Over the past decade or so, the requirements and standards for indoor air quality have been continuously raised both domestically and internationally. Correspondingly, a series of standards and specifications have been formulated. Especially in recent years, China has formulated and updated relevant standards for indoor heating and ventilation systems as well as indoor air quality.
Carbon dioxide itself is not a toxic gas and does no direct harm to the human body, but it has an impact on human health.
When the concentration of carbon dioxide in indoor air is below 0.7‰, the air is considered clean, and people feel comfortable.
When the concentration ranges from 0.7‰ to 1‰, the air is classified as ordinary, and a few sensitive individuals may detect an odor.
When the concentration is between 1‰ and 1.5‰, the air is at a critical level; other indoor air quality issues start to worsen, and people begin to feel unwell.
A concentration of 1.5‰ to 2‰ indicates mild pollution, while levels exceeding 2‰ signify severe pollution.
At concentrations of 3‰ to 4‰, people experience deepened breathing, accompanied by symptoms such as headaches, tinnitus, and elevated blood pressure.
When the concentration reaches 8‰ or higher, it can cause suffocation and death.
China’s relevant requirements for indoor air quality stipulate that the indoor CO₂ concentration shall always be kept below 1000 ppm, while the normal CO₂ concentration in the atmosphere is around 400 ppm. Maintaining a low CO₂ concentration is important not only because it directly affects people’s working conditions in the environment, but also because it helps improve work efficiency. Meanwhile, it indicates that there is sufficient fresh air in the current environment, which greatly reduces the risk of sick building syndrome. Therefore, CO₂ sensors play a crucial role in the control of heating and ventilation systems. The CO₂ concentration index can also reflect, to a certain extent, the approximate status of other harmful gases in the current environment.
By using CO₂ sensors, the volume of fresh air can be regulated on demand, which complies with green building codes and achieves energy conservation. Therefore, indoor air quality monitoring cannot be separated from the application of high-precision CO₂ sensors.
In addition, the energy-saving operation of heating and ventilation systems is also inseparable from the application of CO₂ sensors. Equipped with CO₂ sensors, heating and ventilation systems can monitor indoor CO₂ concentration in real time, and introduce fresh air from the outdoors in a timely manner based on the current concentration, instead of keeping the fresh air supply running continuously. This avoids unnecessary energy consumption.
