Written By: Team Pharmacally
Inhalers play a central role in managing asthma and chronic obstructive pulmonary disease (COPD). New study published in JAMA shows that they come with a hidden climate cost. This analysis estimates how much greenhouse gas (GHG) burden is tied to inhaler use in the U.S. from 2014 to 2024, and identifies how shifts in prescribing and device choice could lower emissions.
The study highlights a growing environmental challenge: the use of metered-dose inhalers in respiratory care is generating enormous greenhouse gas emissions, primarily due to their hydrofluoroalkane (HFA) propellants. Over the past decade, these emissions have risen by 24% which roughly equal to the yearly emissions from more than half a million gasoline cars in the U.S.
This article walks through the study’s findings, its limitations, clinical and policy implications, and what it means for patients, clinicians, and public health.
Background: Why Inhalers Matter for Climate
Metered-dose inhalers (MDIs) are essential devices that deliver asthma and COPD medication directly into the lungs and give quick relief for millions of people living with chronic respiratory conditions. However, traditional MDIs use hydrofluoroalkane (HFA) propellants, which are powerful greenhouse gases capable of trapping thousands of times more heat per molecule than carbon dioxide. While each inhaler contains only a small amount of these propellants, the collective environmental impact from millions of inhalers in use is substantial. In contrast, dry powder inhalers (DPIs) and soft mist inhalers do not rely on these propellants or use much less quantity; making their carbon footprint significantly lowers per dose. Recognizing this, the many countries are facing growing international and domestic pressure to phase down high global warming potential (GWP) hydrofluorocarbons. Once happened, this transition will strongly influence the future of the inhaler market.
Study Design & Methods
The researchers analyzed U.S. outpatient pharmaceutical data to estimate the greenhouse gas emissions linked to inhaler use. They gathered aggregated dispensing information based on National Drug Codes, inhaler types, manufacturers, and payers. Each inhaler was then assigned an estimated emission value in carbon dioxide equivalents (CO₂e) using established propellant emission models and prior validation studies. The data were further categorized by device type such as metered-dose inhalers (MDIs), dry powder inhalers (DPIs), and soft mist inhalers as well as by therapeutic class, propellant type, brand status, and manufacturer. Finally, the team calculated the social cost of these emissions by applying standard carbon cost models to estimate the economic damage caused by inhaler-related greenhouse gas emissions.
Results
Between 2014 and 2024, about 1.6 billion inhaler units were dispensed across the United States. During this period, the total greenhouse gas emissions linked to inhaler use were estimated at 24.9 million metric tons of carbon dioxide equivalent (CO₂e). Annual emissions rose by about 24%, increasing from 1.9 million metric tons in 2014 to 2.3 million metric tons in 2024, showing a steady upward trend in the environmental impact of inhaler use.
Nearly all of these emissions about 98% came from metered-dose inhalers (MDIs). Within this group, short-acting β-agonists, inhaled corticosteroid/long-acting β-agonist (ICS-LABA) combinations, and inhaled corticosteroids were the major contributors. Just three products albuterol, budesonide-formoterol, and fluticasone propionate were responsible for roughly 87% of total emissions, highlighting how a few widely used inhalers account for most of the climate burden.
The study also estimated the broader economic impact of these emissions. Over the decade, the social cost the estimated monetary damage to society from climate change effects was calculated at $5.7 billion, with a range between $3.5 billion and $10 billion.
Overall, the data show that inhaler-related emissions have continued to rise, largely due to growing use of MDIs and limited adoption of lower-emission alternatives. The findings suggest that targeting a small number of high-impact inhaler types and promoting eco-friendlier options could meaningfully reduce the sector’s overall carbon footprint.
Inhaler Type | Percentage of Claims | Percentage of Emissions | Average Annual CO2e Emissions | Environmental Impact |
Metered-Dose Inhalers (MDI) | 70% | 98% | 2.3 million metric tons | Equivalent to 530,000 cars |
Dry Powder Inhalers (DPI) | 30% | 2% | Much lower | Propellant-free, lower cost to environment |
Soft Mist Inhalers | Minimal | Minimal | Minimal | Propellant-free |
Interpretation & Limitations
The study highlights that inhaler use, especially from metered-dose inhalers (MDIs), makes a significant contribution to U.S. greenhouse gas emissions. Since MDIs account for nearly all inhaler-related emissions, switching patients when clinically appropriate to lower-emission options like dry powder or soft mist inhalers could significantly reduce the overall climate impact. The authors also emphasize that pricing, insurance coverage, and regulatory support will be key in encouraging this transition.
However, the analysis has some limitations. The emission estimates are based on modeling rather than direct measurements, and real-world use may vary. Not all patients can use dry powder inhalers, particularly children or those with severe airflow limitation. Availability and affordability of alternatives also differ across insurance plans and regions. Finally, because the data cover the period up to 2024, future innovations in inhaler technology or changes in prescribing patterns could alter these results.
Dr. William Feldman (Lead Author, Pulmonologist, UCLA) Stated that “a key first step to driving change is understanding the true scale of the problem,” noting, “we can identify what’s fueling these emissions and develop targeted strategies to reduce them benefiting both patients and the environment.” He also highlighted, “there is tremendous opportunity to make changes that protect both patients and the planet by utilizing lower-emission alternatives.
Implications for Clinicians, Policy & Patients
For Clinicians
Doctors play a key role in reducing inhaler-related emissions. When medically suitable, they can consider switching patients from metered-dose inhalers to lower-emission options like dry powder or soft mist inhalers at the same time educating patients about proper inhaler use.
For Policymakers and Health Systems
Health authorities and insurers can drive change by supporting access to low-emission inhalers through favorable pricing, coverage, and reimbursement policies. Regulatory bodies can also encourage the development and approval of inhalers that use low global warming potential propellants, align respiratory care with broader climate goals.
For Manufacturers and Innovators
Pharmaceutical companies are urged to invest in greener technologies, including next-generation inhalers with low-GWP propellants or propellant-free systems. Greater transparency about the carbon footprint of inhaler products could also guide clinicians and patients toward more sustainable choices, promoting long-term environmental responsibility in respiratory medicine.
References
Feldman WB, Han J, Raymakers AJN, Furie GL, Chesebro BB. Inhaler-Related Greenhouse Gas Emissions in the US: A Serial Cross-Sectional Analysis. JAMA. Published online October 06, 2025. doi:10.1001/jama.2025.16524
UCLA Health study finds inhalers for asthma and COPD drive significant greenhouse gas emissions, Oct 06 2025, UCLA Health, https://www.uclahealth.org/news/release/ucla-health-study-finds-inhalers-asthma-and-copd-drive