R134a, R134, HFC134a are interchangable names used by the refrigerant industry to describe tetrafluoroethane. HFC134a is actually a descriptive name (HydroFluoroCarbon) the numbers indicate the quantity of hydrogen, fluorine, carbon atoms in the molecule according to a numbering scheme that industry has agreed upon. R22 is actually HCFC22 not HFC22 as often quoted in airsoft circles.
The fine for uncontrolled release does apply to refrigerant packaged R134a. I suspect that this is a legal holdover to prevent the release of R12, and R22 which are both phased out for ozone depleting reasons. While it isn't ozone depleting, R134a does have a high global warming potential (about 1300x higher than for CO2 IRC) so restrictions on it's large quantity release will probably not be removed.
I think the amounts of non refrigerant packaged R134a are so small in comparison to refrigerant purpose R134a that aerosol release is not regulated. Especially considering the immense global warming potential that automobiles represent. Restricting computer duster R134 is like going after the electronics industry for lead solder when improperly disposed lead acid batteries account for well over 80% of the lead content in garbage dumps.
If I had the time to chase the appropriate figures down, it may be that the global warming output for steel refining and manufacturing, and transportation of a duster can could exceed the GWP of the R134 that would be stored inside. It's funny how accounting figures end up sometimes.
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