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10 May 2023

The air quality impact of closing your bedroom door at night

Trying not to suffocate while sleeping

My recent foray into embedded devices has yielded a nice little CO2 sensor based on the Seeed Grove SCD30. I normally place it in the living room and ingest all the data into my Grafana / Prometheus based monitoring system. Unfortunately, looking at some pretty graphs that tell you that you should probably open some windows gets a bit old at times. So I decided to conduct some experiments with the sensor instead.

What follows is highly unscientific (n=1). Proceed with caution.

Most people living with roommates probably have the habit of closing the bedroom door at night. It's also not uncommon to have someone over at night. The same applied for me, only when we moved in together in a new apartment did we start to leave the bedroom door open at night.

The question arises immediately what happens to the CO2 level in each scenario. First, I placed the sensor in the bedroom and left the door open:

01002003004005006007008009001,000↑ co2 (ppm)11 PMApr 1812 AMApr 191 AM2 AM3 AM4 AM5 AM6 AM7 AM8 AM9 AM

As the night progresses we can observe a slight rise in CO2 concentration, but the large body of air in the entire apartment makes sure that the air quality stays in a good range.

Next, I repeated the experiment with the bedroom door closed. Two people, one CO2 sensor, very romantic:

6008001,0001,2001,4001,6001,8002,0002,2002,4002,6002,8003,0003,2003,400↑ co2 (ppm)11 PMApr 1712 AMApr 181 AM2 AM3 AM4 AM5 AM6 AM7 AM8 AM9 AM

I was shocked to see just how high the CO2 concentration goes in a relatively short period of time. Interesting is also the sharp decline once we got up and opened the door.

I'm obviously not qualified to make claims about health impacts, but I wouldn't be surprised if this CO2 level affects sleep quality. For reference, some information on the internet suggests that a concentration starting at 2000 ppm is associated with increased heart rate and headaches.

Needless to say we will leave our door open.