Climate pollution from inhalers has the impact of half a million cars per year, study finds

Dr. William Feldman discusses the new study which finds that inhalers approved for asthma may be one of the top contributors to climate pollution.

The people who are most vulnerable to the hard-to-breathe air that comes with climate change may inadvertently be adding to the problem, new research finds.

About 34 million Americans have a chronic lung disease, including 28 million who have asthma, according to the Asthma and Allergy Foundation of America – and the number is expected to grow as higher temperatures bring more weather phenomena that trigger breathing issues like droughts, floods and wildfires.

• Read more: More than 4.6 million Canadians have asthma, according to Asthma Canada

To treat conditions like asthma and chronic obstructive pulmonary disease, millions use what doctors often call metred dose inhalers, small boot-shaped devices that spray set doses of medication into the lungs in a quick burst using propellants called hydrofluoroalkanes, or HFAs.

Studies published Monday in the journal JAMA found that medication inhalers are “substantial” contributors to planet-warming pollution. It’s not the medicine itself that’s the problem; rather, it’s the HFAs.

When released into the air, HFAs trap heat in the atmosphere and have a global warming potential thousands of times more powerful than carbon dioxide, meaning even a small amount of HFA can cause problems, studies show.

In one year alone, one of the new studies says, planet-warming pollution from inhalers were the equivalent of driving more than half a million cars, or the same as electricity requirements for 470,000 homes, the study said.

Metreed-dose inhalers were responsible for 98 per cent of the climate pollution from inhalers, the study found. People with lung conditions can’t live without them, but the researchers noted some might be able to switch to an alternative inhaler that emits fewer problematic propellants.

“They are these tiny little products, and it’s hard to imagine that they can be such contributors, but it’s an eminently fixable problem with other products available and other products coming. So it feels like a kind of low-hanging fruit to address the emissions issue,” said study co-author Dr. William Feldman, a pulmonologist and health services researcher at the University of California, Los Angeles.

In one of the new studies, researchers found that pharmacists dispensed 1.6 billion inhalers in the U.S. from 2014 to 2024, generating 24.9 million metric tonnes of annual carbon dioxide equivalent emissions (CO2e). Annual emissions increased 24 per cent from 1.9 million to 2.3 million metric tons of CO2e over that decade.

The other study published Monday shows that concerted efforts to reduce traditional inhaler use can make a difference.

HFAs aren’t as harmful for the ozone layer as chlorofluorocarbon formulation inhalers that were phased out in the US from 2009 to 2013. But HFA inhalers aren’t the most earth-friendly option, either.

Since 2021, the U.S. Veterans Administration has prioritized dry-powder inhalers over traditional versions with propellants, and the shift reduced planet-warming gases by more than 68 per cent from 2008 to 2023, the study found.

Under the Kigali amendment ratified in 2016, the U.S. committed to reduce hydrofluorocarbons by about 85 per cent before 2036, and HFA inhalers are among the hydrofluorocarbons that will probably be phased down. But some will still need to be available because not everyone can use alternative inhalers.

Young children have to use spacers, holding chambers that allow the patient to breathe in the medication slowly so more of it reaches the lungs, and a spacer would hinder a dry-powder inhaler’s effectiveness. Some older people or those who are frail may not be able to generate enough of a strong, quick breath to effectively inhale the dry powdered version of the medicine.

There can also be a price barrier with dry-powder inhalers, since many of the versions that use HFAs are generic and less expensive. And insurance doesn’t often cover the dry-powder kind.

The U.S. has fewer dry-powder inhalers available than in Europe, although some companies are testing other options. Some inhalers in Europe are able to provide fast-acting relief and have an anti-inflammatory element, but no such product has been approved in the U.S.

Even with those hurdles, changing the kind of inhalers people use “may be among the most promising opportunities for the health sector to decarbonize” since there are viable alternatives for most “and a path to reform that need not compromise care,” Dr. Alexander S. Rabin, Dr. Jyothi Tirumalasetty and Dr. Stephanie I. Maximous, wrote in an editorial published alongside the studies.

As a person with asthma, “it drives me crazy that the medication I use to address my symptoms drives climate change,” said Kate Bender, vice-president of national advocacy and public policy for the American Lung Association, which was not involved with the new studies. But, she says, the organization does not recommend that people make the switch to a different kind of inhaler if their current course of treatment works for them.

“Yes, we should get to a future where inhalers aren’t emitting greenhouse gasses, but as we get to that future … we need to make sure people still have access to inhalers with propellants and the other options,” Bender said.

In the grand scheme of things, Feldman noted, inhalers are a relatively small cause of climate change compared to the bigger culprits like traffic, agriculture, and power generation. But as a doctor who regularly treats people who can’t breathe because of it, he said, every little effort helps.

“It’s really on all of us to try to do our part in reducing emissions,” Feldman said.

By Jen Christensen, CNN