Estimation of carbon emissions from inhaled respiratory medicines in Ireland: a cross-sectional study from a national pharmacy claims database from 2020 to 2022

Abstract

Introduction: Inhaled therapies are essential for managing asthma and chronic obstructive pulmonary disease (COPD), but device choice carries environmental consequences. Inhaler devices influence climate impact; propellant-based metered-dose inhalers (MDIs) have substantially higher carbon footprints than non-propellant inhalers (NPIs). Ireland has committed to net-zero greenhouse gas emissions by 2050, making prescribing practices a relevant focus for mitigation. Aim To describe national dispensing patterns of inhaled respiratory medicines and estimate associated CO₂-equivalent (CO₂e) emissions in Irish primary care, 2020–2022. Method: We analysed Health Service Executive–Primary Care Reimbursement Service (HSE-PCRS) dispensing data for inhaled respiratory medicines (ATC R03) products. Items were classified as MDIs or NPIs. Trends of inhalers use were expressed as year-on-year inhalers dispensed. We conducted scenario analysis in which 10%, 25%, and 50% of 2022 MDIs use were replaced with NPIs to calculate the reduction in carbon emissions. Notably, PCRS schemes cover ~ 43% of the Irish population (predominantly older adults and a lower income group). Results: Between 2020 and 2022, a total of 9.94 million inhalers were dispensed under HSE-PCRS schemes, with annual volumes rising from 3.04 million (2020) to 3.60 million (2022). MDIs increased from 1.50 million (2020) to 1.79 million (2021) and 1.95 million (2022), while NPIs declined − 15.7% in 2021 and then rebounded + 26.8% in 2022. The MDIs share of all inhalers changed from 49.2% (2020) to 57.9% (2021) to 54.2% (2022) for which estimated MDIs carbon emissions were 28.6, 34.6, and 37.6 kt CO₂e, respectively. This emission was accounted for 95–96% of inhaler-related emissions annually. In scenario analyses, replacing 10%, 25%, and 50% of 2022 MDIs use with NPIs resulted in estimated emission reductionof ~ 3.6, 8.9, and 17.9 kt CO₂e, respectively. Conclusion: The results show how MDIs influence the carbon footprint of the health sector and they encourage healthcare providers to support sustainable alternatives. When clinically appropriate, choosing sustainable devices provides significant, short-term CO2 savings without sacrificing treatment.