Every time they use their puffers, up to six million Canadians with respiratory diseases like asthma and emphysema unknowingly release dangerous greenhouse gasses into the air. One hundred puffs of a metered dose inhaler (MDI) produce as many greenhouse gases (GHGs) emissions as a 290-kilometre drive in a gas-powered car.
So now a group of health professionals at the Toronto Academic Health Science Network are steering patients and physicians toward more climate-conscious and clinically sound ways to control respiratory disease. The health group known as Sustainable Health System Community of Practice is using a combination of proper inhaler techniques and lower-carbon alternatives, such as dry powder inhalers, to reach that goal. The group also recommends no longer prescribing puffers for the 30 per cent of users who don’t need them.
Common metered dose inhalers like Ventolin, the ubiquitous blue puffers that dispense salbutamol, contain hydrofluorocarbons, liquefied-gas propellants necessary to atomize the medication for delivery to the lungs. They become potent greenhouse gases when released into the atmosphere, which leads to global warming. More than 90 per cent of the GHGs are released when patients use a puffer. The remainder may leak out when the dispensers end up in landfills.
For those with respiratory diseases, it is like being caught on a hamster wheel. As fossil fuel burning, air pollution and global warming cause more respiratory diseases and worsen symptoms, the demand for puffers increases, which in turn releases more GHGs. The demand for puffers increased four per cent in the Global North and 18 per cent in the Global South in 2016-17, according to the Intergovernmental Panel on Climate Change.
“Many patients on these puffers do not even need them,” said Dr. Kimberly Wintemute, a family physician and lead of the Toronto working group. For example, many patients are put on puffers for persistent coughs after a cold and may continue using them unnecessarily. Wintemute points out a post-viral cough lasts 18 days, on average. The cause is most often post-nasal drip, a condition that responds to nasal sprays, not puffers, Wintemute said.
Up to a third of patients clinically diagnosed with asthma do not have the disease when objectively tested, according to the Canadian Thoracic Society (CTS). These patients are needlessly using puffers, exposing them to unnecessary side-effects and costs. CTS recommends gold standard breathing tests, such as spirometry, be done before puffer prescriptions in all patients older than six, the age at which patients can reliably complete these tests.
According to a 2018 study, prescribed drugs make up 21 per cent of Canadian health-care GHG emissions, a number on par with air transport.
“Patients' jaws drop to the floor,” said Wintemute of the reaction from patients when they find out about the environmental effects of their metered dose inhalers. Studies have shown that patients care about the environmental impacts of their medical choices.
“One of my patients who came to see me for an unrelated concern saw our poster,” said Wintemute as she holds up a poster with pictures of MDIs (puffers) and the caption, Did you know 100 puffs = 290-km drive in carbon footprint, “and asked to be switched off.”
Nearly 75 per cent of puffers prescribed in Canada are conventional metered dose inhalers. But there are alternatives, including dry powder and mist inhalers. Both have a lower global warming potential because they do not use propellants.
However, environmental scientist Harish Kumar Jeswani writes in his 2019 study that dry powder inhalers pose some environmental risks; they score worse in eight out of 12 other environmental hazards compared to conventional puffers. They rate higher on the scale for marine and human toxicity. These toxic effects are driven by the high amount of plastic and aluminum required in production. Moreover, there are currently no consistent systems in place to reuse the plastics and aluminum in these products.
Yet when all factors are considered, dry powder inhalers have a carbon footprint that’s 10 times smaller than metered dose inhalers, Jeswani’s 2020 study and others show.
Susan Goodwin, an asthma patient, prefers using a dry powder inhaler. “It doesn’t taste as bad and the medication delivers better to my lungs,” she said. But she has to pay more for it; commonly used dry powder inhalers are more expensive.
Research is underway to launch metered dose inhalers with hydrofluorocarbon propellants that have lower global heating properties, such as HFC 152a. MDIs with HFC-152a have the lowest environmental impact of most inhalers on the market. At least two pharmaceutical companies, Chiesi and AstraZeneca, are working on bringing these products to the European market by 2025. It is unclear if these targets will be met or how soon they will be available in Canada.
For patients who can’t or don’t want to stop using their metered dose inhalers, Wintemute and her colleagues are teaching better inhaler techniques. A U.K. study found that with proper training, patients had a 35 per cent improvement in inhaler technique, leading to improved disease control and a reduction in unnecessary puffer use.
Asthma patients need an understanding of both treatment and rescue inhalers and good techniques. “It can be life-changing,” said Dr. Tamsin Ellis, a family doctor in London and a member of Greener Practice, the U.K.’s primary care sustainability network.
The Toronto working group is now collaborating with similar groups across Canada under the sustainable health system initiative CASCADES.
Along the way, the group is identifying roadblocks to providing improved respiratory care. “Access to spirometry, managing disposal of these puffers, drug plan coverage issues — these are all issues we are uncovering,” said Fiona Miller, CASCADES’ director and a professor of health policy at the Dalla Lana School of Public Health in Toronto.
Ellis, Miller and Wintemute want to see government policy to tackle air pollution, which is the major driver of respiratory diseases. The work on inappropriate inhaler use is a drop in the bucket compared to the effects of industrial and road traffic pollution, they note. But any reduction in greenhouse emissions counts, said Wintemute. “Frankly, there is no time to wait.”
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