There are two general categories of
properties that are used to describe materials:
chemical properties and physical properties.
Chemical properties describe chemical changes of
matter, i.e. changes that result in changes to
composition of matter. Some examples are
flammability, acidity, and oxidation
contrast physical properties are characteristics
that can be measured without changing the chemical
composition of the matter. These include mass,
length/shape measurements, and phase
transformation temperatures (e.g. boiling and
melting points). Next, consider
what "makes" an odor .
Basically, molecules of the matter in the air
dissolve into mucus and eventually bind with
(physically fit into) smell receptors. All of
these are physical changes though; none are
related to a change in composition. Thus, odor is
not a chemical property, but rather is a physical
property. That being said, a new odor
detected can be an
indication of a chemical change which
the formation of a new substance (one with a
different associated odor).
[All of this is in contrast with the ScienceLine
here, but those answers give essentially no
discussion of the differences between chemical and
physical properties or of odors.
These answers give more background on odors, but
not chemical vs. physical properties.]