Inhalers Found to Emit as Much Carbon as 500,000 Cars a Year

• Oct 08, 2025

Inhalers used to treat asthma and chronic lung diseases are responsible for a surprising amount of greenhouse gas emissions, new research shows. The study highlights how medical treatments designed to help people breathe better may also be worsening the very environmental conditions that make respiratory problems worse.

A study published Monday in the Journal of the American Medical Association found that inhalers approved for asthma and chronic obstructive pulmonary disease (COPD) produced an estimated 24.9 million metric tons of carbon dioxide equivalent emissions in the United States between 2014 and 2024. Researchers said this amount is roughly equal to the yearly emissions of about 530,000 gasoline-powered cars.

“Scaled across tens of millions of inhalers dispensed annually, these emissions drive global warming, exacerbating the very respiratory conditions inhalers are meant to relieve,” the study’s authors wrote in a related editorial.

According to the Asthma and Allergy Foundation of America, about 28 million Americans suffer from asthma and another 34 million have chronic lung disease. These numbers are expected to rise as climate change worsens air quality, leading to increased respiratory issues and more severe symptoms among those affected.

The study revealed that metered-dose inhalers — the common boot-shaped devices many people associate with asthma treatment — were the biggest contributors to carbon emissions, accounting for 98% of the total over the ten-year period. The emissions come not from the medicine itself, but from hydrofluoroalkane (HFA) propellants used to deliver the medication. HFAs are powerful greenhouse gases also found in aerosol sprays and refrigeration systems.

Dr. William Feldman, the study’s lead author and a pulmonologist at the David Geffen School of Medicine at UCLA, said the findings show that inhalers add to the healthcare sector’s growing carbon footprint. “There is tremendous opportunity to make changes that protect both patients and the planet by utilizing lower-emission alternatives,” Feldman said.

The research also identified alternatives such as dry powder inhalers and soft mist inhalers, which deliver medication without the use of propellants. These options are less damaging to the environment while still providing effective treatment for people living with chronic respiratory diseases.

The study urges healthcare providers and manufacturers to transition toward more sustainable inhaler options to help reduce emissions and safeguard both human health and the planet.