Airport Testing: Who, What, And Where?

Airport security measures are a mandatory part of flying and have been a topic of discussion and controversy over the years. While there are varying opinions on the extent to which people should be tested at airports, it is clear that security measures are in place to keep us safe.

Full-body scanners, for example, are used to detect threatening items and contraband such as weapons, explosives, and drugs under multiple layers of clothing. While some people may feel that this is an invasion of privacy, others argue that it is a necessary safety precaution.

Additionally, there are other security measures in place, such as liquid restrictions, swabbing for explosive traces, biometric identification, and sniffer dogs.

As technology advances, we can expect to see even more innovative security measures implemented at airports worldwide.

Full-body scanners

Backscatter X-ray scanners use low-dose radiation to detect objects hidden under clothing or in body cavities. The dosage of radiation received is usually between 0.05 and 0.1 μSv, and there has been considerable debate regarding the safety of this method, leading multiple countries to ban their usage.

Millimetre wave scanners, on the other hand, use non-ionizing electromagnetic radiation similar to that used by wireless data transmitters. They produce a 3D image of the subject and do not emit any radiation dose, as the energy directed towards the subject is not sufficient to damage cells, DNA, or other atoms in the body.

However, there have been concerns about the privacy and health implications of full-body scanners. Some passengers have objected to images of their naked bodies being displayed to screening agents or recorded by the government, calling them a violation of basic human rights and privacy. In response, newer scanners now use privacy software that generates a generic avatar image of the human anatomy, ensuring privacy while maintaining security effectiveness.

Additionally, there have been questions about the safety of backscatter X-ray scanners, with critics arguing that the radiation emitted may pose health risks, especially for frequent travellers. As a result, some countries, such as France and Germany, have banned their use.

Biometric identification

The TSA's exploration of biometric technologies is grounded in scientific advancements, aiming to improve accuracy, speed, and automation. One key focus is on facial matching, where a camera takes a passenger's picture and compares it to the image on their photo ID, such as a passport or driver's license. This approach does not require a database of pre-staged images, as it relies on real-time comparisons. Additionally, the TSA is evaluating the impact of digital identity documents on aviation security and operations, particularly in response to the COVID-19 pandemic.

The U.S. Customs and Border Protection (CBP) has successfully implemented facial biometrics at all international airports for entry processes and 55 airport locations for exit processes. This technology, known as Simplified Arrival, enhances security and improves the traveler experience by utilizing touch-free technology that streamlines entry procedures. To date, CBP has processed over 540 million travelers using biometric facial comparison technology and prevented more than 2,000 impostors from entering the United States.

The CBP's implementation of biometric technology stems from the 9/11 Commission Report, which authorized the use of an automated system to record the arrivals and departures of visitors at all air, sea, and land ports. Facial comparison has proven to be one of the most effective solutions, offering an extra layer of security and a more touch-free experience for travelers. The CBP's Traveler Verification Service (TVS) matches live images of travelers with existing photo templates from their travel documents, ensuring efficient and secure identity verification.

Liquid restrictions

Most airports around the world restrict the amount of liquid you can take through security in your carry-on luggage. This is due to a terror plot that was foiled by the Metropolitan Police in 2006. The plot involved bringing down at least seven transatlantic flights using liquid explosives concealed in 500ml soft-drinks bottles.

In the UK and across the EU, the current restriction is that travellers can carry up to 1 litre of liquid, which must be split across containers holding no more than 100ml of liquid each. These containers must be placed inside a clear, resealable plastic bag measuring approximately 20cm x 20cm, and they must be removed from your hand luggage to be scanned at airport security.

In recent years, some airports have been testing new 3D scanners, which use advanced x-ray technology to create layered 3D images that security staff can tilt and rotate to better identify the contents of cabin baggage. These scanners were expected to remove the need for liquid restrictions, but they have had higher-than-expected rejection rates, resulting in security officers having to search cabin baggage by hand. Due to this issue, the 100ml liquid restriction was reinstated across all UK airports in June 2024, and across EU airports in September 2024.

It is unclear when the liquid restrictions will be lifted, as authorities have not provided a timeline for addressing the technical issues with the new scanners.

Trace detection with swabbing

Passengers are selected for swabbing based on several factors, including suspicious items in their baggage, behavioural cues, refusal of full-body scanner screenings, random selection, travelling with pets, and medical equipment. The process is relatively quick, but it can be stressful for passengers. While the test is not foolproof and can produce false positives, it improves the overall safety of air travel.

The swab is analysed using ion mobility spectrometry (IMS), which transforms the sample into gas particles. These particles are then moved through a tube via an electric field, and a detector records their transit time. The results are compared to a library of known substances to identify any matches. If a match is found, the ETD machine will beep and light up a red light.

Common substances that can trigger false positives include glycerin, found in lotions, makeup, and soaps; medications such as nitroglycerine pills; and exposure to firearms and ammunition. If a passenger tests positive, they may be subjected to further testing, including pat-downs and thorough baggage inspections.

Sniffer dogs

Detection dogs are trained to identify individual scents even when they are masked by other odours or tightly sealed. They can detect substances within luggage and on a person. The dogs work silently, without barking or making a sound, to alert their handlers when they have found something.

The most common breeds used as detection dogs include Belgian Malinois, German Shepherds, Dutch Shepherds, Doberman Pinschers, Rottweilers, and Labrador Golden Retrievers. These dogs are chosen for their intelligence, energy, and loyalty, as well as their ability to work well in crowded spaces.

In addition to security, detection dogs can also be used for therapy to help passengers de-stress while waiting for their flights. They can also be used to reunite passengers with lost items, as in the case of Sherlock, a sniffer dog hired by KLM to help passengers find their lost mobiles and valuables.

Frequently asked questions