Inhalers are life-saving tools for millions of people living with asthma and chronic obstructive pulmonary disease (COPD).
But new research from UCLA Health has revealed that these common medical devices come with a serious environmental cost.
The study, published in JAMA, found that inhalers in the United States produce over 2 million metric tons of carbon emissions every year—about the same amount created by 530,000 gas-powered cars on the road annually.
This is the largest study so far to measure the climate impact of inhalers in the U.S.
Researchers analyzed data from 2014 to 2024, looking at three main types of inhalers used to deliver asthma and COPD medications.
The biggest contributor to emissions was the metered-dose inhaler (MDI), which accounted for 98% of all inhaler-related emissions.
These inhalers use hydrofluoroalkane (HFA) propellants to push medication into the lungs. HFAs are powerful greenhouse gases, once common in aerosol sprays, and can trap hundreds to thousands of times more heat in the atmosphere than carbon dioxide.
In contrast, dry powder inhalers and soft mist inhalers work without propellants and have a much smaller environmental footprint.
They deliver medicine through the user’s own breath or a mechanical device instead of a chemical spray.
Dr. William Feldman, a pulmonologist and health services researcher at UCLA’s David Geffen School of Medicine, led the study.
He explained that inhalers are just one example of how the U.S. health care system contributes to climate change.
“Inhalers add to the growing carbon footprint of the health care system, putting many patients with chronic respiratory disease at risk,” Feldman said.
“On the upside, there is a tremendous opportunity to make changes that protect both patients and the planet by using lower-emission alternatives.”
To conduct the study, researchers used a large national database that tracks inhaler prescriptions down to the specific product level. They then estimated emissions based on academic models and categorized results by factors such as drug type, manufacturer, and insurance coverage.
The team now plans to explore inhaler emissions in specific patient groups, such as those using Medicaid, and compare the effectiveness of high- and low-emission inhalers within the same treatment category.
They also want to investigate how pharmaceutical companies set prices and patents for new, eco-friendly inhalers.
Dr. Feldman emphasized that understanding the scale of the problem is key to creating change. “Once we know what’s driving these emissions, we can target solutions that lower them—helping both patients and the environment,” he said.
This research highlights an important balance: protecting individual health while also caring for the planet’s health.
