What oxygen concentration does a simple face mask deliver?

A simple face mask typically delivers an oxygen concentration of about 40-60%. This range is achieved because the mask allows some room air to mix with the oxygen from the tank, which results in a variable concentration of oxygen being inhaled by the patient. The exact percentage of oxygen delivered can vary based on the patient's breathing pattern and the fit of the mask.

For example, if a patient breathes more rapidly and deeply, they may receive a lower concentration of oxygen, as they will draw in more ambient air. Conversely, if a patient breathes more slowly and has a good seal on the mask, the delivered concentration might be closer to the higher end of that scale. This makes the simple face mask a useful tool for providing supplemental oxygen in a non-invasive manner while still allowing for variation based on individual circumstances.