Which gas is known for displacing oxygen in the air?

The gas that is primarily known for displacing oxygen in the air is carbon dioxide. When carbon dioxide concentrations increase, they can replace oxygen in a given volume of air, potentially leading to a hazardous situation where there is insufficient oxygen for respiration.

In environments where carbon dioxide levels rise significantly, such as enclosed spaces or areas with high levels of combustion or biological activity, the oxygen levels can become dangerously low. This is particularly important in fire scenarios or confined spaces where proper ventilation is essential. Carbon dioxide can be a result of combustion processes and can accumulate in such environments, highlighting the need for careful monitoring of gas levels.

Helium, while it is lighter than air and can displace other gases, is not typically associated with health risks related to oxygen displacement. Carbon monoxide, although dangerous due to its toxic nature, primarily binds to hemoglobin in the blood rather than physically displacing oxygen from the air. Nitrogen, while abundant in the atmosphere and theoretically capable of displacing oxygen, is generally inert and does not pose the same health risks that elevated carbon dioxide levels do.