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November 2019

Switching to 'green' inhalers could cut carbon emissions and costs

Switching to inhalers with lower global warming potential could result in significant carbon savings - equivalent to installing wall insulation or cutting meat from our diets, and could also achieved savings for the NHS, researchers claim.

The economic and carbon footprint analysis of NHS prescription data in England reveals that if metered dose inhalers (MDIs) were replaced with the cheapest equivalent dry powder inhaler (DPI), drug costs could be reduced by £8.2m a year.

MDIs contain propellants that are potent greenhouse gases. Although chlorofluorcarbons (CFCs) were banned under the Montreal Protocol in [year], they have been replaced with hydrofluoalkane (HFA) propellants, which are still considered to have significant global warming potential (GWP). Currently, MDIs contribute to an estimated 3.9% of the carbon footprint of the NHS.

For every 10% of HFA MDIs switched to low GWP devices, 58 kt CO2e could be saved each year.

There is a substantial difference in the carbon footprints of MDIs: for example, Ventolin has a carbon footprint of over 25kg CO2e per inhaler, compared with Salamol, with less than 10kg CO2e. DPIs and aqueous mist inhalers do not contain any HFAs.

Authors of the study, published in BMJ Open, say switching to DPis, or small volume HFA MDIs instead of high volume HFA inhalers could achieve substantial carbon savings (Table 1).

They say: 'Patients care about the carbon footprint of their inhalers. Changing on MDI device to a DPI could save 150-400kg CO2e annually, roughly equivalent to installing wall insulation at home, recycling or cutting out meat. These are individual actions that many environmentally concerned individuals are keen to take.'

Responding to the study, Jessica Kirby, Head of Health Advice at Asthma UK, said: 'We recognise the need to protect the environment, but it's critically important that people with asthma receive the medicines they need to stay well and avoid a life-threatening asthma attack.

'Switching to a different type of inhaler can be complicated for people with asthma, as it involves learning a new inhaler technique, so it should only be done with support from a GP or asthma nurse.'

Asthma UK has advised patients: 'It is vital that you keep using your inhalers as prescribed. If you are concerned about the environmental effects, talk to your doctor or asthma nurse at your next annual asthma review, to see whether there is another type of inhaler that would work for you.'


Wilkinson AJK, et al. BMJ Open 2019;9:e028763