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The provision of greener pressurised metered dose inhalers (pMDIs) for respiratory conditions, such as asthma, could save 619,000 tonnes of carbon emissions in the UK each year, according to a report by the Office of Health Economics (OHE).
The report, published in February 2025 and commissioned by pharmaceutical manufacturer Chiesi, said that a complete switch to using carbon minimal pMDIs could account for up to 10% of the savings in greenhouse gas emissions that the NHS needs to hit its net zero target by 2040.
Carbon minimal pMDIs can reduce carbon emissions by 90% compared with standard pMDIs, by using less harmful propellant gases, the report revealed.
Clinical studies are still ongoing to assess whether carbon minimal pMDIs can form a seamless transition for patients that preserves clinical effectiveness.
In August 2023, The Pharmaceutical Journal reported that the government had taken part in a £33m joint investment with Kindeva Drug Delivery to develop low-carbon propellant greener inhalers.
At the time, the company said it hoped to bring the product to market by 2025 — subject to regulatory approval.
Harriet Lewis, senior director of public affairs and communications at Chiesi UK and Ireland, said to The Pharmaceutical Journal: “Our clinical development will complete by the end of this year. We’re in contact with the Medicines and Healthcare products Regulatory Agency already and will submit as soon as possible, but actual launch will depend on when the regulatory process can be completed, so we are not able to give a specific time.”
The OHE researchers calculated that if all people using standard pMDIs switched to carbon minimal pMDIs, it would save between 415,000 and 619,000 tonnes of carbon emissions annually.
According to the report, the savings associated with a switch to a greener version of pMDIs would make up 7–10% of the total fall in emissions that the NHS needs to achieve its net zero goal.
Currently, there is a focus on cutting carbon emissions from inhalers by switching from standard pMDIs to dry powder inhalers, which do not use greenhouse gases as propellants.
However, the researchers added that dry powder inhalers are not always the best options clinically.
In February 2022, respiratory experts warned The Pharmaceutical Journal that patients in England were having their inhaler devices switched without appropriate consultation, which risked worsening the control of their disease.
In addition, in September 2023, the Scottish government published guidance that did not recommend a “blanket switch” approach to prescribing more environmentally friendly inhalers.
Commenting on the report, Karen Spillett, deputy head of health advice at Asthma + Lung UK, said: “The charity is supportive of lower carbon inhalers being prescribed, as part of the NHS net zero agenda, but never at the expense of someone’s health.
“Well-controlled asthma is the best outcome for your carbon footprint if you have asthma. It is essential that if you have asthma, your inhalers are most suited to you to help protect you from a life-threatening asthma attack. Any inhaler changes should be done carefully and with your input, including a clear demonstration of how to use your inhaler and a check to ensure you’re using it correctly.”
Dave Singh, professor of respiratory pharmacology at the University of Manchester, added: “Carbon minimal pMDIs are an exciting innovation for the NHS, as they provide clinicians and patients currently being treated with pMDIs with the ability to remain on the treatment device that is best for them, while using a formulation that is also significantly less impactful to the environment.”
