Well it points out that we are inhaling PG\AG, relatively benign substances, in a new and novel way.
However, although the risks are negligible it would be nice to actually prove its safe which this paper did not directly address.
But it did address any concerns to do with metal and other contaminants
and also passive vaping.
I am certainly not concerned myself about PG/AG, but its always good to be informed.
I would agree, but I do think that regulation is a precaution that should be seriously considered, if nothing else than to ensure and maintain quality of product.