Reducing the carbon footprint of inhalers: Climate and clinical implications

Inhaled therapies are necessary components of treating asthma and chronic obstructive pulmonary disease, but their contribution to greenhouse gas emissions, and hence global warming, is clear. Some use propellants 1300–3350 times more potent as greenhouses gases than carbon dioxide. ⁽²⁵⁾ The gas in a typical salbutamol pressurised metered‑dose inhaler (pMDI) causes about as much global warming as the tailpipe exhaust from a car driven for 300 km. The three main types of inhalers are:

• pMDIs – familiar to GPs as the sort of inhaler in which salbutamol (among many other medicines) is found; used with or without spacers; some are  breath‑actuated
• dry‑powder inhalers (DPIs) – eg Turbuhaler, Accuhaler, Handihaler, Breezhaler, Genuair,

Spiromax and Zonda devices

• soft‑mist inhalers (SMIs) – eg Respimat devices.

For all these device types, the carbon footprint can be calculated throughout the life cycle of the product, including raw materials, production, transport, use and waste disposal. ⁽¹¹⁾ pMDIs rely on the driving force of propellants to atomise droplets containing drugs for deposition in the lungs. All inhalers have some environmental impact in their manufacture, transport, use and disposal, but the hydrofluorocarbon propellants used in pMDIs are such potent greenhouse gases that they are responsible for many times the carbon footprint of the rest of the device. ⁽¹¹⁾ Hence, DPIs and SMIs have much smaller carbon footprints than pMDIs.

pMDIs with spacers are the preferred inhalers for young children (especially below the age of six years) and for people with severely limited inspiratory capacity. For most people, though, switching from a pMDI to a DPI can greatly reduce the carbon footprint without loss of asthma control. ⁽¹²⁾

See AJGP article Respiratory inhalers and the environment and the National Sustainable Asthma Care Roadmap Roundtable Report for further information on prescribing appropriate asthma therapies while considering low carbon options. Page 8 of the roundtable report lists some of the inhaler options available in Australia by class, with estimates of the footprint per inhaler and the PBS restrictions.