When I use to have trouble with smells, I'd instantly "ground" myself in here-and-now to make sure they wouldn't go any further? Shift your focus to the room you're in or literally go outside and feel the cold/wind, etc. and see the cars driving in the street, etc. I use to get "snatched" back by smells; it was like someone grabbed me by the scruff of my neck and threw me back 40-50 years.