Therefore, it is not only essential to monitor the air conditions inside buildings, but also to analyse them and generate indicators to report on environmental quality. This will make it possible to maximise the comfort and health of people inside buildings.
When we talk about air quality, which are the optimal comfort conditions? Why are they considered ideal?
Ideal health and comfort conditions are mainly affected by relative humidity, which should be maintained at between 40% and 70%. Preserving these optimal conditions provides, on the one hand, thermal comfort for people’s convenience and well-being, and on the other hand, health comfort, in which not only it protects the immune system but also affects negatively the transmission of viruses and bacteria, making that space a safer place.
What is thermal and health comfort?
Thermal comfort is based on the transfer of heat between the skin of the human body and the environment, considering metabolism, clothing, etc. These comfort and well-being conditions are defined by temperature and relative humidity ranges that enable people’s comfort as set in various standards, regulations and national and international studies, involving the following ranges:
(*) Depending on whether it is the heating or air-conditioning period of the premises
(**) Under 60% is preferable, although 70% is an acceptable and likely comfort limit in coastal areas.
Environmental temperature and humidity conditions are directly related to health standards. Optimal air quality reduces the spread of infections through a person’s airways.
In fact, relative humidity has been identified as a factor affecting the infectivity and impact of bacteria and virus transmissibility. Airborne viral diseases (such as the influenza virus) are significantly less frequent when relative humidity is above 40%, while their incidence is higher in dry or very dry environments.
Three of the main reasons that define optimal humidity between 40% and 70% values
- In a very dry environment, the human body’s filtering system fails to function at optimal levels because the mucus is reduced and hardened, preventing a correct response from the first immune barrier.
- Environment dryness causes a reduction in the micro-droplets emitted by people’s aerosols (when sneezing or talking, for example). These micro-droplets may carry viruses and bacteria which, as they evaporate more quickly, may remain in the environment longer, making it easier to infect another person.
- The vast majority of viruses and bacteria are highly resistant and have increased viability in low relative humidity conditions.
Temperature and relative humidity conditions of the ambient air inside buildings have a major impact on environmental health and, above all, on the thermal comfort and well-being of people. Monitoring these conditions along with environmental quality indicators makes it possible to know if the environment is suitable, which is crucial both for making decisions on the improvements to be made to the air-conditioning equipment and for making the space safe.