Carbon footprint impact on inhalers  

Christer Janson

Department of Medical Sciences: Respiratory, Allergy and Sleep Research, Uppsala University, Uppsala, Sweden

That inhalation therapy can harm the environment became apparent in the 1990s when pressurised metered dose inhalers (pMDI)s that used chlorofluorocarbons (CFC) had to be replaced because of the depleting effect of CFCs on atmospheric ozone. CFC-containing pMDIs were replaced with dry powder inhalers (DPI), soft mist inhalers (SMI) and pMDIs that used HFCs as propellant. There were large differences between countries in how CFC-pMDIs were replaced, with DPI becoming the dominating type of device in Sweden while pMDIs dominated in the UK [1].

It was recently discovered that HFCs also were problematic from an environmental perspective as the ones used in pMDIs (HFA 134a and HFA 227ea) had a considerable global warming potential of 1300 to 3000 times larger than that of CO₂. Consequently, the carbon footprint of treating asthma or COPD with pMDIs is approximately 20 times higher than giving a similar treatment using DPIs [2] or SMIs [3]. A retrospective analysis of a pragmatic trial indicated that it is possible to switch asthmatics from pMDI to DPI and thereby significantly reduce carbon footprints without losing asthma control [4].