Carbon monoxide pollution may cause loss of consciousness or death in the exposed individual. For such an event to occur, the likely minimum percentage saturation level of carboxyhaemoglobin in the human blood would be:

Correct option is D

At 60% carboxyhemoglobin saturation, the body experiences extreme hypoxia due to the hemoglobin's inability to carry oxygen effectively. This level is associated with severe symptoms, including deep unconsciousness, seizures, cardiovascular collapse, and often death if the exposure is prolonged.
Carbon monoxide binds to hemoglobin with an affinity approximately 240 times greater than oxygen. At 60% saturation:
· Oxygen delivery to tissues is critically compromised, leading to profound cellular asphyxia.
· Organs such as the brain and heart, which are highly oxygen-dependent, cease to function effectively.
Information Booster: · Why 60% Saturation is Critical:
· At this level, only 40% of the hemoglobin remains available for oxygen transport. This is insufficient for sustaining basic metabolic needs, leading to systemic failure.
· Brain hypoxia manifests as unconsciousness, while myocardial hypoxia can result in arrhythmias or cardiac arrest.
· Symptoms at 60% Carboxyhemoglobin Saturation:
· Rapid loss of consciousness.
· Seizures due to neuronal hypoxia.
· Respiratory failure.
· Death if immediate intervention (such as hyperbaric oxygen therapy) is not provided.