Better understand the importance of indoor air renewal in enclosed spaces.

Click on an image below to download a PDF format of an infographic.


This web-site is designed to raise awareness of the importance of good air renewal in enclosed spaces. It brings together information and documents written in English by the "Nous aérons" group, with the help of many people through social networking contacts. We would like to thank all contributors for their kind comments, suggestions and support.



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The infographics and documents provided by letsair.org are licensed under a Creative Commons BY: credit must be given to the creator

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Ventilation matters - Discover why clean indoor air is vital to health


To discover why clean indoor air is vital to health, we recommend the website of National Engineering Policy Centre of United Kingdom. It's a very attractive and interactive site for understanding the basics of ventilation in enclosed spaces : natural or mechanical ventilation, air cleaning, CO2 monitoring... Follow the link below.

Indoor Air Quality Pioneers


By the 19th century, the importance of good air renewal in enclosed spaces was well known. And we even knew how to measure it, thanks to CO2. The limits recommended at the time are similar to those recommended in 2024. All this has been well known for a century and a half.

In the 19th century, school buildings were constructed to comply with hygiene regulations and promote the circulation of fresh air and light. In the 20th century, buildings were progressively constructed more for practical reasons and to be easy to heat, with poor air renewal.

Some theatres, the first in the late 19th century, also developed highly efficient ventilation systems with fresh-air intakes under the audience seats.

CO2 monitoring

Measuring CO2 is a simple, effective and inexpensive way of monitoring the quality of indoor air renewal in enclosed spaces. We propose an easy-to-use ventilation simulator and the "air-score" as an indicator of this indoor air renewal quality.

CO2 monitors Buying Guide

We have selected products that we consider to be «best in class» in several categories. This choice is based on several months' use and on tests carried out on receipt of the equipment. The products we present meet all our requirements. Other products, sometimes less expensive, exist and can perform sufficient functions for certain uses. We have no links of interest with any of the above manufacturers.

Versatile
This versatile model is much appreciated by its users. It is often cited as a benchmark and could be described as the "iPhone" of CO2 monitors.
Connected
This model is perfectly suited to the deployment of a connected monitors fleet in a building. Its LORA connectivity means it's up and running straight out of the box.
Do It Yourself
This model, derived from the "RINOLFI" design, requires only 2 components, 4 wires, 8 solder joints and 2 3D printed parts. The cost is less than 50€.
For children
This is a prototype designed by students. The color indicates the air renewal quality. When the spout is pressed, Jasper announces the CO2 level. It's not commercially available.

Early adopters

Around the world, we can find places where indoor air renewal quality is monitored and CO2 levels displayed. Below, examples. And in Boston, Berkeley, Lübeck and Latvia, CO2 levels of classrooms and social centers can be freely consulted in real time on web dashboards. A remarkable effort of transparency.

Around the world


 
Boston, USA
CO2 monitors in 4322 classrooms


 
Berkeley, California, USA
CO2 monitors in 687 classrooms


 
Lübeck, Germany
CO2 monitors in 2200 classrooms and 28 nurseries


 
Latvia
CO2 monitors in 14000 classrooms / 875 schools and social centers


 
Paris-Saclay Univ. Lending Program


 
US & Canadian libraries Lending Program


 

Metrics and Regulations

what is the correct metric for measuring air renewal in an enclosed space? Here are some answers and some informations or documents related to legal regulations or guidelines related to these metrics and Indoor Air Quality, particularly in schools.. You can also consult Joey Fox's excellent site or this article.

research

Below, an infographic related to an article about masking efficiency, ventilation efficiency and an framework proposal: to study the risk associated with airborne contamination and the means of controlling it, we feel that there is a lack of a large multidisciplinary framework in which all disciplines could express themselves fully.

Do It Yourself

miscellaneous

Contact

This site brings together information and documents written in English by the "Nous aérons" group, with the help of many people through social networking contacts. We would like to thank all contributors for their kind comments, suggestions and support.

This page is maintained by Pascal Morenton, Member of the "Nous aérons" group and expert for a statement of the French High Council for Public Health (Haut Conseil de la santé publique) related to CO2 monitoring. You can contact Pascal at pascal.morenton@letsair.org.