Decarbonising Respiratory Care: The Impact of a Low-Carbon Salbutamol Pressurised Metered-Dose Inhalers

Rapid reductions in greenhouse gas (GHG) emissions are vital to combat climate change. Healthcare systems contribute ~5% of global GHG emissions, with pressurised metered-dose inhalers (pMDIs) a significant contributor owing to their hydrofluorocarbon propellants. This study compared GHG emissions of a salbutamol pMDI using a low-carbon propellant in clinical development, hydrofluoroalkane (HFA)-152a, against current salbutamol inhalers.

Three 'cradle-to-grave' lifecycle analyses compared GHG emissions of salbutamol pMDIs with HFA-152a and HFA-134a, and salbutamol dry-powder inhaler (DPI). Over 600 individual emission factors were calculated from > 2000 data points, and categorised into Active Pharmaceutical Ingredients Manufacture, Micronisation, Device, Formulation/Packaging, Use, Distribution and End-of-Life stages. 2023 manufacturing and supply data were collected from Algeria, Australia, Canada, France, Poland, Romania and Saudi Arabia. Carbon footprints were independently verified by the Carbon Trust.

Mean total carbon footprint per salbutamol inhaler (based on 100-year global warming potential [GWP100]) was 26.91, 2.06 and 0.69 kgCO₂e for HFA-134a pMDI, HFA-152a pMDI and DPI, respectively. This equated to a 92% reduction in total emissions for HFA-152a versus HFA-134a. Most pMDI emissions came from the Use stage (HFA-134a: 21.48 kgCO₂e; HFA-152a: 1.45 kgCO₂e). Per actuation, emissions were 135, 10 and 11 gCO₂e, respectively. For each pMDI, GHG emissions were similar across countries.

The low-GWP propellant, HFA-152a is expected to achieve > 90% reduction in the carbon footprint of salbutamol pMDI versus the currently used HFA-134a. The development of salbutamol pMDI with HFA-152a is a crucial step towards ensuring future patient access to salbutamol in a pMDI.