London hospital cuts nitrous oxide emissions by 70 per cent with new gas delivery system

A pioneering project at the Royal National ENT and Eastman Dental Hospitals (RNENTEDH) has led to a dramatic reduction in greenhouse gas emissions from dental sedation without any impact on patient care.

The RNENTEDH, which forms part of UCLH, has achieved a landmark reduction in the environmental impact of dental sedation, cutting nitrous oxide (N20) emissions by 70 per cent following the introduction of a new gas delivery system, eAdvantage, by Agile Medical.

Nitrous oxide – commonly known as laughing gas –is widely used in dentistry to help patients feel calm and comfortable during treatment. However, it is also a potent greenhouse gas, with a global warming potential 273 times greater than CO2 over a 100-year period. A single dental sedation appointment can generate the equivalent of up to 94 kg of CO2, roughly the same as driving from London to Edinburgh and back.

Prior to this project, RNENTEDH accounted for 61 per cent of UCLH's total nitrous oxide procurement, using approximately 54,000 litres every year. Nitrous oxide is responsible for around 2.5 per cent of UCLH's entire carbon footprint, meaning even modest reductions can make a meaningful difference.

The NHS has committed to reaching net zero carbon emissions by 2040, with mitigation of anaesthetic gases – including nitrous oxide – identified as a key strategic priority. 

A dedicated team at the RENTEDH – led by paediatric dentistry consultant Alexandra Lyne, sustainability project manager Lyndsay Muirhead, and dental nurse Laxmi Ale-Gurung – assessed three different gas delivery systems to determine whether gas usage could be reduced without compromising patient comfort, procedural outcomes, or the day-to-day workflow of clinical staff.

The eAdvantage system emerged as the clear frontrunner, delivering a 70 per cent reduction in emissions compared with previous practice. The system also includes automated functions that reduce manual tasks, improve safety checks, and streamline monitoring – reducing the likelihood of errors associated with the previous manually controlled equipment.

Ms Lyne said: “This has been a real success for many reasons, and pleasingly just in time for World Climate Day. Patients will continue to receive safe, effective sedation with the added reassurance that their treatment is delivered in a more environmentally responsible way… the system also includes automated functions which reduce manual tasks, enhance safety checks, and streamline monitoring.”

The sustainability exercise built on a research project started at the RENTEDH in October 2022, with follow-up cycles in February, June, and October 2023. It was conducted as a formal quality improvement project and has since been published in the British Dental Journal (January 2026), co-authored by Alexandra Lyne, Sarah Ahmad, and Professor Paul Ashley – all of whom also work with the UCL Eastman Dental Institute.

The study gathered data from 31 dental services across 128 sites in the UK – covering community, hospital, and high street settings – encompassing 891 sedation appointments. It was the first study to quantify the real-world environmental impact of nitrous oxide in UK dentistry across different care settings.

The study found that the average carbon footprint of one week's worth of nitrous oxide sedation in a dental service was over 518 kg of CO2 equivalent. Per patient appointment, the average was 28.62kg CO2e. Wastage was also a significant issue: sites using a central piped gas supply wasted an average of 30 per cent of their nitrous oxide, compared with just 4 per cent at sites using individual cylinders – the approach the Eastman has now switched to.

UCLH is now working closely with UCLPartners, who helped to connect and establish the partnership between UCLH and eAdvantage, to share the learning from this project nationally and have developed a case study to support other NHS trusts in assessing whether these technologies could be adopted in their own dental or sedation services.

John Craig, chief innovation officer at UCLPartners said: “This pilot shows how practical innovation in clinical care can significantly reduce the NHS’s environmental impact while maintaining high-quality patient care. By helping connect clinical teams with new solutions and sharing the learning from projects like this, we can support effective innovations to spread more quickly across the NHS.”

The success of the trial means RNENTEDH will now be able to decommission its central piped nitrous oxide supply and switch to smaller, on-demand gas cylinders – further cutting waste and reducing ongoing maintenance costs.