Just as with outdoor air pollution, we can distinguish between short-term effects (which appear on the same day or in the days following exposure) and long-term effects.

Short-term effects of indoor air pollutants

Carbon monoxide poisoning is one of the most concerning short-term effects. In the most severe cases, it can lead to loss of consciousness, neurological or cardiovascular disorders that may result in a coma, or even death.

Other effects, such as allergic reactions (asthma, rhinitis, eye allergies, conjunctivitis) or respiratory symptoms (bronchial hyperreactivity, asthma exacerbation, etc.), have been linked to indoor air pollutants.

Poor air quality has often been linked to the concept of “Sick Building Syndrome,” which emerged in the 1980s. It involves a set of nonspecific symptoms such as fatigue, mucosal irritation (dry throat, dry nose, eye irritation), headaches, respiratory discomfort, nausea, etc., associated with temporary occupancy of spaces such as offices. These observed symptoms are present in indoor environments and generally disappear outside the building.

Sick Building Syndrome appears to stem from numerous factors (physical, biological, chemical, and psychological). Several pollutants (tobacco smoke, formaldehyde, microorganisms, temperature fluctuations, excessively dry air, air conditioning noise, etc.) have been implicated, but to date, it is generally referred to as a nonspecific syndrome.

The Long-Term Effects of Indoor Air Pollutants

Studies on the long-term effects of indoor air pollution are still few in number compared to those available on outdoor air, but this issue has been gaining increasing attention since the 2000s.

Among the most studied conditions are allergic and respiratory diseases. Numerous studies have focused specifically on children’s exposure to tobacco smoke and have clearly demonstrated a harmful effect on asthma, particularly during pregnancy and in the first years of life. More broadly, exposure to chemical and particulate pollution has been linked to the risk of allergic and respiratory diseases (asthma, rhinitis, COPD, etc.). It is also now recognized that the presence of mold can lead to the development of asthma in children.

The role of indoor air pollutants in the worsening or development of cardiovascular diseases and cancers is also well established. Several of these have been classified as carcinogens for humans, including tobacco smoke, asbestos fibers, and radon. The health effects of particulate matter have also been the subject of numerous studies. For other types of disorders (reproductive disorders, neurodegenerative diseases, etc.), their role remains to be confirmed, as the latency period between exposure and the development of the disease makes it difficult to study long-term effects.

Beyond these impacts on the development or worsening of diseases, an increasing number of studies highlight a link between poor air quality and performance, whether among workers or students. The importance of air exchange in these effects has been particularly emphasized.