A new study published in the Journal of the American Medical Association (JAMA) has revealed that inhalers used for asthma and chronic obstructive pulmonary disease (COPD) produce over 2 million metric tons of carbon emissions annually. This is equivalent to the pollution generated by approximately 530,000 gas-powered cars on the road. The research, which spans data from 2014 to 2024, underscores the significant environmental impact of these essential medical devices, particularly the Metered-Dose Inhalers (MDIs), which use hydrofluoroalkane (HFA) propellants—potent greenhouse gases widely used in aerosol sprays.
According to the study, MDIs are predominantly responsible for 98% of the total emissions from inhalers over the past decade. In contrast, dry powder inhalers (DPIs) and soft mist inhalers (SMIs), which do not rely on propellants, have a much smaller environmental impact. Researchers analyzed emissions data for the three main types of inhalers approved for asthma or COPD, concluding that the transition to alternative inhaler technologies could significantly reduce the environmental burden while still providing effective treatment for patients.
The lead author of the study, Dr. William Feldman, a pulmonologist and health services researcher at the David Geffen School of Medicine at UCLA, emphasized the potential for making substantial progress in both patient care and environmental sustainability. “On the upside, there is tremendous opportunity to make changes that protect both patients and the planet by utilizing lower-emission alternatives,” Feldman wrote in a UCLA news release.
The study’s findings are based on data from a comprehensive national database of inhaler prescriptions, at the National Drug Code (NDC) level. Researchers used validated academic studies to estimate emissions by drug type, device type, propellant type, therapeutic class, branded status, manufacturer, and pharmacy benefit manager. This detailed analysis allows for a clear understanding of how different factors contribute to the overall emissions from inhalers.
Despite the environmental concerns, some pharmaceutical companies, such as AstraZeneca, have already committed to transitioning from pressurized MDIs to propellants with significantly lower global warming potential. The team of researchers plans to expand their investigation to evaluate inhaler emissions in specific patient groups, such as Medicaid recipients, and to compare the clinical outcomes of low- and high-emission inhalers within the same therapeutic class.
They also intend to explore how pricing and patent strategies might influence the adoption of newer, lower-emission inhaler technologies. “A key first step to driving change is understanding the true scale of the problem,” Feldman noted. “From there, we can identify what’s fueling these emissions and develop targeted strategies to reduce them – benefiting both patients and the environment.”