When it comes to air quality, it is easy for everyone to focus on PM2.5, but in fact, excessive carbon dioxide is also an invisible "killer" in the air. For this statement, many consumers may be surprised, isn't carbon dioxide non-toxic? How can it become an invisible gas "killer"?

1. The "internal danger" of carbon dioxide in the air

All this needs to start with carbon dioxide. As we all know, the content of oxygen and carbon dioxide in the atmosphere is relatively stable, with oxygen accounting for 21% and carbon dioxide accounting for 0.03%. Although carbon dioxide itself is not toxic, when the carbon dioxide content in the air exceeds the normal content, it will have an impact on human health.

So why is there too much carbon dioxide and hypoxia? Because when people breathe, they absorb oxygen and exhale carbon dioxide. With more carbon dioxide, the oxygen content in the air will decrease accordingly, and people have become accustomed to the oxygen content in the living environment. When the amount of oxygen absorption is insufficient, it will naturally lead to people's unsuitability, causing people to breathe unsmoothly and other symptoms of hypoxia.

At present, the current indoor air quality standards at home and abroad, without exception, all include carbon dioxide as a key pollutant, and its content has long become an important indicator for evaluating indoor air quality.

2. Don't underestimate hypoxia

Everyone has experienced general hypoxia. Shortness of breath, weakness of limbs, lethargy, lack of concentration, etc. With this reaction, the indoor carbon dioxide concentration has risen to 1000-5000 ppm. Although this concentration range is not life-threatening, it also causes damage to health. Severe hypoxia is even more terrifying. When the carbon dioxide concentration is above 5000ppm for a long time, it will cause brain damage, coma, and even death.

Highly crowded classrooms, crowded conference rooms, bedrooms, and cars are all likely to cause high carbon dioxide concentrations. Take the bedroom as an example. If two people sleep for 8 hours a night, if there is no ventilation, the carbon dioxide concentration can rise to 4000ppm in one night. In a closed classroom, within 60 minutes of class time, the carbon dioxide concentration can reach 3000 ppm, which is twice the current standard of 1500 ppm for primary and secondary schools. In a car with close windows, the carbon dioxide content is often above 3000 ppm and continues to rise.

Don't underestimate this general hypoxia. It is enough to affect the work efficiency of the human brain. Studies have shown that when the carbon dioxide is between 600 ppm and 4800 ppm, the higher the concentration of carbon dioxide in the air, the lower the learning and work efficiency of people, and the higher the error rate of work.

3. How to solve

The concentration of carbon dioxide in outdoor air in cities is usually 400~500ppm. Through indoor air quality standards, we found that in a comfortable and good indoor environment, the concentration of carbon dioxide is better controlled below 600ppm, which is almost the same as the value of outdoor carbon dioxide. Therefore, the main way to solve the problem of hypoxia is to exchange air with outdoor ventilation and introduce fresh air. In the fresh air system, a very important component is the carbon dioxide sensor. The carbon dioxide sensor can monitor the indoor carbon dioxide concentration online in real time, and adjust the opening of the fresh air system and the power supply air volume according to the concentration value.