Our project would be implemented within the NHS, the most valued service in the United Kingdom. Despite its importance, the NHS is consistently underfunded, leading to reduced service efficacy and forced prioritisation of resources. A critical area the NHS is urgently addressing is its carbon footprint and emissions. Entonox, an anaesthetic gas containing nitrous oxide, contributes significantly to this issue, accounting for 2% of the NHS's total carbon footprint and 75% of its anaesthetic gas emissions - equivalent to 122,880-153,600 tonnes of nitrous oxide released into the atmosphere annually. (note: Calculation done using:
Figure of total carbon footprint from: Office for National Statistics (2024). Measuring UK Greenhouse Gas Emissions - Office for National Statistics. [online] Ons.gov.uk. Available at: https://www.ons.gov.uk/economy/environmentalaccounts/methodologies/measuringukgreenhousegasemissions#:~:text=In%202023%2C%20total%20UK%20territorial [Accessed 22 Sep. 2024].Figure for percentage of total carbon footprint is from healthcare sectors and within that the NHS sector: Mehlmann-Wicks, J. (2023). More support needed to help the NHS reach net zero. [online] The British Medical Association is the trade union and professional body for doctors in the UK. Available at: https://www.bma.org.uk/what-we-do/population-health/protecting-people-from-threats-to-health/more-support-needed-to-help-the-nhs-reach-net-zero#:~:text=The%20health%20service%20contributes%20around.Figure for percentage of carbon footprint that represents nitrous oxide emissions: ‌Evidence-Based Policy Report: Reducing Environmental Emissions attributed to Piped Nitrous Oxide Products within NHS Hospitals. (n.d.). Available at: https://www.publications.scot.nhs.uk/files/piped-nitrous-oxide-products.pdf. )

N2O is not only a potent greenhouse gas but also poses significant public health risks to staff. While safe exposure levels to Entonox in the USA are 25 parts per million, NHS staff have been exposed to levels ranging from 75 to 3,000 parts per million. (note: Mills, G.H., Singh, D., Longan, M., O’Sullivan, J. and Caunt, J.A. (1996). Nitrous oxide exposure on the labour ward. International Journal of Obstetric Anesthesia, 5(3), pp.160–164. doi:https://doi.org/10.1016/s0959-289x(96)80024-0. ) The potential side effects of excessive exposure are: (note: Risks-of-exposure-to-Entonox-to-nursing-and-midwifery-staff.pdf Royal College of Nursing (2021). RCN - Home | Royal College of Nursing. [online] The Royal College of Nursing. Available at: https://www.rcn.org.uk. )

• Decreased mental performance, audio-visual ability, and manual dexterity
• Addiction from repeated administration or exposure to nitrous oxide
• Megaloblastic anaemia and neurological toxic effects (myelopathy) due to inactivation of vitamin B12
• Prolonged exposure may result in bowel distension, middle ear damage, and rupture of ear drums
• Agranulocytosis
• Reduced fertility

Currently, the only other market competitor, Medclair, breaks down nitrous oxide through thermal cracking. While this method is theoretically effective, it is prohibitively expensive, costing upwards of £30,000 for a unit serving just one bed. Additionally, cracking requires high energy levels, generates significant noise, and heats the room, causing discomfort to patients. Medclair also offers a unit for 20 suites costing £350,000, (note: Obtained through verbal discussion with Paul Owen, UK&I National Sales Manager. ) which necessitates extensive infrastructure changes, including pipe installation, taking up to four months to design. Furthermore, gas leakage through pipes is a persistent issue which reduces efficacy.

Our project aims to provide a more affordable, mobile solution for the NHS, redesigning the existing Mobile Destruction Unit to utilise the current infrastructure. This prototype is designed to alleviate some of the NHS's burdens, addressing both environmental impact and staff health.

Our solution aspires to support the NHS, an enduring symbol of public care, by tackling two critical concerns: reducing environmental impact and improving staff health. However, it is important to note that the application of our prototype within the NHS remains theoretical at this stage and will not be implemented for now.

We chose the NHS as our site of application as it is a more local issue in the UK. Alongside the NHS, our system could also be applied in other environments. For example, greenhouses offer an ideal setting for biofilter application, particularly to reduce N2O emissions from the use of nitrogen fertilisers. Globally, there are 496,800 hectares of greenhouse space, with over 8,750 greenhouse vegetable farms in the United States alone. (note: Producegrower.com. (2024). Cuesta Roble releases 2019 global greenhouse statistics. [online] Available at: https://www.producegrower.com/news/cuesta-roble-2019-global-greenhouse-statistics/#:~:text=The%20new%20report%20says%20there [Accessed 24 Sep. 2024]. ) By incorporating a biofilter into ventilation systems, particularly near exhaust fans or passive ventilation areas, future iGEM teams could significantly reduce greenhouse emissions, supporting both organic and conventional farming practices in greenhouses.

In addition, rice paddies significantly contribute to global N2O and CH4 emissions due to nitrogen fertiliser use and irrigation. These conditions promote N2O production through soil and plant processes, making emissions management challenging, where rice farming accounts for 11% of agricultural N2O and 22% of agricultural CH4emissions globally. (note: Qian, H., Zhu, X., Huang, S., Linquist, B., Kuzyakov, Y., Wassmann, R., Minamikawa, K., Martinez-Eixarch, M., Yan, X., Zhou, F., Sander, B.O., Zhang, W., Shang, Z., Zou, J., Zheng, X., Li, G., Liu, Z., Wang, S., Ding, Y. and van Groenigen, K.J. (2023). Greenhouse gas emissions and mitigation in rice agriculture. Nature Reviews Earth & Environment, [online] 4(10), pp.716–732. doi:https://doi.org/10.1038/s43017-023-00482-1. ) This makes rice paddies a potential application area for our iGEM team's biofilter, offering future teams the opportunity to work on mitigating greenhouse gas emissions in this sector.

Furthermore, around 80% of manure is stored as slurry, a mix of water and waste, primarily on larger dairy or swine farms. (note: Teagasc (2020). 2020 - Teagasc Manure Management Report Launched - Teagasc | Agriculture and Food Development Authority. [online] Teagasc.ie. Available at: https://www.teagasc.ie/news--events/news/2020/teagasc-manure-management.php#:~:text=In%20all%2C%2081%25%20of%20manure [Accessed 24 Sep. 2024]. ) The waste is diluted, pumped into a lagoon or tank, and spread on fields as slurry. It can be sprayed on the surface, injected into the soil, or spray irrigated, while solids are separated for conventional spreading. The application of a biofilter could help reduce nitrous oxide emissions from the slurry during storage and field application.

Collaborations and partnerships

Paul Owen: UK&I National Sales Manager for Medclair

In the initial stages of designing our project, we sought insight from Paul Owen, the UK & Ireland National Sales Manager for Medclair. Paul provided a comprehensive overview of the current challenges and the solutions Medclair is implementing to address them. He expressed specific concerns regarding the mobile destruction unit, which we aim to redesign to create a more attractive and effective product for the NHS. His insights were invaluable in helping us understand the market landscape and refine our approach.

Lyndsay Muirhead: Clinical Sustainability Project Manager, University College London Hospital NHS Trust

Our collaboration with Lyndsay Muirhead was instrumental in shaping our project. As a Clinical Sustainability Project Manager within the NHS, Lyndsay provided crucial insights into the current challenges faced by the NHS and highlighted what an ideal solution would entail. Her feedback was integral in refining our design to ensure it addressed real needs without adding to existing problems.

Key contributions from Lyndsay included:

• Identifying the specific need for a product like ours within the NHS
• Providing constructive feedback on multiple design iterations
• Offering context on the NHS's priority areas, emphasising the importance of creating an affordable, effective, and user-friendly solution, even if our project is not the top priority

Lyndsay's guidance ensured that our project remained relevant and aligned with the NHS's goals, helping us develop a solution that could genuinely ease some of the burdens faced by the NHS.