more on labradors and spaniels. paul hammond, whose company i-canine is working with auburn to train and deploy vapor wake dogs explains why. >> we need a dog that fits into the public profile, the public will walk past and ignore as if it's a domestic pet. >> reporter: the dogs are being used in airports, on amtrak trains and by police departments, too. what is it about a dog's nose as compared to ours that they are able to pick up something like that? >> well, the dogs' olfactory system is 220 million scent cells compared to a human's five million scent cells. that gives you a real comparison. where we might be able to smell a woman's perfume walking by, the dog will not only smell the perfume but the clothes, the material she's wearing, the shower gel she washed with that