Before it derails in two distinct yet off-topic directions: we're not supposed to discuss materials safety in the product threads anymore, but I have a line on my todo-list since a few days to create a dedicated discussion thread somewhere more appropriate, as it concerns a lot of recent models and most notably nearly all "instant on-demand convection" devices.
Meanwhile don't worry, the guys on that very same site I listed tried to assess the impacts and concluded that, at least in the e-cig case, the exposure levels are well inside the approved rates/quantities and should not be a concern. But that doesn't mean it shouldn't be studied nor at least discussed, as the particulates are there, whether in safe levels or not.
PS: and yes it matters, especially Nickel, as some people have sensitivities or even allergies to it
PS2: for the second off-topic direction, you guys have made your point(s) about the VapeCritic, we got it, now let's move on