There are three ways to produce medical oxygen. Oxygen concentrators are small, portable systems that sit by a patient’s bedside and produce oxygen for one person at a time but can only offer low-pressure oxygen flows of up to 15 liters per minute. Pressure swing adsorption (PSA) plants are very large, complex oxygen generators that require high amounts of electricity and pressure. And air separation units (ASU) produce bulk liquid oxygen, which is stored in large tanks and then vaporized to gaseous medical grade oxygen and fed into a hospital system. Liquid oxygen produced by ASU plants is seen as “best-in-class” and is most commonly used in countries with robust health care facilities.

Overall, liquid oxygen offers higher purity, efficient storage, ease of use and reliability, making it a preferred choice for medical oxygen supply in the treatment of hypoxemia compared to other sources. Liquid oxygen can be stored in large quantities in cryogenic tanks, allowing for a continuous and readily available supply of oxygen. This is particularly beneficial in emergency situations or areas with limited access to oxygen production facilities. Liquid oxygen is more efficient in terms of space and energy consumption. It requires less space for storage compared to other sources (e.g., PSA plants), which often require large compressor systems and multiple adsorption towers. Additionally, medical oxygen can be derived from liquid oxygen without electricity, making it more energy efficient. On a per-unit basis, the production cost of PSA oxygen is 20% higher than that of liquid oxygen. Liquid oxygen is easier to handle and transport compared to oxygen produced by PSA plants. It can be easily transported in portable containers or through pipelines, ensuring a convenient and accessible supply of oxygen to medical facilities.

Liquid oxygen systems are also known for their reliability and durability. They have a long shelf life and can be stored for extended periods without significant loss of quality. This makes liquid oxygen a dependable source of medical oxygen, especially in remote or resource-constrained areas. Liquid oxygen has a higher purity level compared to oxygen produced by PSA plants. Liquid oxygen typically has a purity of around 99.5%, ensuring a consistent and reliable source of high-quality oxygen for medical use.

Building sustainable, reliable and affordable access to medical oxygen and oxygen equipment in low- and middle-income countries is one of Unitaid’s priorities. Through Unitaid’s market-shaping approach, Unitaid works with partners to introduce innovations such as better quality, more affordable oxygen delivery systems; strengthens health security by building regional oxygen production capabilities; creates healthy competitive markets by negotiating lower prices with existing suppliers; and facilitates skills transfer and training for local biomedical workforces and emerging suppliers to meet quality standards. We are also supporting governments and health facilities to determine the most appropriate oxygen system for their needs.

In 2024, for example, we launched a first-of-its-kind regional manufacturing initiative to significantly boost liquid oxygen production across the region, starting with new liquid oxygen production facilities in Mombasa and Nairobi, Kenya. During the COVID-19 pandemic, we delivered emergency oxygen supplies to health facilities in 51 countries; installed, procured or repaired pressure swing adsorption plants; secured unprecedented agreements with two major industrial liquid gas companies, leading to price reductions of 22% for liquid oxygen and 43% for cylinders and cylinder filling; and supported the training of over 17,500 clinical and biomedical staff and the development of national guidelines and training materials in seven countries. Since 2020, we have been co-chairs of two global partnerships of leading health organizations – including the COVID-19 Oxygen Emergency Taskforce and the new Global Oxygen Alliance (GO2AL) – to increase funding for national oxygen systems, expand production and lower the price of oxygen, and provide technical support to governments.