(CNN)Asthma sufferers could sharply reduce their carbon footprint by swapping commonly used inhalers for "greener" alternatives, a study from the University of Cambridge has found.
By swapping metered-dose inhalers for dry powder inhalers, users could reduce their carbon emissions equivalent to reducing their meat consumption or recycling, researchers said Wednesday.
But patients have been warned not to make such changes without medical advice.
Inhalers are used to treat the symptoms of conditions such as asthma by releasing medicine straight into a patient's lungs, widening the airways and making it easier to breathe.
Metered-dose inhalers contain liquified, compressed gas hydrofluoroalkane (HFA) -- a greenhouse gas -- which acts as a propellant to atomize the drug being delivered and to pump it out to the user.