iltmættet

Iltmættet is a Danish term formed from ilt, meaning oxygen, and mættet, meaning saturated. It describes a state in which a substance or environment contains the maximum amount of dissolved oxygen under the prevailing temperature, pressure and salinity. The concept is common in water chemistry, environmental science and physiology, where oxygen availability is important.

In aquatic systems, iltmættet vand denotes water whose dissolved oxygen (DO) concentration equals the saturation level for the given temperature and salinity. Saturation is temperature-dependent: colder water holds more dissolved oxygen than warmer water. DO is typically measured in milligrams per liter (mg/L) or as a percentage of saturation. For example, at about 25 °C in freshwater, air-saturated water is near 100% DO saturation, around 8–9 mg/L; in warmer water, the same DO value corresponds to a lower percentage of saturation.

In physiology, iltmættet blod refers to blood rich in oxygen, usually arterial blood after gas exchange in the lungs, as opposed to iltfattigt blod (deoxygenated blood) found in venous circulation.

Factors affecting iltmætning include temperature, pressure and salinity. Higher temperatures or salinity reduce the solubility of oxygen, lowering saturation; increased pressure tends to raise solubility. The term is primarily used in Danish (and similarly in Norwegian) contexts; in English, it is typically rendered as oxygen-saturated or oxygenated.

See also: oxygen saturation, dissolved oxygen, solubility, Henry's law.