CO₂ refers to the concentration of CO₂ present in air, water, or biological systems. CO₂ is a significant greenhouse gas that plays a role in the carbon cycle and influences global climate change. In the context of air or water quality, CO₂ measurement is used to monitor pollution, respiration processes, and the metabolic activity of organisms. CO₂ concentration is also an important indicator in ecological studies, environmental management, and human health, as excessively high levels can negatively affect respiration and ecosystem balance.
