Asthma patients using metered-dose inhalers emit up to 140kg CO2e yearly, equivalent to driving 97km, due to HFC propellants.

Singaporean scientists have found that asthma patients using metered-dose inhalers release about 140kg of CO2 equivalent annually—equivalent to driving 97km—due to hydrofluorocarbon propellants. Dry powder inhalers produce less, averaging 121kg CO2e per patient. Research from SingHealth Polyclinics, based on data from over 23,000 patients, shows poor asthma control leads to higher inhaler use and greater emissions. Experts urge better self-management, trigger avoidance, and a shift to lower-emission inhalers to reduce both health risks and environmental impact. Findings were published in July and August 2025.