Common Inhalers Found to Significantly Contribute to Global Warming
New research has uncovered an unexpected source of climate pollution: medical inhalers used to treat asthma and other chronic lung diseases. While these devices are vital for millions of Americans, the study found that their use contributes substantially to greenhouse gas emissions — equivalent to the pollution from more than half a million cars each year.
According to the Asthma and Allergy Foundation of America, around 34 million Americans live with chronic lung conditions such as asthma or chronic obstructive pulmonary disease (COPD). Rising global temperatures and worsening air quality have made these conditions more common. Ironically, the very inhalers people depend on for relief may be adding to the climate problem.
Metered-dose inhalers (MDIs) are the main culprits. These small, handheld devices deliver medication through a burst of propellant gases known as hydrofluoroalkanes (HFAs). Although safe for patients, HFAs are powerful greenhouse gases — thousands of times more effective at trapping heat in the atmosphere than carbon dioxide.
The Scale of the Problem and Possible Solutions
A study published in JAMA revealed that MDIs account for 98% of all climate pollution from inhalers. Between 2014 and 2024, pharmacies dispensed around 1.6 billion inhalers in the United States, releasing an estimated 24.9 million metric tons of carbon dioxide equivalent (CO₂e) emissions annually. This rise represents a 24% increase over the past decade.
Dr. William Feldman, one of the study’s authors and a pulmonologist at UCLA, emphasized that while inhalers are essential, their environmental impact is surprisingly large. “It’s hard to imagine such small products contributing so much,” he noted. “But this is a fixable issue — alternatives already exist.”
Some of those alternatives are dry-powder inhalers (DPIs) and soft mist inhalers, which don’t rely on HFAs. Research has shown that switching to these eco-friendlier options can significantly reduce emissions. For example, the U.S. Veterans Administration began prioritizing DPIs over MDIs in 2021, cutting related emissions by more than 68% from 2008 to 2023.
Despite this progress, challenges remain. Certain patients — including young children, older adults, or those with severe breathing difficulties — may not be able to use dry-powder versions effectively. DPIs can also be more expensive, and insurance coverage for them remains limited. The U.S. market currently offers fewer DPI options than Europe, where advanced models that combine fast-acting relief with anti-inflammatory properties are already available.
Under the Kigali Amendment, the United States has pledged to phase down hydrofluorocarbons by 85% before 2036, which will likely include reducing HFA-based inhaler production. However, complete elimination isn’t feasible since some patients will still require these devices for effective treatment.
Dr. Alexander Rabin and colleagues, in an accompanying editorial, wrote that adjusting inhaler use “may be among the most promising opportunities for the health sector to decarbonize.” They emphasized that a transition toward greener options can occur “without compromising patient care.”
For individuals like Kate Bender of the American Lung Association, who also lives with asthma, the findings are frustrating. “It’s ironic that the medication I need to breathe contributes to climate change,” she said. Still, experts caution that patients should never switch inhalers without medical advice.
As Dr. Feldman noted, inhalers are not the biggest driver of global warming compared to industries like energy or transport — but every reduction helps. “Each small step toward cleaner alternatives matters,” he said. “It’s on all of us to do our part in lowering emissions — even in medicine.”
