After a carbon dioxide fire extinguishing system is discharged, what remains in the environment?

The correct answer is that carbon dioxide gas remains in the environment after a carbon dioxide fire extinguishing system is discharged. When a CO2 fire extinguishing system is activated, it releases carbon dioxide, which displaces oxygen in the atmosphere. This is effective for extinguishing fires, particularly in enclosed spaces, as it suffocates the fire by reducing the available oxygen necessary for combustion.

Once discharged, the carbon dioxide will remain in the area until it dissipates into the atmosphere. Therefore, CO2 is the primary substance present immediately after the system operates.

The other gases listed do not remain as a result of the discharge of the extinguishing system. In particular, carbon monoxide is not a product of a CO2 discharge but rather is a toxic byproduct of incomplete combustion in certain fire scenarios. Oxygen is actively displaced during the discharge, and nitrogen, while a major component of air, is not specifically introduced by the CO2 system discharge. Hence, carbon dioxide is the definitive result of using this type of fire suppression system.