I hope you don't suffer from Anosmia. That's the condition that is associated with loss of the sense of smell. That would be a shame, for many reasons, but chiefly for me, that trigger which brings back memories from, say, 50 years ago. They even have a name for that; it's called The Proust Effect.
Overwhelmingly these memories centre around school: warm milk, burning bakelite (every thing electrical hummed and got hot), biscuits, cloth, wood, polish, jeyes fluid, wax crayons, sweet shops, stale clothes that were once washed in Surf or Omo or Oxydol powder. Almost anything can trigger those memories of one little, very confused young boy who sometimes forgot his hanky or peed his pants or stared blankly at the blackboard and stared down at olfactory nightmares - school dinners - the enforced eating of which these days would be classed as child abuse. That smell always lingered well into the afternoon and got steadily worse. It is not so long ago that schools still smelt the way they did back then in the late fifties and early sixties. It quite unsettled me to be met by the same aromas when visiting my kids' school, to be jolted into a different reality that had mysteriously shrunken in size and scale.
One of my favourite smell scenarios, and it still is, is the smell of railway stations - particularly Kings Cross. The aroma of diesel combined with a kind of acrid, metallic top-note, and that black, sticky stuff you see all over the rails and sleepers (God knows what it is), wee wee, sick and coffee, presented with a flourish, a huge rush of air that whistles through the galleries and corridors. The reason for this is very simple; it was a portal to another world, the the world that enabled me to leave behind my tiny, parochial backwater town with its shut-down mentality and discover something breathtakingly challenging and other. It was a portal to my coming of age.
Many olfactory sensations we shall never get back. Tobacco smoke is one which permeated almost every aspect of life until it was banned. Remember the French Underground? Gitanes! And Disque Bleu!