A label for use by spaces open to the public
Use air-score to indicate how well-ventilated your space is

Creative Commons License
The work related to "Air-Score" is licensed under a Creative Commons Public Domain Mark 1.0 License

The Air-Score label was created by the working group at nousaerons.fr. It's a way for businesses and other places open to the public to let people know how well-ventilated their indoor spaces are.

Download our air-score materials

Air-score labels to print

Air-score sticker for ARANET4 CO2 monitor

Download and print the sticker for the ARANET4 CO2 monitor

French regulations

You can download orignal text and English, Spanish, Italian and Japanese translations of our one-pager summarizing the new French regulations on CO2 levels in schools. Also available: the "air-score" with mention of the thresholds used by French regulations.

Transparent gif images of A to E rates

What is an Air-Score ?

The Air-Score is a label that indicates to visitors to an establishment open to the public what the quality of the indoor air renewal is in an enclosed place. This indicator indicates whether this renewal is excellent, good, average, mediocre or insufficient.

The Air-Score of an enclosed place is determined for nominal use of the place, ie with the planned capacity and without user intervention (such as opening a window). With a score of A or B, we can consider that the renewal is done well; with a score of C, D or E, vigilance and action are required, all the more so if the score is bad. This vigilance can be exercised with a portable CO2 sensor which will measure the effective CO2 level in the room and allow the opening of the windows and/or doors of the room to be modulated in order to promote the renewal of the air (see the website nousaerons.fr ).

The Air-Score is compatible with the opinion of the High Council for Public Health of January 21, 2022: "Notice relating to the measurement of carbon dioxide in the indoor air of establishments open to the public". The Air-Score is determined by the following CO2 levels:

  • CO2 level < 600 ppm : this level is a recommendation of many scientists to fight against COVID-19 and other viruses spreading by aerosols, in catering establishments where wearing a mask is not possible.
  • 600 ppm < Taux CO2 < 800 ppm : this level is a recommendation from the Haut Conseil de Santé Publique and many scientists to fight against COVID-19 and other viruses spreading through aerosols..
  • 800 ppm < Taux CO2 < 1000 ppm : corresponds, in France, to the rate recommended by the Departmental Health Regulations in force in each department.
  • Taux CO2 > 1500 ppm : corresponds to an immediate action threshold, recommended by the High Council for Public Health.
Please note, these thresholds are valid for a CO2 level measured outdoors of approximately 410 ppm which serves as a reference. This rate can reach, in particular during episodes of pollution, up to 500 ppm or even beyond. In these cases, the thresholds to be monitored should be adjusted to the observed increase in the rate outdoors. For example, if the CO2 level measured outdoors is 510 ppm, 100 ppm (= 510 ppm - 410 ppm) must be added to all the thresholds proposed above.

How to measure an Air-Score

The Air-Score is based on measuring the CO2 level in an enclosed area. To determine this, we suggest the following method:

  • Equip yourself with a correctly chosen and calibrated CO2 detector (see the site nousaerons.fr).
  • Measure the CO2 rate for a period representative of the use of the room; for a classroom, it could be a day if the use of the class does not vary during the week with the same conditions and the same number of pupils.
  • Record the maximum CO2 level reached in the room and determine the corresponding "air-score" rate.
  • If, for example, the maximum value is 830 ppm, the room will have an air-score C.
  • Display the air-score corresponding to your measurement at the entrance to the premises to inform users or visitors.

a "Do It Yourself" CO2 Detector

We have designed a "Do It Yourself" CO2 detector displaying the Air-Score of a room. Based upon the very good work of Grégoire Rinolfi, we have modified the design for integrating the "Air-Score".

To make the DIY model, use the files below et the informations available on the website du RINOLFI Detector Design :

Plus d'informations et contacts

The Air-Score is an initiative of the nousaerons.fr working group . For more information on aerosol risk, indoor air quality or CO2 measurement, we invite you to consult our website . You can also contact us on: