hahaha, i love your toxic smell whiff thing, i can just imagine them puffing toxic smell all around! they don't have that, thank god!
i do find that newborn babies smell different for the first few weeks, i think it's a combination of milk and things that normally are not present.
eight months old and given you've not noticed it before, i'd go have it checked out. what does it smell like? sweet? fruity? have you checked her lady bits, sometimes they can get a smelly discharge there - if you find that's what it is, you need to take her to the vet straight away.
i would generally recommend to take a chin to the vet if you notice any change, either physical or behavioural - they are good at hiding things and it's very difficult to tell there's something wrong until it's too late.