Green inhalers: reducing the carbon footprint of asthma care

Purpose of review The respiratory community faces an urgent need to reduce the environmental impact of care as the wider climate crisis threatens to worsen airways disease worldwide. Inhalers contribute a disproportionate share of healthcare emissions because of the hydrofluorocarbon (HFC) propellants in pressurized metered-dose inhalers (pMDIs). We already have effective, low-carbon, per- and polyfluoroalkyl substances (non-PFAS) options; particularly dry-powder inhalers (DPIs). This review summarizes recent developments in propellant technology and evidence on optimizing asthma care to improve outcomes while lowering emissions. Recent findings Life-cycle studies confirm that pMDI emissions are dominated by propellant released during use, whereas DPIs have far lower footprints. New global warming potential (low-GWP) propellants are in advanced development, and the first inhaler using HFO-1234ze(E) has recently been licensed in the UK. Emerging clinical and prescribing data show that optimized therapy, particularly strategies that incorporate low-carbon inhalers, can reduce short-acting beta-agonist (SABA) over-reliance, exacerbations, and per-patient emissions. Guideline-driven, health-system approaches using prescribing data and formulary design can accelerate sustainable, evidence-based inhaler use. Summary The most immediate path to reducing inhaler-related emissions is to optimize asthma care while prioritizing low-carbon devices where appropriate. As low-GWP pMDIs enter the market, careful planning will be needed to ensure reliable, affordable access to pMDIs is maintained or improved globally, particularly in low- and middle-income countries.