# What purity is PSA oxygen, and is it medical grade?

Single-stage PSA plants such as ULTRAOX produce Oxygen 93, a medical oxygen with its own monographs in the European Pharmacopoeia (Oxygen (93 per cent), 2455) and the US Pharmacopeia (Oxygen 93 Percent).

It contains 90.0% to 96.0% oxygen by volume, the rest mostly argon and nitrogen. ULTRAOX SC and ST plants deliver 94% (±1%) oxygen to European Pharmacopoeia quality; their datasheets give residual contents at initial operation of CO2 below 300 ppm, CO below 5 ppm and a working dew point of −46 °C. Oxygen made by cryogenic distillation, delivered as liquid or in cylinders, follows a different monograph, Oxygen (0417), at 99.5% or more.

## Sources

- [Ultra Controlo, Medical gas answers: EDQM, Ph. Eur. monographs 0417 and 2455; USP, Oxygen 93 Percent; ULTRAOX SC and ST datasheets.](https://www.ultracontrolo.com/medical-gas-answers#what-purity-is-psa-oxygen)
- [European Pharmacopoeia (EDQM)](https://www.edqm.eu/en/newslist/-/asset_publisher/JaJ4OiL8a8pm/content/id/93758)
- [USP-NF, Oxygen 93 Percent](https://doi.usp.org/USPNF/USPNF_M59560_02_01.html)

Reviewed: 2026-10-22. Ultra Controlo engineering. https://library.ultracontrolo.com/answers/what-purity-is-psa-oxygen/