Truth behind airport security swab tests and what they do | Travel News | Travel

After one woman was “thoroughly questioned” at the airport, she took it upon herself to clarify to her followers what a swab test is “actually doing” when you’re passing through security.

Caroline Steel, who boasts a background in science, asked her followers whether they had ever been swabbed at an airport, explaining that there is a very good reason why staff carry out the procedure, and it all comes down to the safety of passengers on planes.

She revealed that they can “pick up tiny traces of what you’ve been handling, which are analysed there and then”.

This means that if you’ve been involved in anything suspicious, security staff will be able to investigate further – but sometimes there are errors.

Caroline, who presents CrowdScience on the BBC, also disclosed that she recently received a “false positive” prior to boarding a flight. Intrigued by how the process works, she decided to delve deeper into the subject.

The scientist explained that they are searching for “tiny traces of explosives,” which can be “even lighter than one trillionth of a gram”.

She explained: “So the fabric is rubbed over things like your hands and your bag, and it picks up microscopic particles.

“It’s then put inside […] an ion mobility spectrometer. Inside the particles are heated, turning them into a gas, and then they’re given a charge, which turns them into ions.

“The ions then move through a tube which has an electric field across it. And the ions move at different speeds through the tube, depending on their mass, their shape, and their charge.”

The device measures “how long it takes for each ion to move through the tube”. This is then “compared to a database of known substances”.

Should something travel at the “same speed as a suspicious compound, like an explosive, then the machine raises an alert”.

However, as Caroline discovered, this does not necessarily indicate that you are transporting anything suspicious. This is owing to the fact that “sometimes harmless substances can look similar to explosive substances”.

Should this occur, you “just get further checks,” so there is little cause for concern.

In the comments section, one user wrote: “I actually always thought it was for drug testing, but explosives do make sense for an airport”.

Another remarked: “Happens to me just about every single time I fly and I’ve no idea why, always me out of 4-12 people I’m with”.

Meanwhile, a third user shared: “I’ve been stopped nearly every time since having kids. One of the guys there told me some baby wipes set them off. Always have wipes in my bag, so it makes sense”.