A Queen's University study published in PLOS ONE analyzed over 750,000 inhaler prescriptions in Ontario from 2017 to 2023. It found that metered-dose inhalers (MDIs), which use potent greenhouse gas propellants, still account for 70 to 80 percent of new prescriptions. A single MDI emits as much as driving a midsized car 139 kilometers. Despite lower-carbon options like dry powder inhalers being available and updated clinical guidance, prescribing habits have not shifted significantly, even after pandemic disruptions. The study highlights a gap between awareness and practice in healthcare. Researchers point to policy-level changes such as drug coverage frameworks and prescribing feedback systems as necessary to reduce emissions without compromising patient care. Ontario lags behind the UK and Scandinavian countries in adopting lower-emission inhalers, showing room for improvement in Canada's healthcare sustainability efforts.
