The quality of indoor air and its multiple effects on health

The quality of indoor air (QIA) is closely related to the comfort perception of the people occupying them, as we have described in detail in this article on our blog. Beyond the benefit for people's quality of life, QIA also has a close short, medium, and long-term relationship with health. For this reason, it is a fundamental and indispensable factor when assessing the occupancy of a confined space for prolonged use over time.

In modern societies, people spend around 80% of their time indoors such as offices, schools, hospitals, nurseries, shopping centers, private homes... Thus, QIA in these environments has a direct and undeniable relationship with people's health. The World Health Organization estimates that 2 million deaths annually are related to poor indoor air quality, also classifying it as an avoidable risk factor. Furthermore, the relationship of respiratory infections with QIA is beyond question. For example, the presence of moisture or mold due to a lack of adequate ventilation has direct consequences on the appearance of infections (OR: 1.50; CI95%: 1.32-1.70) in both children and adults.

The consequences of poor indoor air quality

According to the National Health and Environment Plan 2022 - 2026, “poor indoor air quality (QIA) causes numerous diseases: respiratory, infectious, allergic, asthma, and even cancer. There are numerous chemical factors as well as physical factors (noise, lighting, thermal comfort, humidity) and biological factors (microbes, viruses, and allergens) that influence the health of building occupants.” The document also states that “in addition to the regulations that regulate some of these factors, the organizations that have focused the most on studying this factor are those related to occupational health as the workplace is one of the places where an adult individual tends to spend the most time, alongside the home, with differences due to gender and age.”

The main factors that determine the quality of indoor air, according to the General Directorate of Health of the European Commission, are the following:

• Radon is naturally present in some regions of Spain and Europe. It can enter buildings and can sometimes cause lung cancer.
• Particulate matter can have harmful effects on health, especially on the respiratory system.
• Microbes, such as mold and viruses, can promote the development of asthma and allergies.
• Domestic animals and pests, such as dust mites, cockroaches, and mice, are important indoor sources of allergens.
• Low humidity causes irritation of the eyes, dryness of the skin and nose, and skin rashes, while high humidity favors the appearance of mold and dust mites.
• One of the main causes of poor indoor air quality is insufficient ventilation, which can affect health and work performance.
• An interior temperature that is too high or too low is unpleasant and can be harmful to health.

Moreover, poor ventilation can lead to high concentrations of carbon monoxide (CO), a colorless, odorless, and tasteless gas. This can cause “a considerable number of acute poisonings and deaths in the general population (with complications and subsequent sequelae). Furthermore, individuals who suffer from CO poisoning are not aware of their exposure since the symptoms are similar to those associated with viral illnesses or clinical depression. In indoor environments, these health risks are associated with the improper use of defective and/or poorly ventilated combustion appliances.” All of the above highlights the need to ensure quality QIA for the health of the entire population.