Carbon Dioxide

Carbon Dioxide (Chemical formula: CO₂） CO₂ is colorless and odorless gas at normal room temperature. It is exhaled by humans and animals, and released in air by burning of fossil fuels and other organic substances. CO₂ is consumed in photosynthesis in trees and green plants. CO₂ is called carbon dioxide gas in a gas form, dry ice in a solid form, and aqueous solution of CO₂ is called soda water or carbonated water. It is used in many fields for industrial applications.

Effects of CO₂ on Health

CO₂ is widely used in fire extinguishers, as a refrigerant (dry ice), and in other applications. CO₂ is not classified as toxic in general. However, caution is required in case of high concentration CO₂ being present in air since there is a risk of carbon dioxide poisoning due to improper usage or handling of CO₂.

CO2 Concentration(ppm)	Health Effects
400	Average outdoor air level
400 - 1,000	Typical level found in occupied spaces with good air echange.
1,000 - 2,000	Level associated with complaints of drowsiness and poor air.
2,000 - 5,000	Level associated with headaches, sleepiness, and stagnant, stale, stuffy air. Poor concentration, loss of attention, increased heart rate and slight nausea may also be present.
5,000	This indicates unusual air conditions where high levels of other gases could also be present. Toxicity or oxygen deprivation could occur. This is the permissible exposure limit for daily workplace exposures.(*)
40,000	This level is immediately harmful due to oxygen deprivation.

* Based on the United States’ Occupational Safety and Health Administration guideline
Source : WISCONSIN DEPARTMENT of HEALTH SERVICES

Impact on Global Warming

It is said that the Global warming is mainly attributed by an increase in greenhouse gases in the atmosphere. Greenhouse gases absorb and retain the heat from the surface of the earth in the atmosphere and return it to the Earth’s surface again (greenhouse effect). Since the Industrial Revolution in the mid of 18th century, the concentration of greenhouse gases in the atmosphere has increased sharply because of fossil fuel use and deforestation.
Among typical greenhouse gases such as CO₂, methane, nitrous oxide, F-gases, etc., CO₂ has the biggest impact on global warming. Its concentration level in the atmosphere has been increasing in recent years.

Reducing CO₂ emissions is a major issue to mitigate global warming and for sustainable social environment and natural environment.

Recent Trends in Japan

【CO₂ level used as an indicator for ventilation】

The Ministry of Health, Labor, and Welfare of Japan recommends that indoor CO₂ concentration should be kept below 1000ppm as a standard for good ventilation. To meet this standard, frequent ventilation is required in densely populated places such as houses, restaurants, or offices.

CO₂ measuring instrument is recommended as an effective way to check whether the ventilation condition meets the requirement or not. From the perspective of measurement accuracy, it is recommended to use a CO₂ measuring instrument with an NDIR type CO₂ sensor integrated.

【Agriculture applications】

The environment inside a closed greenhouse is prone to insufficient CO₂ for growth of vegetables. Since CO₂ is essential for photosynthesis in plants, CO₂ deficiency may cause poor vegetable growth consequently. By controlling the CO₂ concentration in a greenhouse using a carbon dioxide generator, it is expected to improve quality, growth, and yield of crops or vegetables.