The Asthma and Respiratory Foundation is urging healthcare practitioners and people with respiratory conditions to discuss the environmental impact of different inhalers when considering treatment options.

"Many people may not be aware of the impact their inhalers have on the environment or that there are usually more environmentally friendly options available," explains Foundation Chief Executive Letitia Harding. "We want to encourage healthcare practitioners to have these conversations with patients, so there is a wider understanding of this issue."

It is known that pressurised metered dose inhalers (pMDIs), like the familiar blue puffer used by many New Zealanders, have a significant environmental impact. It is estimated that the carbon footprint of a 200-dose inhaler of this type is equal to a 290km journey in a small car. However, other options like dry powder inhalers and soft mist inhalers have approximately a 95% lower carbon footprint.

A recent study from the University of Otago investigated patients’ and prescribers’ attitudes to the environmental impact of inhalers. The study found that most patients surveyed were unaware of the environmental impact of their inhaler, but also that most would be willing to change their inhaler type for environmental reasons if their practitioner recommended it. The practitioners surveyed were more aware of environmental impacts and were also willing to consider these impacts when deciding which inhalers to recommend.

Both patients and prescribers thought that the effectiveness of the inhaler and its ease of use were the most important considerations. "There was some concern that dry powder inhalers would not be suitable for some patients, particularly younger children and some older people who do not have a strong enough inhalation to use them properly. It is true that dry powder inhalers are not the best choice for everyone, but overall dry powder inhalers have been shown to be as effective as pressurised metered dose inhalers in controlling the symptoms of both asthma and COPD. For many patients, these inhalers may lead to better health outcomes, while also being much better for the environment," says Professor Bob Hancox, Consultant Respiratory Physician and one of study authors.

"The healthcare sector in OECD countries is estimated to contribute between 3-8% of the nation’s total greenhouse gas emissions and inhalers are an important contributor to this" explains Professor Hancox.

Professor Hancox emphasises that anyone wanting to change their medication due to environmental concerns, should do so under medical advice. "Poorly-managed asthma or COPD is not just bad for your health: it will also be bad for the environment. Any decision to change your medication should be done carefully so that you maintain or improve your health as well as benefitting the environment."

The study was done by a group of final year medical students at the Dunedin School of Medicine and was published in the New Zealand Medical Journal on 14 April 2023:

Investigating attitudes and insights into the global warming impact of inhalers. Matthew J Woodall, John Ma, Kate Emett, Amelia PE Hamblin, Katie Knowles, Tom Hyunwoo Lee, Wilson Mitchell, Wennarator Irae Ofoia, Letoe Renee Topeto, John D Dockerty, Robert J Hancox.

New Zealand Medical Journal 2023 Apr 14; 136(1573)