Over at the The Volokh Conspiracy Orin Kerr notes that the Supreme Court has reaffirmed that getting sniffed by a police dog does not constitute a search under the Fourth Amendment. I wonder how this will play out if technology replaces the dogs?
There exists an emerging class of chemical detectors for which the best description is artificial noses. Like biological noses, these devices can detect a wide range of compounds wafting in the air. Some designs even use biological receptors embedded in microchips. Within 10 years or so these detectors will reach the level of sensitivity of a dog’s nose and they will fit in a handheld unit. Unlike a dog, these devices will be able to tell us exactly what they detected and in what amounts.
Let’s call these devices eSniffers. Their existence raises all kinds of interesting legal and cultural questions. For example, at what point does the use of an eSniffer become a search under the Fourth Amendment?
Each human being has a unique chemical signature, a scent. We shed our chemical signature as we move around, and its traces remain for hours or days, depending on environmental conditions. Dogs and other animals use this signature to identify individuals. A sufficiently advanced eSniffer could do the same. Moreover, an eSniffer could permanently store an individual’s signature electronically. Our individual scents would become as identifiable and as accessible as our fingerprints.
There are many possible uses for eSniffers in law enforcement. An eSniffer could record which individuals were in a certain area or whether they touched certain objects. Law enforcement could use an eSniffer on a fresh crime scene to record all of the signatures and then go looking for people who match them. Would a cop’s walking down the street with an eSniffer, sniffing each person he passed, constitute a search? What about eSniffers embedded in buildings like metal detectors, checking everybody who passes through?
It doesn’t stop at identifying and tracking individuals. The Law could also use eSniffers to go on fishing expeditions. Traces of drugs, illegal and otherwise, get secreted by the skin and respiration. In principle, an eSniffer could tell if a person used an illegal drug recently, by detecting this secretion in the air. Would an individual’s setting off of an eSniffer in a public area be grounds for suspecting that individual of illegal drug use? At present, being singled out by a drug dog is sufficient in most cases. If every cop carried an eSniffer that might change.
eSniffers might also raise other privacy concerns. Many diseases produce their own scent signatures, and a person with an eSniffer might be able to learn something about your medical condition (and what medicines you take) just by walking by you. Birth control pills alter a woman’s scent and that could be detected as well. Somebody could also tell what you recently ate or drank.
Compared to most animals, humans have a very weak sense of smell. Culturally, people in developed nations have developed an aversion to smell bordering at times on a phobia. We ignore scents whenever possible. Our legal and cultural concepts of privacy don’t currently deal with scent to any significant degree.
eSniffers are going to force us to change that.