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Inhalers Produce More Than A Half-Million Cars' Worth of Carbon Emissions Annually
- October 7, 2025
- Dennis Thompson HealthDay Reporter
Inhalers provide breath-saving relief to people with asthma and COPD, but ultimately are undoing those good works by promoting climate change, a new study says.
Inhalers generated more than 2 million metric tons of carbon emissions annually over the past decade, researchers reported Oct. 6 in the Journal of the American Medical Association.
By researchers’ estimates, that’s equal each year to the emissions from roughly 530,000 gas-powered cars.
“Inhalers add to the growing carbon footprint of the U.S. health care system, putting many patients with chronic respiratory disease at risk,” lead researcher Dr. William Feldman, a pulmonologist and health services researcher at the David Geffen School of Medicine at UCLA, said in a news release.
Prior studies have linked climate change to an increase in asthma triggers. For example, pollen counts are higher and pollen season longer as a result of global warming, according to an April study published in the journal The Laryngoscope.
“Scaled across tens of millions of inhalers dispensed annually, these emissions drive global warming, exacerbating the very respiratory conditions inhalers are meant to relieve,” Dr. Alexander Rabin, a clinical associate professor of pulmonology at the University of Michigan, and co-authors wrote in an editorial accompanying the new study.
For the new study, researchers analyzed emissions from the three types of inhalers approved for asthma or COPD from 2014 to 2024. The team then used data on inhaler prescriptions to estimate how much carbon emissions were generated.
The team found that 1.6 billion inhalers were dispensed in the U.S. alone during that period, generating nearly 25 million metric tons of carbon dioxide emissions in total.
Annual emissions increased from 1.9 million metric tons of carbon emissions in 2014 to 2.3 million in 2024, the study found.
Metered-dose inhalers were responsible for 98% of all those emissions. These inhalers use hydrofluoroalkane propellants, which researchers say are potent greenhouse gases.
Ironically, metered-dose inhalers started using hydrofluoroalkane propellants in the late 2000s to ward off ozone layer depletion caused by the previous type of propellant, chlorofluorocarbons, according to the U.S. Food and Drug Administration (FDA).
The other two types of inhalers that are approved — dry inhalers and soft powder mist inhaler — are less harmful to the environment because they deliver medication to the lungs without requiring propellants, researchers said.
But dry inhalers can be harder to use because a person has to actively breathe in the medicine, rather than having a propellant push the drug deep into their lungs, according to the Allergy and Asthma Foundation of America.
Researchers next plan to examine inhaler-related emissions among specific types of patients, such as those covered by Medicaid.
They also intend to look at how well metered-dose inhalers treat asthma and COPD compared to dry inhalers and soft powder mist inhalers.
“A key first step to driving change is understanding the true scale of the problem,” Feldman said. “From there, we can identify what’s fueling these emissions and develop targeted strategies to reduce them — benefiting both patients and the environment.”
More information
The Allergy and Asthma Foundation of America has more on metered-dose inhalers versus dry inhalers.
SOURCES: UCLA, news release, Oct. 6, 2025; Journal of the American Medical Association, Oct. 6, 2025
