Compositions for and methods of controlling olfactory responses to odorants

A method of increasing olfactory response to an odorant, the method comprising:

• providing a suspension comprising a solid dispersed phase of zinc metal nanoparticles consisting of from 40 to 300 atoms of metallic zinc per nanoparticle;
• applying the suspension to a surface that is proximate an odorant;
• and
• sniffing the surface, thereby nasally inhaling the odorant and the zinc metal nanoparticles, wherein the zinc metal nanoparticles react with olfactory receptors in the nose to increase olfactory response to the odorant.

A method of increasing olfactory response to an odorant, the method comprising:

• providing a suspension comprising a solid dispersed phase of zinc metal nanoparticles having a particle size in the range of from 1 to 2 nanometers;
• applying the suspension to a surface proximate an odorant;
• and
• sniffing the surface, thereby inhaling the odorant and the zinc metal nanoparticles through the nose, wherein the zinc metal nanoparticles react with olfactory receptors in the nose to increase olfactory response to the odorant.