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Inhalers and sustainability



You’re seeing a teenager with asthma on the ward round. They are ready to go home after recovering from an asthma attack. You have prescribed them a different preventative steroid inhaler as they’ve had several admissions. Whilst on the ward round, your patient asks if there is any environmental impact with the inhaler as they have heard something about it on social media. Your patient’s parents ask you what they should do with the empty inhaler.

Net zero NHS and the carbon footprint of inhalers

In October 2020, the Delivering a ‘Net Zero’ National Health Service report was published, which reports that the NHS makes up 4% of the UK’s carbon footprint. Surprisingly around 3.1% of the NHS carbon footprint is due to MDIs (metered dose inhalers).

The carbon footprint of propellants in MDIs

The carbon emissions from inhalers result from the propellant rather than the drug itself. The hydrofluorocarbons (HFCs) used in MDIs are potent greenhouse gases. Their effect on climate change is up to 3800 times more potent than carbon dioxide. 70% of the inhalers used in the UK are MDIs, compared to Europe (<50%).

MDIs have a much higher carbon footprint than DPI (dry powder inhalers) – carbon footprints of 500g CO2eq per dose of MDI, compared to 20g per dose of DPI. The website puts this in a more relatable context.

Image adapted from

Equivalent tailpipe greenhouse gas emissions from a Ventolin Evohaler (100 2-puff doses) and a Ventolin Accuhaler (60 1-puff doses). Assumes car achieves 100gCO2/km.

Janson, C., Henderson, R., Löfdahl, M., Hedberg, M., Sharma, R. and Wilkinson, A.J., 2020. Carbon footprint impact of the choice of inhalers for asthma and COPD. Thorax75(1), pp.82-84.

The paper by Janson et al. from Thorax 2020 reports the impact of the different inhaler types on their carbon footprint. Changing from Seretide and Ventolin evohalers to their dry powder equivalent is similar to making the change from a petrol to a hybrid car or switching to a plant-based diet (420kg CO2e/ year)

There are also differences between similar brands. Some reliever MDIs (e.g. Ventolin) use a higher volume of propellant per dose, so their carbon footprint is twice that of other relievers (e.g. Salamol). Some combination LABA / ICS metered dose inhalers, e.g. Flutiform, use a particularly potent hydrofluorocarbon (heptafluropropane HFA227). It creates almost twice the carbon footprint of equivalent combination inhalers using the HFA134a propellant (e.g. Seretide).

But it wouldn’t be safe to change my all my paediatric patients to dry powder inhalers. What else can I do?

The ‘ACT’ proposed by Nooria Azeez and her colleagues in the Pharmaceutical Journal (Best practical principles for inhaler prescribing, August 2022) provides a simple and practical decision-making tool.

  • Assess children’s inspiratory flow using devices like INCHECK- DIAL.
  • Choose the appropriate inhaler device based on their clinical needs, inhaler technique and ease of administration.
  • Train children and families with the use of the new inhaler device and signpost them to resources such as the online inhaler technique videos from the AsthmaUK website

Optimise management of asthma

  • Fewer exacerbations and less use of inhalers
  • Pay special attention to checking inhaler technique
  • The right inhaler for the right child must always be the most important consideration

Prescribe DPIs where appropriate

  • Only when the patient is at an appropriate developmental level and can generate the inspiratory flow to use DPI effectively
  • Generally, for those aged 10-12 years and over
  • Consider ages 6-12 years on a case-by-case basis
  • Some combination DPIs are once-daily dosing, which can also help with adherence

If MDIs are required, use those with the lowest carbon footprint

  • E.g. Ventolin has a carbon footprint twice that of Salamol

Optimise the number of puffs where possible

  • E.g. clenil 100mcg 1 puff rather than clenil 50mcg 2 puffs
  • This also has the advantage that it’s quicker and easier to give to a child 1 puff rather than 2 puffs

Use the NICE decision aid for asthma inhalers and the environment

Environmentally responsible disposal of inhalers

In the West Midlands Severe Asthma multicentre quality improvement project, 83% of parents reported getting rid of their inhalers in a landfill bin. Only 0.5% of inhalers are recycled.

Used MDI inhalers still contain propellants. Household recycling schemes in the UK cannot recycle them. If disposed of in a landfill or household recycling, the residual HFCs in the propellant leak into the atmosphere over time.

There are a small number of recycling schemes. Leicester has the Take AIR scheme (Take Action for Inhaler Recycling), where patients from the Leicestershire area can return their empty or unwanted inhalers through a postal scheme.

If inhalers cannot be recycled locally, they should be returned to a pharmacy where they will be incinerated with the other wasted medicine. This destroys the propellant gases. Collecting used inhalers is currently a quality requirement of community pharmacies in the UK. The website has the most up-to-date recycling information by postcode. If every inhaler user in the UK returned all their inhalers for one year, this could save 512,330 tonnes of CO2eq. This equates to driving a VW Golf around the world 88,606 times.

Direct impact on health from climate change

The Delivering a ‘Net Zero’ NHS report states that the climate emergency is also a health emergency with direct consequences on patients, the public and the NHS. Increases in the intensity of heatwaves, flooding and storms and their associated health problems are already being seen nationally and worldwide. In addition, the predicted changes in the spread of infectious diseases and poor environmental health are expected to impact chronic diseases such as asthma.

Are there any environmental disadvantages to DPIs?

There are concerns that DPIs contain more plastic per inhaler than MDIs. A lifecycle analysis of inhaler types suggested increased freshwater eutrophication (excessive loading of nutrients encouraging algae growth) and fossil depletion for DPIs compared to MDIs but with a lower carbon footprint.

What does this mean for your teenage patient?

You talk with your patient and their family about the different inhaler types and arrange for the respiratory nurse to go through their inhaler technique and choose the best device. You advise the family that their inhaler will be collected with the other medicines waste on the ward for safe disposal. They can take their empty inhalers to their local community pharmacy.


Delivering a ‘Net Zero’ National Health Service. October 2020

Fullwood, I., Evans, T., Davies, B., Ninan, T., Onyon, C., Clarke, J., Srikanthiah, R., Frost, S., Iqbal, N., Atkinson, M. and Rao, S., 2022. Do you know when the inhaler is empty?. Archives of Disease in Childhood.

Janson C, Henderson R, Löfdahl M, et al Carbon footprint impact of the choice of inhalers for asthma and COPD Thorax 2020;75:82-84.

Jeswani, H.K. and Azapagic, A., 2019. Life cycle environmental impacts of inhalers. Journal of Cleaner Production, 237, p.117733

Wilkinson AJK, Braggins R, Steinbach I, et al Costs of switching to low global warming potential inhalers. An economic and carbon footprint analysis of NHS prescription data in England BMJ Open 2019;9:e028763. doi: 10.1136/bmjopen-2018-028763


  • Clare is a Consultant Paediatrician and lead for Respiratory Paediatrics and Cystic Fibrosis in Worcester. She is most proud of setting up the Respiratory and CF MDT in Worcestershire. Her particular interests are cystic fibrosis, bronchiectasis and sustainability. Clare is also a Training Programme Director for the West Midlands School of Paediatrics.

  • Prasad is a Paediatric Respiratory Consultant at Birmingham Children's Hospital, UK and a Senior Clinical Lecturer at the institute of Inflammation and Ageing, University of Birmingham. Pronoun: He/Him



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