Oxygen: biological information

Oxygen atoms are present in water (H₂O) and water is essential to all life. Oxygen and is present in many organic compounds. Most organisms use oxygen for respiration. While oxygen (O₂) is necessary for life, oxygen as ozone (O₃) is highly toxic. On the other hand, ozone is an important component of the atmosphere (the ozone layer) and helps to shield us from harmful ultraviolet rays from the sun.

Levels in humans

Table: the abundances of the elements in humans.

Human abundance by weight	610000000 ppb by weight
Human abundance by atoms	240000000 atoms relative to C = 1000000

How much oxygen is in your body? Find out here.

You can use this form to calculate how much oxygen your body contains. Enter your weight in either kilograms or pounds and click the "Calculate" button. You must enter a number, not text! Elements for which there are no data will always give a value of zero for the weight, no matter what you put in the weight box.

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Hazards and Risks

Hazards and risks associated with oxygen: oxygen at high partial pressures causes convulsions, pulmonary changes and teratogenic effects. Oxygen as ozone (O₃), peroxide, or superoxide is highly toxic. Too little oxygen results in asphyxiation. Oxygen-enriched air is a fire hazard because the burning rate of combustible materials is increased.