The American government has banned the use of CFCs (chlorofluorocarbons) in all kinds of household products from aerosols to refrigerators.
They have done this because of the damage to the ozone layer caused by these chemicals.
They have opted to mandate companies make use of HFA’s (hydrofluoroalkane) which do not carry the ozone damaging properties of CFCs.
Unfortunately this gas is also considerably more expensive than CFC.
This is also a concern to asthma sufferers because now asthma related inhalers can also not contain CFCs and must now make use of HFA gases. The gas is used to propel the liquid with a small amount of force into the mouth in aerosol form.
The new style inhalers with HFA are considerably less powerful than the old CFC versions.
Some asthma advocates and patients are questioning if the new gas propels sufficient quantities of drugs into the bodies system.
There is also anecdotal evidence that the priming of the device has to be extremely precise in comparison to the CFC versions.
And furthermore that they require a more thorough and more frequent cleaning of the device in order to ensure accurate use.
The whole problem boils down to the fact that the CFC propellant was simply more powerful and therefore forced drugs more efficiently into the throat and also were relatively self cleaning because of the higher pressure used.