Beneath what percentage of oxygen does impairment of motor and mental skills begin?

Impairment of motor and mental skills begins to occur when the oxygen concentration in the air drops below approximately 15 percent. In a normal atmosphere, oxygen levels are around 21 percent. When levels decrease, the body starts to experience a range of cognitive and physical impairments.

Specifically, a drop in oxygen levels begins to impact the brain and nervous system, resulting in reduced coordination, slower reaction times, and impaired judgment. At around 15 percent oxygen concentration, individuals may start to feel symptoms such as shortness of breath, dizziness, and difficulty thinking clearly. This impairment can progressively worsen as oxygen levels continue to decrease.

Understanding the threshold for impairment is crucial in fire investigation and safety protocols, as it highlights the importance of maintaining adequate oxygen levels in environments like burning buildings, where the risk of oxygen depletion can be heightened.