# Activated carbon filter

An activated carbon filter removes oil vapour, other hydrocarbons and odours from compressed air by adsorption on activated carbon; in Ultra Controlo air treatment, the activated carbon stage of the ULTRAMED unit reduces oil vapour and odours down to 0.003 mg/m³.

In the ULTRAK activated carbon towers, the oil vapours and other hydrocarbons are separated by adsorption as the air passes through a bed of activated carbon; the datasheet requires a coalescing filter upstream and recommends a 1 µm dust filter downstream, and the ULTRAMED unit places a coalescing filter before its activated carbon stage. NHS England's HTM 02-01 (2026) lists a carbon filter among the typical filters of a medical air dryer system, with a water filter or separator, an oil filter, two desiccant dryer columns, a dust filter and a bacteria filter. The 2020 WHO interim specification for PSA plants (superseded by WHO's technical specifications of 31 December 2024) listed a pre-filter, a coalescing filter and a coal filter (coal tower, alternatively an activated carbon filter), as applicable.

The ULTRAK datasheet gives a nominal residual oil vapour content below 0.003 mg/m³ and an ISO 8573-1 quality class for oils of 0/1, and the ULTRAOX 2022 datasheet includes a high efficiency activated carbon filter in the air treatment of ULTRAOX plants. See [what an activated carbon tower does](https://library.ultracontrolo.com/answers/what-does-an-activated-carbon-tower-do/).

## Sources

- [ULTRAMED datasheet, p. 3](https://www.ultracontrolo.com/products/ultramed)
- [ULTRAK datasheet, p. 2](https://www.ultracontrolo.com/products/ultrak)
- [NHS England, HTM 02-01 Part A (2026), paragraph 7.64](https://www.england.nhs.uk/wp-content/uploads/2016/05/health-technical-memorandum-02-01-medical-gas-pipeline-systems-part-a-design-installation-validation-verification-aug-2026.pdf)
- [WHO, Technical specifications for PSA oxygen plants, interim guidance (8 June 2020)](https://www.who.int/publications/i/item/WHO-2019-nCoV-PSA_Specifications-2020.1)
- [ULTRAOX datasheet 2022, p. 16](https://www.ultracontrolo.com/ultraox)
- [WHO, Technical specifications for health facility based medical oxygen systems (31 December 2024), note on the oxygen generator plant specification (supersedes the 2020 interim PSA specifications)](https://iris.who.int/server/api/core/bitstreams/ff437601-add3-44c8-8149-b85f0cdb2b52/content)

Reviewed: 2026-10-22. Ultra Controlo engineering. https://library.ultracontrolo.com/glossary/activated-carbon-filter/