Asthma inhalers linked to carbon emissions equal to 530,000 cars, study finds
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Inhalers used for asthma and chronic obstructive pulmonary disease (COPD) are producing carbon emissions comparable to those of more than half a million cars, according to new research from UCLA Health.
Published in JAMA, the study is the largest analysis of its kind to evaluate the environmental impact of inhalers in the United States.
Researchers found that these medical devices released over 2 million metric tons of carbon dioxide annually between 2014 and 2024 - equivalent to the yearly emissions of 530,000 gasoline-powered vehicles.
The team examined three types of inhalers commonly prescribed for asthma and COPD. Metered-dose inhalers (MDIs) were identified as the main contributors, accounting for 98% of total emissions. These devices use hydrofluoroalkane (HFA) propellants, which are potent greenhouse gases once used in aerosol sprays.
Dry powder inhalers and soft mist inhalers, which do not rely on propellants, had much lower environmental impact. Researchers suggested switching to these alternatives when medically suitable to reduce emissions without compromising patient care.
Dr. William Feldman, a pulmonologist and health services researcher at the David Geffen School of Medicine at UCLA and the study’s lead author, said that inhalers contribute to the growing carbon footprint of the US healthcare system, thereby putting many patients with chronic respiratory diseases at risk. He added that there was, however, a tremendous opportunity to protect both patients and the planet by adopting lower-emission alternatives.
The research team used a national database of inhaler prescriptions categorised by National Drug Code (NDC) and estimated emissions using validated academic models. They analysed data across variables such as drug type, device type, propellant type, therapeutic class, branded status, manufacturer, payer, and pharmacy benefit manager.
Experts are now urging healthcare providers and policymakers to promote more sustainable inhaler options. Researchers also plan to extend their study to assess emissions among specific patient groups, including those covered by Medicaid.
Future work will examine whether lower-emission inhalers in the same therapeutic class produce comparable clinical outcomes and explore how pharmaceutical companies might use pricing and patent strategies as they introduce newer, eco-friendly inhaler technologies.
Feldman said that a crucial first step toward driving change was understanding the true scale of the problem. From there, he added, it would be possible to identify the sources of these emissions and develop targeted strategies to reduce them, ultimately benefiting both patients and the environment.