Highlight
– From 2014–2024, 1.6 billion inhalers were dispensed in the US, generating an estimated 24.9 million metric tons of CO2 equivalents (CO2e). Annual emissions rose 24% from 1.9 to 2.3 million mtCO2e.
– Metered‑dose inhalers (MDIs) accounted for 98% of emissions; three agents (albuterol, budesonide‑formoterol, fluticasone propionate) were responsible for 87% of total emissions.
– Estimated social costs of those emissions total $5.7 billion (range $3.5–$10.0 billion). Targeted policy and clinical strategies could substantially reduce future emissions.
Background: Why inhalers matter for health and climate
Respiratory inhalers are essential, often lifesaving, therapies for asthma and chronic obstructive pulmonary disease (COPD). Inhaler devices fall into major types: pressurised metered‑dose inhalers (MDIs) that use hydrofluoroalkane (HFA) propellants, dry powder inhalers (DPIs) that rely on patient inspiratory effort, and soft‑mist inhalers (SMIs) that generate a fine mist without high‑global‑warming‑potential (GWP) propellants. HFAs used in MDIs are potent greenhouse gases; activities that increase MDI use therefore have direct climate consequences.
Against the backdrop of international agreements to reduce hydrofluorocarbons (Kigali Amendment to the Montreal Protocol) and domestic policy interest in decarbonizing healthcare, understanding the magnitude and drivers of inhaler‑related emissions is necessary to design effective mitigation strategies that preserve patient outcomes.
Study design and methods (brief)
The JAMA serial cross‑sectional analysis by Feldman et al. (2025) quantified inhaler dispensing across the US outpatient pharmaceutical market from 2014 to 2024. Authors linked aggregated dispensing data for all inhalers approved for asthma or COPD to previously validated per‑inhaler greenhouse gas emissions estimates (expressed as CO2 equivalents, CO2e). Products were categorized by device type (MDI, DPI, SMI), active ingredient, propellant type, therapeutic class, branded/generic status, manufacturer, payer, and pharmacy benefit manager. Key outcomes were total and annual CO2e, product utilization, and estimated social costs (based on social cost of carbon models reflecting net societal harms from emissions).
Key findings
The primary quantitative results are striking:
– Dispensing volume: 1.6 billion inhalers were dispensed in the US over the 11‑year period (2014–2024).
– Total emissions: Estimated cumulative emissions were 24.9 million metric tons CO2e.
– Trend: Annual inhaler‑related emissions increased by 24%, from 1.9 million mtCO2e in 2014 to 2.3 million mtCO2e in 2024.
– Device contributions: MDIs accounted for 98% of total CO2e despite representing a subset of devices by unit count; DPIs and SMIs contributed minimally to overall emissions because they do not contain high‑GWP propellants.
– Therapeutic concentration: Emissions were concentrated among short‑acting beta‑agonists (SABAs), inhaled corticosteroid–long‑acting beta‑agonist combinations (ICS‑LABA), and inhaled corticosteroids (ICS) classes.
– Leading products: Albuterol (a commonly prescribed SABA), budesonide‑formoterol (an ICS‑formoterol combination), and fluticasone propionate inhalers together accounted for 87% of total inhaler emissions.
– Social cost: Using common social‑cost‑of‑carbon approaches, the authors estimate $5.7 billion in social costs over the study period (lower bound $3.5 billion; upper bound $10.0 billion), representing the monetized harms to society from climate impacts attributable to inhaler emissions.
Clinical and policy implications of the quantitative results
Three features merit emphasis. First, a relatively small number of products and classes drive a disproportionate share of emissions, creating opportunities for focused interventions. Second, rising annual emissions despite climate awareness suggest that prescribing, market forces, and device availability have favored higher‑GWP MDIs. Third, the monetized social costs underscore a nontrivial economic burden tied to inhaler choice that extends beyond direct healthcare expenditure.
Expert commentary and interpretation
Clinical leaders and policymakers should view these results as both a call to action and a cautionary note. There are established clinical pathways to reduce MDI dependence without undermining disease control:
– Encourage use of DPIs or SMIs where clinically appropriate: DPIs and SMIs offer effective drug delivery in many patients and have substantially lower life‑cycle CO2e because they lack high‑GWP propellants.
– Align prescribing with evidence: For asthma, contemporary guideline shifts — notably Global Initiative for Asthma (GINA) recommendations favoring inhaled corticosteroid–formoterol for reliever and maintenance in many patients — can reduce SABA MDI reliance. Adopting ICS‑formoterol strategies may lower the number of SABA rescue inhalers dispensed over time and therefore MDI emissions (GINA report, updated annually).
– Support development and adoption of low‑GWP propellants for MDIs: Industry is developing alternatives (e.g., lower‑GWP HFAs/HFOs, experimental propellants such as HFA‑152a or certain hydrofluoroolefins) that could preserve the clinical advantages of MDIs while sharply reducing climate impact. Regulatory evaluation and robust safety data are essential before wide adoption.
Practical considerations in switching device types
Switching from an MDI to a DPI/SMI is not universally appropriate. DPIs require adequate inspiratory flow and may be less suitable for very young children, some older adults, or patients during severe exacerbations. SMIs can be appropriate alternatives but may have different cost or availability profiles. Any device transition should prioritize shared decision‑making, patient technique training, and outcome monitoring to avoid loss of control or increased exacerbations.
Policy levers and health‑system strategies
Reducing inhaler‑related emissions at scale will require coordinated efforts:
– Formularies and reimbursement: Payers and PBMs can create incentives (e.g., preferred status, lower cost‑sharing) for lower‑GWP inhalers where clinically appropriate, while ensuring access to MDIs for patients who need them.
– Procurement and supply: Health systems and governments can give preferential procurement terms to suppliers of low‑carbon inhalers and purchase devices that meet environmental criteria.
– Education and training: Clinicians and pharmacists should be educated about device options, environmental impacts, and switching protocols. Patient inhaler technique programs and inhaler stewardship—analogous to antimicrobial stewardship—can optimize both clinical outcomes and environmental footprint.
– Innovation support: Regulatory agencies and funders can accelerate evaluation of low‑GWP propellants and novel devices, including funding life‑cycle assessments, clinical comparability studies, and safety surveillance.
Limitations and uncertainties
Feldman et al. used aggregated dispensing data and per‑inhaler emission estimates derived from prior life‑cycle analyses. As a result, the analysis does not capture device manufacturing differences that vary by manufacturer, regional supply chain nuances, or patient‑level variations in use (e.g., number of actuations wasted, priming, improper technique). The social cost estimates depend on assumptions about the social cost of carbon, which are inherently model‑dependent and variable across jurisdictions. The study focused on outpatient dispensing in the US and did not include inpatient use, exports, or international manufacturing emissions attributable to US demand. Despite these limitations, the magnitude and trend identified are robust enough to justify targeted mitigation efforts.
Gaps and research priorities
Key areas for future work include:
– High‑resolution life‑cycle assessments comparing current MDIs, DPIs, SMIs, and emerging low‑GWP MDIs across manufacturers.
– Pragmatic trials and implementation studies evaluating clinical and environmental outcomes of systematic device switching, including effects on exacerbation rates, adherence, and patient satisfaction.
– Economic analyses combining healthcare costs, patient costs, and social cost of carbon to guide payer policy.
– Safety and efficacy evaluation of new low‑GWP propellants in inhaler devices, with transparent postmarketing surveillance.
Conclusions
The JAMA analysis provides a timely, quantitative appraisal of the climate impact of inhaler prescribing in the US: 1.6 billion devices dispensed between 2014 and 2024 generated approximately 24.9 million mtCO2e and $5.7 billion in estimated social costs, with most emissions attributable to MDIs and a small set of products. Achieving meaningful reductions in inhaler‑related greenhouse gas emissions is feasible through a combination of clinical practice changes (appropriate shift to DPIs/SMIs, guideline‑concordant use of ICS‑formoterol), payer and procurement policies, and the development and uptake of low‑GWP propellants. Any strategy must center patient safety and equity, ensuring that device changes do not compromise disease control, access, or affordability.
Funding and trial registration
Primary study reference (do not alter): Feldman WB, Han J, Raymakers AJN, Furie GL, Chesebro BB. Inhaler-Related Greenhouse Gas Emissions in the US: A Serial Cross-Sectional Analysis. JAMA. 2025 Nov 11;334(18):1638-1649. doi: 10.1001/jama.2025.16524. PMID: 41051742; PMCID: PMC12501860.
Selected references
1) Feldman WB, Han J, Raymakers AJN, Furie GL, Chesebro BB. Inhaler-Related Greenhouse Gas Emissions in the US: A Serial Cross-Sectional Analysis. JAMA. 2025 Nov 11;334(18):1638-1649.
2) Global Initiative for Asthma (GINA). Global Strategy for Asthma Management and Prevention. Updated report (annual). Available at: https://ginasthma.org/ (accessed 2025).
3) Kigali Amendment to the Montreal Protocol on Substances that Deplete the Ozone Layer (2016) — global agreement to phase down hydrofluorocarbons. United Nations Environment Programme. https://ozone.unep.org/treaties/montreal-protocol/kigali-amendment.
4) NHS England. Greener inhaler prescribing resources and guidance for reducing the carbon footprint of respiratory care. NHS England — Net Zero and greener NHS materials (various publications, 2019–2023). https://www.england.nhs.uk/greenernhs/ (accessed 2025).
Author note
This article is a critical interpretation of Feldman et al.’s JAMA analysis for clinicians, health system leaders, and policymakers. It summarizes key findings, interprets clinical implications, and outlines pragmatic strategies and research priorities to reduce the climate impact of respiratory care while safeguarding patient outcomes.
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