Inhalers used to treat asthma and chronic obstructive pulmonary disease (COPD) may be contributing significantly to carbon emissions, according to a new study by UCLA Health. The research, published in JAMA, is the largest of its kind to assess the environmental impact of inhalers in the US.
The study found that inhalers produced more than 2 million metric tons of carbon emissions each year over the past decade, roughly equal to the annual emissions of 530,000 gasoline-powered cars.
Researchers analysed data from 2014 to 2024, covering three types of inhalers approved for asthma and COPD treatment. Metered-dose inhalers (MDIs) were found to be the most environmentally harmful, responsible for 98% of total emissions. These inhalers use hydrofluoroalkane (HFA) propellants, which are potent greenhouse gases formerly used in aerosol sprays.
In contrast, dry powder inhalers and soft mist inhalers do not rely on propellants and have a far smaller carbon footprint. Researchers suggest that switching to these lower-emission alternatives, when medically appropriate, could reduce the environmental impact of respiratory care.
Experts now urge healthcare providers and policymakers to consider more eco-friendly options in managing asthma and COPD without compromising patient health.
"Inhalers add to the growing carbon footprint of the US healthcare system, putting many patients with chronic respiratory disease at risk," said Dr William Feldman, a pulmonologist and health services researcher at the David Geffen School of Medicine at UCLA, and the study's lead author. "On the upside, there is tremendous opportunity to make changes that protect both patients and the planet by utilizing lower-emission alternatives."
Researchers conducted the study using a comprehensive US database capturing inhaler prescriptions at the National Drug Code (NDC) level. Emissions were then estimated using validated academic studies and analyzed by drug type, device type, propellant type, therapeutic class, branded status, manufacturer, payer, and pharmacy benefit manager.
Researchers plan to expand their research to examine inhaler-related emissions in specific patient populations, such as the Medicaid population. They will also compare clinical outcomes between of lower- and higher-emission inhalers in the same therapeutic class and explore pricing and patenting strategies that pharmaceutical companies may use as they roll out lower-emission inhaler technologies.
"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."
