[SAM] What do you think is better at finding a hidden bomb, this, or one of these?
[ANIMATOR]
All right it's Tuesday, January 19th, day before the inauguration... my bike just fell over again.
[SAM] One of the reactions animators was recently biking around Washington, DC, instead of doing his
job, and spotted what we're pretty sure is some sort of bomb sniffer—a device that tests the
air for molecules that could be coming from an explosive. It's like an electronic version of a
bomb sniffing dog. He might not have even noticed it had we not been working on a video about this
exact thing right before the pandemic. We'd heard rumors that some of the bridges around DC
had these sniffers on them that would notify police if someone was trying to sneak a bomb
into Washington. We had zero understanding of how these things might work, or if it was even
possible to detect bombs from that far away, but we decided, what the heck? Let's go look for some.
You're filming this. Hello!
Remember back when we could walk around without masks?
So I'm looking to see if I can see anything that's not just obviously a metal bridge.
I'm hoping that that pipe doesn't need to carry anything important.
I'm not seeing anything. Definitely nothing obvious. I mean I see stuff hanging, I see stuff
hanging under the bridge. [HILARY] You do?
[SAM] Yeah I saw a couple that looked like, it looked like bells. Right there,
there's something there. I don't know what it is, but it's something.
We realized that it's hard to find something when you have no idea what you're looking for so we
went to the experts. This is the US Naval Research Laboratory in Washington, DC, where chemists work
with detection dogs as well as explosives trace detectors, also known as electronic sniffers.
There we met chemists Dr. Lauryn DeGreeff and Dr. Braden Giordano. But the day's VIP was Eddie,
the very sweet detection dog. Dogs are known for being able to sniff out different scents,
but how do they actually do that? Dogs have cells deep in their noses called olfactory sensory
neurons. Each of those cells has multiple receptor proteins that stick out from the cell's surface.
When a dog sniffs it's taking a little sample of the hundreds, or thousands of different volatile
chemicals dispersed in the air, which could be coming from a fire hydrant, neighborhood trash,
or a bomb. Some of those compounds bind to the receptor proteins, causing the
receptor protein to change shape, triggering an electrochemical signal to the dog's brain,
which interprets a smell. Humans have the same basic system but there are a couple of
things about a dog's nose and nasal cavity that make it ideal for detecting smells.
[DR. DEGREEFF] The canine olfactory system is set up a little bit differently than humans. For one
they can breathe and smell as separate processes, so those chambers in their nose and behind their
nose are separated, so they can be breathing and sniffing and processing odor at the same time.
When dogs sniff out they sniff out very frequently and if you've ever looked closely at a dog's nose
they have the little slits on the side of their nose, so when they blow out the air blows back
and when it blows back it actually entrains, or pulls air from in front of it towards a
dog's nose so they get a bigger sample, something that humans certainly don't do.
[SAM] Right, right that's really cool.
Eddie can actually detect around 38 different explosives.
[DR. DEGREEFF] Now that he's already trained in the act of detection,
so he already knows how to do detection work, you can train him on a new odor in a matter of hours.
[SAM] I decided to put him to the test with some smokeless powder in a training aid
delivery device, or TADD. Smokeless powder is a common ingredient in
pipe bombs, and a lot of other homemade explosives.
Okay, so this is—
[DR. DEGREEFF] Still has sand on it.
[SAM] Oh it's just a little sand from the last training. I'm going to take this smokeless
powder that's in this TADD, and I'm gonna hide it, and see if Eddie will be able to find it.
Where should I go? I buried it a few inches under the sand.
I was excited to see how he'd do. Let's see what happens.
He got it.
Next Dr. Degreef showed me this mixed odor delivery device or MODD, that she developed
to train dogs to sniff out explosives. You can put up to four different chemicals into the MODD
and each has its own chamber. So the dog is able to smell the combination of chemicals in a bomb,
but because they're kept separate you're not actually making a bomb. Dr. Degreeff
took us to try out the MODD and see Eddie in an indoor situation he'd be more likely
to encounter in real life. Come here. Oh you are so cute. We hid MODDs around an
empty office of cubicles. I put the MODD with smokeless powder in one of the trash cans,
and Dr. Degreeff hid empty control MODDs around the rest of the office.
It did not take Eddie very long to find the smokeless powder. He's good at his job. But
if an electronic sniffer can do the same thing in human hands that's a pretty powerful tool.
Electronic sniffers work similar to a dog's nose in that they are detecting volatile compounds.
[DR. GIORDANO] This is sampling a vapor, just like the dog is,
it's sniffing. In this case it has a pump.
[SAM] Electronic sniffers can take samples from the air directly or use a swab.
Either way the compounds are drawn through a glass tube that's coated with molecules that
interact with certain targets, say explosives like tnt or tatp. When they do interact the
molecules will fluoresce, or light up. Light sensors in the sniffer detect that fluorescence,
and then tell you whether the target molecule is there. Now, with a quick training session,
it was my turn to be put to the test. One of the researchers at the lab hid the sample
for me to detect and I was off. Let's see how this goes. Start over here. Six, five, four,
It was not quick. No threat detected. I'm gonna... okay.
Eddie won this round because, well electronic sniffers like these are not designed to do what
I did here: find buried explosives or find them in a big open room. That's where dogs have a major
advantage. They can quickly move around until they pick up on a scent. Electronic sniffers
are designed for smaller spaces like a bottle or a box, or to be used with swabs, like what TSA
does when you're selected for extra screening, and they have some distinct advantages over
Eddie. You can have a bunch of them, they don't take hours and hours of training like dogs do,
and the technology is only getting better. Right now a combo of dogs plus electronic sniffers
is our best bet at detecting bombs. As for the electronic sniffers on bridges around DC, we're
still looking. If you've heard this same rumor or know someone who has some intel, let us know.