Why should the indoor air quality be improved

Indoor air quality and ventilation traffic lights in schools

Good air quality in school rooms is a fundamental prerequisite for the concentration and health of teachers and students. An increased carbon dioxide (CO2) - Concentration in the room is associated with an increased concentration of bacteria as well as increased infection and absence rates among students and teachers. CO2 is an odorless gas that is found in the outside air at a concentration of around 400 ppm (parts per million, i.e. CO2 makes up about 400 of 1 million parts by volume of air) is present. CO falls in the body2 as a metabolic product and is exhaled by humans. Its concentration in the exhaled air is around 40,000 ppm. In rooms that are used by many people, for example classrooms, the CO2-Content increase rapidly, depending on:

  • the number of users (class size),
  • the volume of the room,
  • the tightness of the room and
  • the ventilation.

At the same time, numerous other metabolic products that humans give off through the skin and breathing also rise in the room (for example fatty acids, ammonia, volatile organic compounds). CO is used to enrich all of these substances2 as an indicator. In some cases, negative effects were already observed from concentrations of 1000 ppm CO2 observed.

Briefly summarized, studies have shown the following positive effects when the CO2-Concentration was lowered:

  • The subjective well-being was improved.
  • Tests were processed faster and more correctly by students.
  • The noise level in the class dropped.
  • Attention and cooperation have been improved.

That is why the Federal Environment Agency has the following guide values ​​for CO2-Concentration in indoor spaces formulated (here abbreviated):

CO2- concentration

Hygienic assessment


<1000 ppm



1000-2000 ppm


Improve ventilation

> 2000 ppm


Check the ventilation of the room

The health department would like to increase awareness of these interrelationships at schools in the Vogtland district and to improve the quality of the indoor air in the long term in the interests of students and teachers. It is possible to borrow or purchase a so-called VENTILATION TRAFFIC. A ventilation traffic light is a device that shows the current CO2-Measures the concentration in the room. The lights in the colors of a traffic light indicate when fresh air should be supplied to a room. The definition of ventilation regimes and those responsible as well as the involvement of the students bring about fast and lasting results and improvements, taking into account the individual circumstances.

Overall, measures that are easy to implement are intended to help improve the health and performance of children and adolescents.

(As of March 10, 2017)