Carbon dioxide has always been regarded as an important greenhouse gas. But in addition to affecting temperature, it can also affect cognitive function. On April 20, 2020, the scientific research team of the University of Colorado (Ball College) published a review article on Geohealth to study indoor carbon dioxide issues.

For a long time, carbon dioxide basically exists in trace amounts in the atmosphere. 800,000 years ago, the carbon dioxide content was only more than 200 ppm. This ppm is a unit name, which means that in every million air molecules, there are several carbon dioxide molecules. This figure has risen a lot since the beginning of industrialization, reaching 280 ppm in 1813 and 409 ppm in 2018.

This is a new situation that mankind has never faced. Previous studies of excessive carbon dioxide only existed in extreme conditions. For example, long-term underwater exposure of strategic submarines led to an increase in carbon dioxide concentration. It was observed that the officers and soldiers on board had anxiety, increased blood pressure, inability to concentrate, and memory loss.

Increasing the indoor carbon dioxide concentration to a certain level will inhibit the excitement of the central nervous system and cause a feeling of drowsiness. Both O2 and CO2 entering the blood are first dissolved, increasing the partial pressure, and then chemically combined. CO2 often plays an important role in respiratory regulation: when arterial blood PCO2 rises within a certain range, it can strengthen the stimulation of breathing; when the human body inhales too much CO2, arterial blood PCO2 exceeds a certain limit, which affects Hb's oxygen carrying and release Oxygen capacity, in severe cases, causes myocardial and whole body hypoxia, central nervous system depression, lethargy, convulsions, and death due to suffocation. Generally, the physiological changes caused are above 1.5% to 3.5%, that is, above 15000 ppm. In this case, CO2 exhibits toxicity. Generally, the outdoor carbon dioxide concentration is 400 ppm, while the indoor concentration can be as high as several thousand ppm. In this case, the impact is mainly mild and long-term, which is this "slightly drowsy" feeling. my country's current standards also recommend that the CO2 concentration be below 1000 ppm. Therefore, if there are conditions, it is necessary to increase ventilation to control the carbon dioxide concentration. In addition, VOC pollution in enclosed spaces cannot be ignored.