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Medical and physiological effects of CO2 exposure: implications for CCUS deployment
25/2/2026
8 min read
Feature
While low ambient concentrations of CO2 are harmless, acute exposure in enclosed environments can lead to symptoms ranging from headache and dizziness to loss of consciousness and death. Understanding these physiological mechanisms is essential for developing safety thresholds and exposure limits that underpin regulatory standards and emergency response planning, with particular implications for carbon capture use and storage (CCUS) development. Charlie Bush reports.
From a medical perspective, CO2 can be dangerous because it affects both the respiratory system and the body’s capacity to deliver oxygen to tissues, explains microbiologist Evelyne Abrazado.
At 0.04%, atmospheric CO2 concentration is currently at its highest point in over 30 million years. As a potent infrared absorber, it plays a central role in global warming. In enclosed or poorly ventilated environments, the same gas can also pose an acute occupational hazard.
At slightly elevated levels, CO2 interferes with normal respiration. Individuals may experience shortness of breath, dizziness or confusion. As concentrations rise, respiratory drive becomes impaired, heart rate can drop and acidosis develops. Above roughly 10%, effects become severe: with loss of consciousness within one minute, seizures and, eventually, death. ‘At very high concentrations, collapse can occur within seconds, often without warning,’ warns Abrazado.