Tom Howarth assesses the carbon footprint of asthma inhalers, and what steps can be taken to reduce it.

With an estimated 5.4 million patients suffering from the condition, asthma is one of the most prevalent health problems in the UK and whilst there is no cure for it, many sufferers can lead healthy, active lifestyles thanks to the effective treatment that inhalers provide. However, unbeknown to most patients, and many doctors, inhalers pose a devastating threat to the environment, accounting for almost 4% of the National Health Service’s (NHS) entire annual carbon emissions. If the NHS is to deliver on its ‘Net Zero’ commitments by 2045, then somehow this needs to change — and fast.

The reason behind this astronomically high carbon footprint is that in the UK approximately 70% of inhaler prescriptions are for what’s known as metered dose inhalers, or MDIs. These devices use hydrofluorocarbon (HFC) gases as propellants to ensure the delivery of the medication into the lungs. Whilst this system is extremely efficient, HFCs are powerful greenhouse gases, capable of warming the atmosphere with an effect up to 3800 times greater than CO2.

To put that into context, this means that a typical MDI has a carbon footprint roughly equivalent to driving a car for 180 miles, and since over 50 million of these devices are prescribed in the UK each year, those miles clock up fast.

“A typical MDI has a carbon footprint equivalent to driving a car for 180 miles”

But for those currently sitting at home reading this and cursing their inhalers for poisoning the planet, fear not. There are solutions to the problem.

Firstly, the use of propellant-driven inhalers is not the only option; other devices such as dry-powder inhalers (DPIs) don’t rely on HFCs at all and are consequently much better for the environment. The vast majority of patients can make the switch to these greener inhalers with no detrimental effects on their health, in fact, studies have shown that for the right patient groups DPIs may even be advantageous. As a proof of concept, Sweden has been leading the way on this front for some time, with just 10% of inhalers issued belonging to the MDI category – often they are reserved only for the very young and elderly who cannot generate a large enough inhalation themselves.

To credit the NHS, they do intend to follow suit and have laid out plans to decrease the use of MDIs in their recent report on delivering a ‘Net Zero’ health service. While this is a good start, the plans remain vague, with much of the onus placed on local health care networks to flesh out the details. It’s also important to note that health care leaders have been aware of the environmental impacts of MDIs since at least 2017 (almost certainly much earlier), and yet public awareness of the issue is still dismally low. One study published last year found that 60% of patients would consider switching their MDI inhaler for environmental reasons – meaning we could save 748,000 tonnes of CO2 equivalent per year if people were simply told about the problem.

The other thing worth considering is what happens to these inhalers at the end of their use. At present, just 0.5% are recycled appropriately. The remainder end up in landfill where they not only contribute to plastic waste, but also, eventually, leak any residual propellant into the atmosphere. Unfortunately, the NHS has no national inhaler recycling scheme, and although many local authorities and private enterprises have taken it upon themselves to create one, this does mean being able to recycle your inhaler has become a postcode lottery. Still, it is worth going into your local pharmacy and asking to see whether you’re one of the lucky few.

“At present, just 0.5% of inhalers are recycled appropriately”

One final glimmer of hope is the prospect of environmentally friendly MDIs, which with any luck are just a few years away. By removing HFCs from the equation and replacing them with other, lower-emitting propellants, manufacturers are hoping to give a green option to those patients who are unable to use propellant-free devices, or those who may feel uneasy about making a change to their medical routine. The pharmaceutical giants GSK (for whom 45% of their emissions come from patients using MDIs) and AstraZeneca have already begun testing these next-generation inhalers, with the first rollout anticipated for 2025.

So, if you would like to make a change to your inhaler, then the first thing to do is speak to your GP, they should be informed about other types of devices that would be appropriate for you. In the meantime, the National Institute for Healthcare Excellence has a great decision aid for patients to identify lower-carbon inhalers that can meet their needs and effectively control their symptoms. Finally, make sure that any old inhalers are disposed of correctly and avoid just sending them to landfill — it may require a little effort, but it makes a huge difference in the end.