I have a suspicion my home office does has issues with CO2 accumulation when windows/doors are closed, which makes me sleepy.  It is that, or my work is not challenging enough ;-)   

To rule out the latter, I would like to test the indoor air quality for a couple of days.  Has anyone got perhaps an unused CO2 sensor lingering about, or Chinese rip-off of the SCD-40 sensor, that I could use for a couple of days?

Cheers,

Wouter   (Aberdeen)