Reference point
Walk past a metal workshop where welding is going on, smelling from a distance.
Do this before you read on. An entry only works when you have just smelled the thing.
Sharp, metallic, with a scorched note and a strange layer that has no common name.
That strange layer is ozone, and it is one of the few purely inorganic smells in this dictionary. Nothing organic, nothing biological.
It is also extremely short-lived. A few metres away it is gone completely.
How to smell it
Stand well back and walk past rather than stopping — the welding arc gives off ultraviolet light that harms the eyes. Smell as you pass, remember it, then move on.
Why this one is hard
Because there is no word. People usually call it “welding smell” or “electric smell”, both naming the source rather than describing the quality. This is a place where vocabulary is genuinely lacking.
Don’t confuse with
This entry
Electric welding
Smoky & Mineral family
Welding gives ozone — sharp and cold. A match gives sulphur dioxide — scorched and warm. Two different inorganic gases.
Scientific note
An electric arc splits oxygen molecules, which recombine into ozone. The human nose detects ozone at very low levels, about ten parts per billion, so you smell it at concentrations still far from harmful. The same compound forms in thunderstorms and gives the sharp note before rain.
In Vietnamese life
Small metal workshops scattered among homes are a feature of Vietnamese cities. The smell of welding is therefore a smell of the street rather than of industrial zones, and it usually comes with the sound of a cutting machine.