Oxygen is the critically most important element for life to sustain on this planet. Anything dependent on fuel power to run actually needs oxygen – be it animals or machines.

The world that we live today is engineered in a manner to consume oxygen in high levels, however, at the same time diminishing and depleting it systematically.  Therefore, the demand-supply imbalance of oxygen has been unavoidable. What has led to the depletion of oxygen production is discussed later in this chapter. The outdoor air in most urban areas today is already oxygen deficient attributed to rapid urbanization, depleting green cover, and increased usage of combustible engines.

Oxygen and IAQ

With increase in indoor-centric lifestyle, buildings today are largely air-sealed and re-circulating the indoor air with no provision of letting in outdoor air. With no inlet of outside air that would be rich in oxygen supply, and increasing number of occupants consuming the already limited amount of oxygen inside, these closed spaces today have become high oxygen deficient zone, and is a catastrophic IAQ crisis. 

As per OSHA (Occupational Safety and Health Association USA), less than 19.5% oxygen levels in ambience is called Oxygen Deficient Environment, which is hazardous for human health. Oxygen levels lower than 21% indoors can trigger immediate effects that could be people feeling breathless, drowsy and restless. Depleting oxygen or O2 levels, mixed with harmful pollutants in the air can cause cancer, respiratory problems, decreased immunity, and lowering energy level.

Table : WHO’s matrix on oxygen levels and its effects