Study finds US asthma inhalers produce same emissions as 500,000 cars

The inhalers people depend on to breathe are also warming the planet, producing annual emissions equivalent to more than half a million cars in the United States alone, researchers have said in a major new study.

Using a national drug database, researchers at the University of California, Los Angeles and Harvard University analysed global warming pollution from three types of inhalers used to treat asthma and chronic obstructive pulmonary disease (COPD) between 2014 and 2024.

The study, published in the Journal of the American Medical Association (JAMA) on Monday, found that inhalers used by US patients with commercial insurance and the government-run programmes Medicaid and Medicare generated 24.9 million metric tons of carbon dioxide equivalent over the decade.

Metered-dose inhalers,