Perhaps the reason we don't see smoking related lung disease described as popcorn lung is that no-one associated the diketones/diacetyl in cigarette smoke with the flavouring related disease until e-cigs came along and started using the same flavourings.
On the other hand, perhaps actually inhaling tobacco smoke, or directly inhaling e-liquid vapours causes/can cause a totally different disease because of the more concentrated quantity that would be inhaled direct to the lungs, or that it gets heated to higher temperatures ....I don't know.
What is obvious is that we don't know the long term effects of these things, yet it is known that diketones are, in certain circumstances, dangerous to the health - so the better flavouring manufacturers are working on ones that are better suited to the e-cig industry rather than for food flavouring.
I get breathing problems with PG, but I can also get it quite severely from certain flavourings: vanilla was one of the first in two brands of pre-filled cartridge used with a cig size battery. Having moved on to larger batteries and tanks last March, I've since found that some vanilla/custards trouble me, whilst others don't. So when I find a custard or dessert/bakery type that gives me no problems, I tend to stick with it
I also know that some fruit flavours can actually produce diacetyl, and it's interesting that I do get problems with a number of fruit flavours: lime, apple, blackberry, blackcurrant etc.
Some e-liquid makers will state that they use no diacetyl, but as reading this link will show, some use acetyl propionyl instead, and that is considered 'less risky'. Also, acetoin can catalyse into small amounts of diacetyl.
Diacetyl - Colonel Booms Bang Bang Juice - UK E-Liquid
It's a complex subject, but one that concerns me
because I do get some problems with certain flavours. It seems to back up the need for caution.
The best e-liquid and flavouring suppliers will show test results per item (examples are Perfumers Apprentice and one called Vapor Bar. There'll be others.) That way, people can choose to either buy the ones with amounts of these substances, or avoid them. It's all about informed choice.
No different really to being able to read the ingredients of a food product, and avoid any not wanted, such as trans-fats or E numbers etc.
When I see a company cited as having particularly high levels of diketones from independent testing, it does make me tend to back off.
That's a clever idea! I don't use drippers, but can see how many will welcome that, particularly those that don't want to rebuild.
