Doctors are to be issued a “climate aware” guideline to minimise the unnecessary use of aerosol asthma medications because they release the forever chemicals PFAS into the environment.

Lung experts have said most patients can change to less harmful inhalers without any consequences.

Some four million aerosol inhalers are prescribed in the Netherlands each year to a million and a half asthma sufferers and the propellant from a single inhaler equals the greenhouse effect of 320 kilometres in a petrol-driven car.

The PFAS in aerosol inhalers are not the same as in other aerosols and do not accumulate in the body. But when patients exhale TFA, a different type of PFAS, is formed which is harmful to the environment.

The medical sector produces some 7% of all greenhouse gases in the Netherlands.

While offering relief to sufferers, the gases contribute to global warming, which makes their condition worse. “It causes a longer flowering season, which means more pollen and more health problems. We are seeing the effects already,” children’s lung specialist Niels Rutjes told broadcaster NOS.

Too many people are using the aerosol inhaler, she said. “About 55% of the million and a half patients are using them but only 15% to 20% really need them.”

Powder inhalers, which require users to inhale without the help of a propellant, would be a good alternative, except for people who have trouble inhaling, such as the elderly and small children.

PFAS is a collective term for approximately 4,000 chemicals that do not degrade in the environment. For instance, PFAS are used in non-stick pan coatings and to make waterproof clothing. They can affect the immune system, fertility, unborn children, and organs such as the liver and the thyroid, and can cause cancer.

Cleaning up PFAS pollution in the Netherlands is set to cost billions of euros, given the “forever chemicals” could be present in up to 1,000 locations, the Financieele Dagblad reported in January.