Asthma Inhalers Emit Carbon Equivalent To Half A Million Cars, Says Study

Los Angeles | October 8, 2025 A new study by UCLA Health has revealed that inhalers used for asthma and chronic obstructive pulmonary disease (COPD) release carbon emissions equal to those produced by around 530,000 gasoline-powered cars every year. Published in JAMA, this research is the largest of its kind in the United States, highlighting the hidden environmental cost of a commonly used medical treatment. According to the study, inhalers generated more than 2 million metric tons of carbon dioxide annually over the past decade. Researchers analyzed data from 2014 to 2024, studying three major inhaler types approved for asthma and COPD treatment. Among them, metered-dose inhalers (MDIs) were found to be the biggest contributors to emissions, accounting for 98% of the total. These inhalers use hydrofluoroalkane (HFA) propellants — gases once used in aerosol sprays — which are known to be potent greenhouse gases. On the other hand, dry powder inhalers and soft mist inhalers operate without such propellants, resulting in significantly lower emissions. Dr. William Feldman, lead author of the study and a pulmonologist at UCLA’s David Geffen School of Medicine, said the findings show an urgent need to rethink how respiratory diseases are managed. “Inhalers add to the growing carbon footprint of the healthcare system. But the good news is, we have the tools to reduce it — by switching to low-emission alternatives that still keep patients healthy,” he said. The researchers used a comprehensive U.S. database that tracked inhaler prescriptions down to the National Drug Code (NDC) level. They then calculated emissions using validated scientific studies, analyzing data by type of drug, device, propellant, manufacturer, and healthcare payer. Experts say this information can help health authorities and policymakers identify the main sources of medical emissions and make greener choices in treatment options. The study also emphasizes that environmental responsibility should not come at the cost of patient care. Instead, healthcare systems can transition to sustainable inhaler options when medically suitable. Researchers plan to extend their work by examining inhaler-related emissions among specific patient groups, such as those covered by Medicaid. They also intend to compare the clinical results of low- and high-emission inhalers in similar treatment categories and analyze how pricing and patenting could influence the adoption of eco-friendly options. Dr. Feldman added that understanding the true scale of the issue is only the first step. “Once we know the full impact, we can create focused strategies to reduce emissions — helping both patients and the planet,” he said. The study calls for collaboration between healthcare providers, pharmaceutical companies, and policymakers to make respiratory care more sustainable while maintaining its effectiveness for millions who rely on inhalers daily. Asthma Inhalers and the Environment A new UCLA Health study has revealed that asthma and COPD inhalers release carbon emissions equal to over 530,000 cars every year. Researchers found that metered-dose inhalers, which use hydrofluoroalkane propellants, are responsible for nearly all emissions, while dry powder and mist inhalers are far cleaner alternatives. Experts say switching to eco-friendly inhalers, where medically possible, can greatly reduce healthcare’s environmental footprint. The study highlights the balance between patient care and climate action, urging healthcare systems and policymakers to promote greener treatments without compromising on health or safety.