Indoor air quality has been studied for decades. It’s been widely shown that air inside buildings is quite different from outdoor air, primarily because of the concentrations of CO2. High levels of CO2 can cause sleepiness, inattentiveness, difficulty solving problems, and in high enough levels can cause unconsciousness. This handy, portable indoor air quality measurement unit gives you an instant snapshot of CO2 levels, temperature, relative humidity, and air pressure.
Since the start of the pandemic, indoor air quality and circulation have been key in tracking and reducing indoor transmission of the virus. While it’s not easy to measure quantities of air for the virus itself, we can do the next best thing and simply measure how much of the air has been breathed by humans. Humans inhale oxygen, nitrogen, etc. and the alveoli in your lungs exchange that oxygen for CO2 in your bloodstream.
So, if we can measure the amount of CO2 in the air, we can get a general feel for how “stuffy” or “used” the air in a room is, which, assuming you have someone who is sick, can also tell you how much virus is likely to be in the air. This can prompt air recirculation systems like HVAC to turn on, or even just get someone to open windows. This can very rapidly reduce the level of CO2 in an area, and make people feel more alert and refreshed, as well as helping reduce levels of transmission. It has also been shown that CO2 levels can affect mood, so fresh air will also keep people happier!
This project uses the SCD40 CO2 sensor from Sensiron, offering +/-(50ppm + 5%) accuracy in measurements. Unfortunately, these sensors are expensive to manufacture, and so a large portion of the cost of this unit goes towards the CO2 sensor alone. However, the benefits of knowing the air quality at your home or office can be huge, so this is a great investment to make. Plus, the unit includes a USB to serial chip, so you can hack on the device and integrate it into your HVAC or other air quality systems!
