The Nose Knows

Anatomically, a dog nose is quite different from a human's which is why they are able to smell things we cannot. I once had dog scenting explained to me like this and its how I often explain it to others. If a human walks into a house where beef stew is cooking on the stove they say "Yummy beef stew!". If a dog walks in to that same house they think "yummy carrots, onions, beef, water, garlic etc" and no matter how many hours that dog stays in that house as long as the beef stew is cooking on the stove they can smell each individual part. All we are training our alert dogs to do is let us know when they smell two specific scents-the high scent and the low scent.
So what affects the scent?
-airflow/currents/wind help if they are moving from you to your dog
-scenting is easier in cool wet weather then hot and dry
-scenting when the dog is really hot is hard because when a dog pants they breathe through their mouth so not as much scent gets to their nose
-lotion, perfume etc does not affect scent (see beef stew story above)
-some medications can affect scent but most do not(I'm on quite a few and Lucy's doesn't have a problem)
-dogs can scent underwater. they have a Jacobsen organ then humans lack which allows them to do this.
-your movement helps the dog pick up the scent. I've noticed if Lucy is laying next to me for a while it sometimes takes a little longer to pick up the scent but, if I stand up and walk past her she immediately stands up to alert if my blood glucose is off.


I'm sure they are more but this is all I know so far.