All of us have already heard about CO2 (Carbon dioxide) as it is a common gas constantly present in our environment.
Although people concerns a lot with CO2 levels, its natural sources are mainly plants (that exhales CO2 at night) and human beings (that exhales it all the time).
The most severe consequences occurs when the activities developed by human beings make this gas increasing in high and dangerous levels lowering the atmosphere capacity to remove it.
Sources indoor are mainly occupants’ presence, combustion and plants.
Threshold: Level higher than 1300ppm indicates that the room should be ventilated.