Asthma inhalers are critical for delivering small amounts of medication to people's lungs to improve breathing and help prevent asthma attacks, but those tiny puffs add up to a large environmental cost – the equivalent of emission from about 530,000 cars per year.

That translates to more than 2 million metric tons of carbon emissions from inhalers for asthma and chronic obstructive pulmonary disease annually for the past decade, according to a study out of UCLA and published Monday in the Journal of the American Medical Association. MORE: How much sleep do children get? Not as much as their parents think

"Inhalers add to the growing carbon footprint of the US healthcare system, putting many patients with chronic respiratory disease at risk," Dr. William Feldman, a pulmonologist

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