Yes, this is a useful technique for surveying the ventilation in a lot of spaces, although it has some limitations that require careful consideration for your specific application.
Outdoor carbon dioxide (CO2) in our big cities is currently about 450 ppm, and human breath increases this concentration when you’re indoors.
In well ventilated spaces, CO2 should stay below about 800-950 ppm. In poorly ventilated spaces CO2 can reach levels of 3,000-5,000 ppm which is a very dangerous situation ( this can easily happen while driving my car if I don’t take preventative measures).
Surveying CO2 levels in retail, cafes, bars, rideshare, libraries, classrooms and public buildings can be useful to get a general sense of which spaces may have the worst ventilation, and prioritizing actions there.
You can measure CO2 concentration continuously with an affordable wireless indoor air quality monitor. We recommend non-dispersive infrared (NDIR) sensing technology for accuracy and recommend the Aranet4 PRO.
Learn more about protecting ourselves from COVID-19 aerosol transmission from scientists and researchers in this field (updated regularly) – https://tinyurl.com/FAQ-aerosols
- How can airborne transmission of COVD-19 be minimized courtesy of Environmental International
- Control measures for schools courtesy of AIRAH
- Learn more about health and cognitive benefits of good ventilation in the Harvard Study