Oxygen (O₂): Definition, formation & consequences

Oxygen: Causes & Origin

Oxygen (O₂) is a colorless and odorless gas that almost all animal life forms require for life. Looking at the mass, oxygen is the most abundant element on the earth's surface. This is because it is present in 21% of the air. However, O₂ occurs chemically bound - i.e. not freely as a breathable gas.

Our oxygen comes primarily from plants. It is the residue of their energy production: photosynthesis. During a biochemical reaction, plants form glucose from sunlight, CO₂ and water, filling up their own energy stores and releasing the oxygen they do not need.

What happens when the body gets too little oxygen?

We need oxygen for our well-being, to be fit and efficient. If the oxygen content drops below 17%, we quickly become tired, and the error rate in visual tasks and logical thinking increases. Reaction time also increases. If the oxygen content of the air we breathe is significantly reduced, symptoms of acute altitude sickness are added: headaches, fatigue, loss of appetite, as well as nausea and dizziness. In severe cases, even brain and lung edema can form.

At oxygen concentrations of less than 13%, severe, non-reversible damage can occur, which can lead to death. Asphyxiation occurs.

What does oxygen saturation mean?

Oxygen saturation indicates the oxygen content in the blood. It is expressed as a percentage of how strongly the hemoglobin, an iron-rich protein in the red blood cells, is loaded with oxygen. In healthy people, oxygen saturation should be between 90 and 99 percent. Lower levels are a sign of an oxygen deficiency, or hypoxemia. This deficiency is noticeable through feelings of weakness, dizziness or malaise.

To boost the functioning of hemoglobin and thus ensure good oxygen saturation, the following foods are suitable:

• Vitamin C-rich food: e.g. oranges, lemons, peppers, tomatoes, grapefruits, berries, watermelon
• Iron-rich foods: e.g. green vegetables, tofu, spinach, eggs, whole grains, legumes, beans, meat, fish, dried fruits
• Folic acid: e.g. beet, green vegetables, sprouts, dried beans, peanuts, bananas, broccoli
• Legumes: e.g. lentils, peanuts, peas, beans

Is oxygen toxic & can you breathe too much oxygen?

Most organisms such as humans, animals and bacteria need oxygen. However, falling below or exceeding the limits can be dangerous. For example, a drop in oxygen saturation in the air threatens fainting - namely from a partial pressure of 0.16 bar. If, on the other hand, the O₂ content in the air is too high, then symptoms of poisoning (oxidosis) occur. Acute oxygen poisoning or oxygen seizure is triggered at an ambient pressure of over 1.6 bar. Divers, for example, are exposed to this risk.

It becomes particularly dangerous if the oxygen saturation in the blood is already high and oxygen is nevertheless added artificially. In this case, the risk of lung failure, heart attacks or cardiac arrhythmias, and organ failure increases.

Symptoms of acute oxidosis are:

• Unrest
• Metal taste on the tongue
• uncontrolled twitching of the facial muscles
• Tunnel vision
• Drowsiness
• Nausea
• Cramps

What is oxygen used for?

We need oxygen primarily for our breathing and for our circulation to function. However, special welding torches can be used to weld and cut metals. In liquid form, oxygen powers rockets. 

What helps against too low O₂ values?

• Ventilate regularly and ensure sufficient fresh air supply.
• Monitor oxygen content especially when heating with fireplace, e.g. with the air-Q & ventilate as needed. Especially when several people are present.
• Place air-purifying plants such as bow hemp, green lily or dragon tree.

We tested how air-purifying plants affect indoor air quality in our air Lab. The results for the indoor plants dragon tree, bow hemp and a test on the effect of plants in general on air components can be found in our separate articles.