I am a nurse. As such, I have training in basic body processes. Before you continue, let me advise any with a poor constitution to bypass this blog entry. If you get queezy easily, don’t continue reading.
The olfactory sense is controlled in the brain with stimuli provided from the upper areas of the nose containing folds where particles interact and chemically stimulate responses which are interpreted by the brain to be certain scents. Smell is then provided by a direct interaction of a substance with the body, or in this case by particles entering the nose and touching the receptors there. That means the only way we know someone passed a “silent but violent” one is that the particles formerly in the rectum of that individual have passed into our nose and come into contact with receptors there. Have a nice day. Don’t hold your breath too long.