We are looking for teachers willing to test Jasper, a CO2 monitor in their classrooms. Jasper is a prototype and we would like to receive user feedback as soon as possible from several countries. If you are interested, please fill out the form: letsair.org/jasper

Jasper monitors the quality of air renewal in this classroom.

This is Jasper, our CO2 monitor, designed for schools, nurseries and anyone who loves penguins and cares about good indoor air renewal.

Achieving good indoor air renewal is possible with a properly sized mechanical ventilation system. An appropriate occupancy rate then allows CO2 levels to be kept very low, thus ensuring excellent comfort and health safety.

For those who are curious, here's what's inside our Jasper prototype. It's simple, inexpensive, and very reliable.

Jasper, our CO2 monitor, is a valuable tool for classrooms and childare. The color of its belly shows the quality of indoor air renewal. Additional technical details are available on the screen at the back. Easy to use, it offers a truly outstanding cost–benefit ratio.

On one side, Jasper, our CO2 monitor, lights up its belly to indicate whether the indoor air renewal of the room is sufficient; on the other side, it gives the measured CO2 level and the corresponding Air-Score.

Photo of the day: Jasper's family, our CO2 monitor, is growing.

Work on Jasper's casing is underway. Jasper is really adorable and very popular, isn't he?

The indoor air quality at the Parisian theater "Studio Marigny" is poor. However, it is still far below the levels recorded in some classrooms where CO2 levels sometimes exceed 3000 ppm. Our CO2 measurements taken at various locations are available at letsair.org#monitoring

To grab attention when the air in a room needs to be renewed, Jasper — our CO₂ monitor — flashes its belly red.

We continue to work on Jasper, our CO2 monitor, to make it simpler and cheaper to produce.

A tiny device is identifying invisible health hazards in Boston schools - @bostonschools.boston.gov is using a nation-leading network of air quality sensors to improve classroom air. www.bostonglobe.com/2025/10/26/s...

Jasper, our CO2 monitor, measures the quality of indoor air renewal. When you press its beak, it announces the measured CO2 level. The green color of its belly indicates excellent renewal. Jasper was created by students from the French engineering school CentraleSupelec.

Here's something that could be hung on the wall of every classroom, hospital, or office: a CO2 monitor that would remind us of what good indoor air renewal can prevent: numerous contaminations. It's reliable and inexpensive to manufacture.

The Mayor of @london.gov.uk has today launched a new £2.7 million programme to deliver air purifiers to hundreds of schools across the capital, bringing cleaner air to tens of thousands of children in their classrooms. A very inspiring initiative with the support of @smartairuk.bsky.social . 👍

letsair.org is a website dedicated to news, infographics, and scientific mediation on indoor air renewal.

Australia's first national report on indoor air quality reveals urgent need for action. It provides the scientific evidence needed to inform policy, regulation and building design to protect people from exposure to harmful pollutants & and airborne pathogens. phys.org/news/2025-10...

A Secret Weapon for Improving Student Outcomes: Better Air Quality. Research shows that test scores and attendance improve when schools install air filters and upgrade ventilation. Thanks to @davidcarel.bsky.social for this reminder. www.the74million.org/article/a-se...

We measured the quality of indoor air renewal in 3 Parisian theaters. On the graph below, we clearly see that their mechanical ventilation systems maintain a maximum CO2 level of : ~900 ppm (@TheatreEdouard7 ) ~1150 ppm (Theatre Montparnasse) ~1300 ppm (@LucernaireParis / Th. noir)

The Parisian theatre "Edouard 7" has a fairly good indoor air renewal, as shown by the measurements below. This allows spectators to comfortably enjoy the show and limits contamination by airborne diseases, especially during a COVID19 peak like the one currently experiencing in France.

Good Air-Score in this classroom. The ventilation works well and the windows are open when necessary. Teaching in a safe and comfortable environment like this should be the norm in all schools.

The new West Lincoln Memorial Hospital was designed during the COVID-19 pandemic, so this was very top-of-mind. Its HVAC system plays a critical role in preventing airborne diseases by controlling how air moves, is filtered and exchanged in the building. www.hamiltonhealthsciences.ca/share/sustai...

In all indoor environmental scenarios, a positive linear relationship was found between the risk of airborne transmission and indoor CO2 levels. The model suggests that the risk of airborne transmission of measles can be easily predicted using a CO2 meter. pubmed.ncbi.nlm.nih.gov/39156354/

Earlier this month, U.S. congressman @reppaultonko.bsky.social (D-NY) and Brian Fitzpatrick (R-PA) reintroduced the Indoor Air Quality and Healthy Schools Act, a bipartisan legislation that aims to protect public health from poor indoor air quality (IAQ). 👍 www.facilitiesnet.com/iaq/tip/New-...

We've released our guide to airborne diseases. Thanks to contributors F.-X. Blanc (Pr of Respiratory Medicine), @ukhadds (Aerosol Scientist), @PascalMorenton (Engineering Professor), L. Vecellio (Aerosol Scientist), and those who do not wish to be named. letsair.org#mediation

"Breathe, it's filtered" "The first offices to offer 3X cleaner air". This is the first time we've seen such a display promoting indoor air quality in buildings. They are located near Paris. We don't know the details of the ventilation system's technical specifications.

Example of infographics showing CO2 measurements from a New York school.

New version of our Air-Score. Your comments are welcome. This a work in progress.

Our air purifier model is on display at the CentraleSupelec French engineering school's fab-lab stand, where it was created with the support of Alexis, its director (pictured), and the entire fab-lab team. Several CO2 monitor models were also prototyped there. Developments continue.

Properly ventilated public buildings are the exception. The United Nations headquarters in New York is not one of these exceptions, nor are the vast majority of schools, hospitals, offices, etc.

In New York state, $50 M will be used to help under-resourced public schools decarbonize their building portfolios. This investment will improve indoor air quality for students and staff and reduce the schools’ carbon footprint. www.governor.ny.gov/news/governo...

On the sidelines of the United Nations General Assembly in New York (September 23, 2025), numerous organizations and two countries came together to sign a global commitment affirming that healthy indoor air is a human right. One of these organizations is "Let's Air."

Inventing aerosols - this article explores A. Trillat’s pioneering research into the airborne transmission of flu & the impact of meteorological factors on epidemics. Trillat [@institutpasteur.bsky.social] was the 1st to demonstrate the airborne transmission of flu. cea.hal.science/cea-05095537v1

A mask to print and stick on the popular ARANET4 CO2 monitor is now available at letsair.org#masks. This helps inform occupants of a premise about the importance of good indoor air renewal to limit the spread of airborne diseases.

Here's something that could be hung on the wall of every classroom, hospital, or office: a CO2 monitor that would remind us of what good indoor air renewal can prevent: numerous contaminations. It's reliable and inexpensive to manufacture.

A second version of our new CO2 monitor, in the hope of sparking the curiosity of occupants and their interest in learning more about indoor air renewal and airborne diseases.

Since a CO2 monitor is also an educational tool, our latest model displays the standard CO2 thresholds used to characterize indoor air renewal and provides a link to learn more about airborne diseases.

A very useful list of interesting and impactful projects related to COVID-19. These initiatives aim to improve air quality, track COVID-related data, and provide valuable resources for individuals and communities. github.com/medero/covid...

French environment code is the most stringent in the world for air renewal in schools. Le code de l'environnement français est le plus exigeant au monde pour le renouvellement de l'air dans les écoles. Download a summary in english at / Retrouvez un résumé en français sur letsair.org#regulations

To estimate the effort required to improve ventilation in this specific theater, we performed a simulation: for adequate air renewal, the theater must double the capacity of its ventilation system. Values ​​without ventilation are given for information. ACH= Air Change per Hour

Australia to lead first-ever United Nations indoor air quality global pledge: the Australian Academy of Science and Burnet Institute are leading global efforts at the United Nations, to declare healthy indoor air a human right. www.nationaltribune.com.au/australia-to...

We measured the CO2 level in a Parisian theater during a performance: the mechanical ventilation, clearly audible elsewhere, maintained 1,300 ppm, which was the regulatory requirement before COVID. The recommendation is now 800 ppm, which will require significant investment.

In an AIRBUS A320 aircraft, cabin air is fully renewed about every 2 or 3 minutes. Part of this "clean air" is indoor air filtered by a HEPA filter, the other part is fresh air coming from outside.

"Invisible and ignored: why indoor air quality deserves our attention. We think a lot about the food we eat and the water we drink, but rarely do we consider the air we breathe, especially when we are indoors where we spend around 90% of our lives." www.phcc.org.nz/briefing/inv...

Below is a poster featuring our Airborne Diseases guide with a direct link to download it. Other layouts or wording are welcome.

We've released our guide to airborne diseases. Thanks to contributors F.-X. Blanc (Pr of Respiratory Medicine), @ukhadds (Aerosol Scientist), @PascalMorenton (Engineering Professor), L. Vecellio (Aerosol Scientist), and those who do not wish to be named. letsair.org#mediation

To raise awareness about airborne diseases, download our 25-page booklet, written with healthcare professionals. It presents the diseases that can be transmitted through the air we breathe, the risks of contamination, and ways to prevent them. letsair.org#mediation

Improved ventilation is associated with lower odds of SARS-CoV-2 infection: the more you ventilate, the more you reduce the risk of contamination. Data from a study of patients exposed to SARS-CoV-2 in shared rooms across five Canadian hospitals: www.cambridge.org/core/journal...

Back to School – What’s in the Air Your Kids are Breathing? by American Lung Association who proposes ressources on this topic at www.lung.org/clean-air/in... The blog : www.lung.org/blog/school-...