The smell of diesel, I don’t even know why
Sprinklers/Hose water
The smell of that really cool and clean air that you often encounter near a coast. As a child we would every so often go on road trips down to the seaside in Brighton in the UK and I have very nostalgic memories of the ever-stronger, fresh sea air teasing our arrival at this place of sun and surf while on the motorway.
The smell of Play-Doh. I used to play with that stuff for hours on end.
Honeysuckle. Had them at my grandparents house and loved tasting the nectar.