (second-hand) tobacco smoke, moulds, CO, VOC etc…

The World Health Organization (WHO) and IHME’s Global Burden of Disease study state that globally, about 7 million premature deaths per year are attributed to both indoor and outdoor pollution. Determination of IAQ involves the collection of air samples, monitoring human exposure to pollutants, collection of samples on building surfaces, and computer modelling of air flow inside buildings. Where outdoor air pollution is the subject of long political discussions and differing opinions, indoor air pollution can be tackled quickly.

Source control, filtration, and the use of ventilation to dilute contaminants are the primary methods for improving indoor air quality in most buildings. Modern ventilation systems regulate the indoor air quality based on different parameters, such as temperature, relative humidity, CO₂, CO, LPG and TVOC. These parameters change with the amount of people in the room, their time spent in a room, the outside temperature and the usage of certain pollutants. Together with the increased thermal insulation of our buildings, the importance of intelligent ventilation systems is rising in order to maintain a good indoor air quality and to minimize energy losses.