Infants and young children are more susceptible to the effects of carbon monoxide because their bodies and organs are still developing, and they have a higher metabolic rate. They may also be less able to communicate symptoms.

Faster Metabolism
Children generally have a faster metabolism than adults, meaning they breathe more rapidly and absorb gases more quickly. This increased metabolic rate can lead to a faster uptake of carbon monoxide into the bloodstream, making them more susceptible to the effects of carbon monoxide poisoning.
Higher Respiratory Rate
Children breathe at a faster rate than adults. This higher respiratory rate allows them to take in more air per unit of body weight. If the air contains carbon monoxide, children can inhale larger amounts of the gas in a shorter period, increasing the potential for toxicity.
Smaller Body Size
Due to their smaller body size, children have a smaller blood volume. This means that a given amount of carbon monoxide can cause a higher concentration in their blood compared to adults, leading to a more significant impact on oxygen transport.
Developing Central Nervous System
Children's central nervous systems, including the brain, are still developing. Carbon monoxide can interfere with the delivery of oxygen to developing organs and tissues, potentially causing long-term neurological damage in children.
Higher Oxygen Demand
Children have a higher oxygen demand relative to their body size. The binding of carbon monoxide to haemoglobin reduces the oxygen-carrying capacity of the blood. In children, who already have a higher oxygen demand, this reduction can have more severe consequences.
Limited Ability to Recognise Symptoms
Children may not recognise or be able to communicate the symptoms of carbon monoxide poisoning, such as headaches, dizziness, or nausea. This can delay the identification of exposure and timely medical intervention.
Longer Exposure Periods
In some situations, children may spend more time in enclosed spaces with potential sources of carbon monoxide, such as homes or cars. Longer exposure periods increase the risk of carbon monoxide accumulation and poisoning.
Increased Susceptibility to Hypoxia
Children may be more susceptible to hypoxia, where the body is deprived of adequate oxygen. Carbon monoxide interferes with oxygen transport in the blood, exacerbating the risk of hypoxia in children.