Nowadays, numerous building-related diseases are caused by poor indoor air quality. For example, the chemicals of indoor decoration materials will slowly dissipate into indoor environment as time goes on, which will induce a certain degree of health and safety hazards to people who stay indoor for a long time.
For air quality, what comes to most people’s mind first is PM2.5, but the truth is that the excess CO2 in the air is also where the threat comes from.
As we all know, CO2 is nontoxic in terms of gas property. CO2 in the fresh air accounts for about 0.03％. The people who live in it will be free from harm. However, if there are lots of people in this room and the air is not circulated, the oxygen content in the air will relatively decrease and mass CO2 will be produced, at the same time, the people in the room will have different degrees of poisoning symptom.
In the situation that no one is in the room, the content of CO2 normally is 500 to 700PPM. And when it reaches 1% (1000PPM), people will feel the room is stuffy and cannot focus themselves. When it reaches 1500-2000 PPM, people will suffer from asthma, headache and dizziness. The health standard value of CO2 in indoor air is ≤0.10％（2000mg/m3）, namely, ≤1000ppm. In normal conditions, human body is very sensitive to the growth of CO2 in the air. Every 0.5% increase in carbon dioxide content will cause obvious discomfort in the human body.
In the short term being in high concentration of CO2 environment will have no big impacts on our bodies. Nonetheless, if we live and work in the excess CO2 environment, our bodies will be greatly hurt.
Therefore, the indoor CO2 content needs to be constantly monitored to assure the indoor air quality is safe enough. Isweek considers that SH-DS, a CO2 sensor module from South Korea SOHA, can be used for monitoring, which uses infrared principle (dual wave non-dispersive infrared principle (NDIR)) with high humidity resistance. Its data updating is very fast, once per 2 seconds.
In fact, the growth of CO2 content is mainly comes from human activities, also, CO2 is the main factor of greenhouse effect. The volume ratio of CO2 in indoor air is 0.038%, and the mass ratio is 0.058%. At present, since the start of industrialization, the composition of CO2 has increased by about 40%, and the change of air composition is the biggest. Some people think that artificial green house has led to global warming.