John Tuttle asked about the smell of ozone.

Ozone is an allotropic form of the element oxygen.  Oxygen exists as
a gas in our atmosphere in the stable but reactive molecular form of
two atoms per molecule [O2].  If the oxygen molecule is excited by
external electromagnetic energy of a selected wavelengths, it can be
converted to ozone having three atoms per molecule [O3].

With little provocation ozone will spontaneously decay to the stable
two atom per molecule form plus nascent oxygen.  Nascent oxygen is
a spontaneous momentary state in which the very active (quasi
monomolecular) uncombined oxygen atom (called a radical) is seeking
to combine with anything it can find.

In our atmosphere at normal temperature and humidity, nascent oxygen
will combine with nitrogen gas to form a molecule called nitrous oxide.

Ozone is odorless.  The odor that most people identify as ozone is
actually the odor of nitrous oxide.

Ozone can be produced in the atmosphere using energy imparted by
ultraviolet light and also by electric discharge.  The most certain way
to create ozone is to use the discharge from a Tesla coil.  Scientific
supply houses sell handheld Tesla coils (for checking leaks in vacuum
glassware) for a reasonable cost.

If you go to all this trouble you can smell "ozone" first hand.
Now let's see if you can describe the odor.  I certainly can't.

Bill Finch