Oxygen from the air is a gas that we must inhale because without it there is no life. Air is a mixture of several different gases including oxygen. Under normal circumstances, 20.9% by volume of oxygen is present in the air. When its concentration falls below 19.5 vol.%, we are talking about the appearance of a oxygen deficiency. Oxygen concentrations below 16 vol.% are considered dangerous to human life.
Oxygen deficiency can occur due to:
- Chemical reactions
- Biological reactions (bacteria, microorganisms)
It is often forgotten that excess oxygen is also dangerous. Elevated oxygen concentrations increase the tendency to ignite gases and materials. Thus, for example, at concentrations above 24% by volume can cause clothing self-ignition. The risk of oxygen oversaturation occurs when bleaching products in the pulp and paper industry or in water treatment plants. Because of that sensors must be certified for use in oxygen-saturated atmospheres.