That means that just five doses of a metered inhaler would have around the same carbon emissions as a 14km car trip.
The inhalers contain around 100 doses each, meaning each inhaler is emitting the carbon equivalent of a 290km car trip, according to Nice.
In comparison, inhalers containing dry powder, contain just 20g of carbon dioxide per does, and provide good results for most patients.
Professor Gillian Leng, deputy chief executive of Nice, said: "People who need to use metered dose inhalers should absolutely continue to do so
"But if you have the choice of a green option, do think about the environment.
"Cutting carbon emissions is good news for everyone, especially those with respiratory conditions."
Nice urges patients to return used inhalers to local pharmacies so that they can be safely disposed of, or to recycle them where possible.