A new study reveals that inhalers used for asthma and chronic obstructive pulmonary disease (COPD) in the United States have a significant environmental impact, generating carbon emissions equivalent to that of approximately 530,000 gasoline-powered cars annually. The research, the largest of its kind in the U.S., quantifies the climate pollution from these essential medical devices and highlights a path toward reducing their carbon footprint without compromising patient care.
The decade-long analysis, published in the Journal of the American Medical Association, found that from 2014 to 2024, inhalers were responsible for an estimated 24.9 million metric tons of carbon dioxide equivalent emissions. The vast majority of these emissions, 98%, are attributed to one specific type of inhaler: the metered-dose inhaler (MDI). These devices, often called “puffers,” use hydrofluoroalkane (HFA) as a propellant to deliver medication, a potent greenhouse gas that contributes to global warming and, in a concerning feedback loop, can exacerbate the respiratory conditions they are designed to treat.
Understanding Inhaler Emissions
The Role of Propellants
The primary driver of the high carbon footprint of metered-dose inhalers is not the medication itself but the HFA propellant used to aerosolize it. HFAs are powerful greenhouse gases, capable of trapping heat in the atmosphere thousands of times more effectively than carbon dioxide. While essential for the function of MDIs, these propellants are released into the atmosphere with each puff, contributing to the overall environmental impact of the healthcare sector. The study by researchers at UCLA Health and Harvard University underscores the scale of these emissions, which have been a known issue but are now quantified in a large-scale analysis of the U.S. healthcare system.
Types of Inhalers
There are three main types of inhalers approved for asthma and COPD, each with a different environmental impact. Metered-dose inhalers, the most common type and the focus of the study’s findings, account for the overwhelming majority of emissions. In contrast, dry powder inhalers (DPIs) and soft mist inhalers (SMIs) are far more environmentally friendly. These devices deliver medication to the lungs without the need for a propellant, resulting in a much smaller carbon footprint. The study’s authors suggest that transitioning to these lower-emission alternatives, when medically appropriate, presents a significant opportunity to reduce the climate impact of respiratory care.
The Scale of the Problem
A Decade of Data
The study analyzed a national drug database, examining inhalers used by patients with commercial insurance, as well as those covered by Medicare and Medicaid, between 2014 and 2024. This comprehensive dataset allowed researchers to calculate the total emissions from the three types of inhalers over a ten-year period, revealing the sustained and substantial contribution of these devices to greenhouse gas emissions. The findings show an annual emission rate of over 2 million metric tons of carbon dioxide, a figure that highlights the cumulative effect of millions of individual inhalers used daily across the country.
The Healthcare Carbon Footprint
The emissions from inhalers are part of the broader issue of the healthcare industry’s contribution to climate change. “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. This study provides a specific and quantifiable example of how medical products can have unintended environmental consequences, and it comes at a time of increasing awareness of the need to decarbonize all sectors of the economy, including healthcare.
Potential for Change
Low-Emission Alternatives
The existence of effective, low-emission alternatives to MDIs is a key takeaway from the study. Dry powder and soft mist inhalers offer a clear path to reducing the carbon footprint of respiratory care, and in many cases, they can be used as a direct substitute for HFA-propelled devices. The choice of inhaler depends on the individual patient’s needs and ability to use the device correctly, but the study suggests that a deliberate shift in prescribing practices could lead to a significant reduction in emissions. This approach is not without precedent; for example, the U.S. Veterans Administration has already prioritized the use of dry-powder inhalers, resulting in a more than 68% reduction in planet-warming gases from 2008 to 2023.
Patient and Planet Health
The authors of the study and an accompanying editorial emphasize that the goal is not to discourage the use of inhalers but to encourage a more environmentally conscious approach to prescribing them. The link between climate change, air pollution, and respiratory health is well-established, with rising temperatures and worsening air quality expected to increase the prevalence and severity of conditions like asthma. By opting for lower-emission inhalers when possible, healthcare providers and patients can contribute to a healthier planet, which in turn can lead to better respiratory outcomes for everyone. The study authors express optimism, stating that “there is tremendous opportunity to make changes that protect both patients and the planet.”
Moving Forward
The findings of this study provide a strong case for re-evaluating the environmental impact of commonly prescribed medical devices. As the healthcare industry grapples with its own carbon footprint, the case of inhalers serves as a model for how changes in clinical practice can lead to significant environmental benefits. For the millions of Americans who rely on inhalers to manage their respiratory conditions, the availability of effective and eco-friendly alternatives means that patient health and planetary health do not have to be mutually exclusive.
