I have been very sad about my friend dying horribly recently.
Aww Memaw came to hug me then. It makes sense now. I couldn't trace the smell anywhere else. My brother thought I spilled something or sprayed some scented febreeze but I haven't been home since morning.
I hope it's not that other explanation about brain issues lol.
I've also heard that the pervasive smell of flowers when there's no one around is the spirit of a loved one in your presence, especially if that scent has some particular link to the person who has passed on.
For example, if your grandmother loved lavender cologne and wore it often, then it might be her way of connecting to you and letting you know that she's with you.