Which gas should be avoided in our air supply due to its hazardous effects?

Carbon monoxide should be avoided in our air supply due to its hazardous effects on the body. It is a colorless, odorless gas that can enter the bloodstream through the lungs and bind to hemoglobin, which significantly reduces the blood's ability to carry oxygen. This can lead to symptoms ranging from headaches and dizziness to more severe consequences, such as unconsciousness and even death in high concentrations.

In the context of diving, the presence of carbon monoxide in breathing gas can be particularly dangerous because it may not be immediately detectable to the diver. It can lead to serious health issues, including carbon monoxide poisoning, which can occur without warning under certain conditions.

Other gases mentioned may have their own risks and considerations in diving scenarios, but carbon monoxide stands out due to its acute toxicity and the specific dangers it poses in an underwater environment where proper oxygenation is critical for survival.