In the study of indoor air quality, the concentration of carbon dioxide (CO2) is an important indicator. Although carbon dioxide is a gas that exists naturally in the atmosphere, its elevated concentration in enclosed or poorly ventilated indoor environments may have negative impacts on human health. Therefore, understanding the safe concentration range of indoor carbon dioxide and identifying possible dangerous levels is essential for maintaining good indoor air quality.

I. Indoor safety concentration of carbon dioxide

Under normal conditions, the CO2 concentration in the atmosphere is about 415 ppm (parts per million). According to the Occupational Safety and Health Administration (OSHA) and other environmental health agencies, the CO2 concentration in indoor environments should be kept below 1000 ppm. At this level, most people do not feel significant discomfort. However, when the CO2 concentration exceeds 1000 ppm, some people may begin to feel a decline in air quality and experience slight discomfort.

II. Impacts of elevated CO2 concentration

1000-2000 ppm: Within this range, people may begin to feel symptoms such as headache, drowsiness, general weakness, and difficulty concentrating. Although these symptoms are usually not severe, they indicate that indoor air quality needs to be improved.

2000-5000 ppm: At this concentration, symptoms may intensify, including increased heart rate, headache, lethargy, and decreased attention and judgment. Long-term exposure to CO2 at this level may have negative impacts on human health.

Above 5000 ppm: This is considered the exposure limit for workplaces by OSHA. At this concentration, severe health problems may occur, such as severe headache, dizziness, confusion, and even coma.

III. Monitoring and controlling indoor CO2 levels

To ensure that the CO2 concentration in indoor air remains at a safe level, the following measures can be taken:

● Use CO2 sensors: By installing CO2 sensors, you can track the carbon dioxide level in indoor air in real-time. When the concentration exceeds the safety threshold, the monitor will issue an alert.

● Improve indoor ventilation: Increasing the circulation of indoor and outdoor air is the most effective way to lower CO2 concentration. Regularly opening windows for ventilation or using ventilation systems can help reduce indoor CO2 accumulation.

● Plant purification: Certain indoor plants have the ability to absorb carbon dioxide and release oxygen, helping to improve indoor air quality.

● Reduce indoor occupancy density: Controlling the flow of people in indoor areas can effectively reduce the production of carbon dioxide.

The concentration of carbon dioxide is an important indicator for measuring indoor air quality. Understanding and monitoring indoor CO2 concentration not only helps protect personal health but is also key to maintaining a comfortable living environment. By taking appropriate measures, such as improving ventilation, using CO2 sensors, and proper indoor layout, you can effectively control indoor carbon dioxide levels and maintain a healthy living and working environment.