A new study has revealed that the inhalers millions of Americans rely on to breathe are also quietly contributing to global warming, releasing as much greenhouse gas each year as more than half a million cars.
Researchers from the University of California, Los Angeles (UCLA), and Harvard University analysed data from a national drug database covering the decade between 2014 and 2024. Their findings, published Monday in the Journal of the American Medical Association (JAMA), estimate that inhalers used under commercial insurance and government programs such as Medicaid and Medicare produced 24.9 million metric tons of carbon dioxide equivalent during that period.
The major culprit, according to the study, is the metered-dose inhaler — commonly known as the “puffer.” These inhalers account for an astonishing 98 percent of total emissions because they rely on hydrofluoroalkane (HFA) propellants, powerful greenhouse gases that deliver medication through pressurized canisters.
In contrast, dry powder and soft mist inhalers—which rely on a patient’s breath or transform liquid medicine into a fine mist—cause far less harm to the environment. Yet, the majority of U.S. patients continue to use the older, more polluting devices.
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“Five hundred and thirty thousand cars on the road each year is a lot,” said lead author Dr. William Feldman, a pulmonologist at UCLA. “What makes this particularly significant is that it’s fixable. There are easy ways to reduce emissions without compromising patient care.”
Medically, only a small fraction of patients actually require puffers. Young children, who often use spacers to aid medication delivery, and frail older adults with limited lung strength may need them. But for most others, switching to cleaner alternatives would work just as effectively.
Feldman pointed out that countries such as Sweden and Japan have already transitioned largely to environmentally friendly inhalers, achieving the same medical results while drastically cutting emissions.
The study highlights a growing dilemma for modern medicine: life-saving treatments that come with an environmental cost — and an urgent call to rethink how healthcare contributes to the planet’s carbon footprint.