Airport security scanners are generally considered safe for travelers due to minimal radiation exposure and adherence to strict regulatory standards.
Navigating airport security is a routine part of travel, and many wonder about the safety of the screening equipment. Understanding how these scanners work and their impact can help travelers feel more comfortable as they move through the checkpoint.
Understanding Airport Security Scanners
Airport security checkpoints primarily use two types of advanced imaging technology (AIT) scanners to screen passengers. These systems are designed to detect metallic and non-metallic objects concealed under clothing without physical contact.
Millimeter Wave Scanners
Millimeter wave scanners are the most common type found in airports today. They emit very low-energy radio waves, similar to those used in cell phones, which bounce off the body and create a generic outline image.
- This technology uses non-ionizing radiation, meaning it does not have enough energy to remove electrons from atoms or molecules, thus avoiding DNA damage.
- The energy levels are extremely low, often compared to the radio waves from a cell phone call lasting a few minutes.
- The scan typically takes only a few seconds, limiting any potential exposure duration.
Backscatter Scanners
Backscatter scanners use very low-dose X-rays to create an image of the body. While effective, their use has been phased out in many locations due to privacy concerns and the use of ionizing radiation.
- These scanners emit a very small amount of ionizing radiation, which has the potential to cause cellular damage at high doses.
- The TSA has largely replaced backscatter units with millimeter wave technology, citing privacy enhancements and public preference for non-ionizing systems.
- Any remaining backscatter units are subject to stringent safety standards and regular calibration.
The Science Behind Scanner Safety
The safety of airport scanners is primarily evaluated based on the type and amount of radiation emitted. Regulatory bodies set strict limits to ensure public safety.
Non-Ionizing vs. Ionizing Radiation
It is important to distinguish between the two types of radiation involved in airport security screening. Millimeter wave scanners use non-ionizing radiation, while backscatter scanners use ionizing radiation.
- Non-Ionizing Radiation: This type of radiation, found in millimeter wave scanners, microwaves, and radio waves, does not carry enough energy to break chemical bonds or damage DNA. Its primary effect at high levels is heating, but the levels in scanners are far too low to cause any significant temperature change.
- Ionizing Radiation: X-rays, used in backscatter scanners and medical imaging, carry enough energy to remove electrons from atoms, potentially causing cellular damage. The concern with ionizing radiation is cumulative exposure over time.
Radiation Dose from Scanners
The amount of radiation received from an airport security scanner is exceptionally small. For a millimeter wave scanner, the exposure is negligible, equivalent to ambient radio waves.
For a backscatter scanner, the dose is typically around 0.005 to 0.01 microsieverts (µSv) per scan. To put this into perspective, the average person receives about 3,000 µSv of natural background radiation annually.
| Source of Exposure | Approximate Dose (µSv) | Notes |
|---|---|---|
| Millimeter Wave Scanner | < 0.001 | Non-ionizing, negligible exposure |
| Backscatter X-ray Scanner | 0.005 – 0.01 | Ionizing, very low dose |
| Transcontinental Flight (US) | 30 – 50 | Cosmic radiation exposure |
| Dental X-ray | 10 – 20 | Targeted ionizing radiation |
| Chest X-ray | 100 | Diagnostic ionizing radiation |
| Annual Natural Background | 3,000 | From soil, air, food, cosmic rays |
Addressing Common Concerns
Travelers often have specific questions regarding scanner safety related to personal health conditions or cumulative exposure. It is helpful to understand the facts behind these concerns.
Pregnancy and Children
For pregnant individuals and children, the radiation dose from airport scanners is considered safe by health organizations. Millimeter wave scanners, which are now standard, use non-ionizing radiation, posing no known risk.
- The FDA states that the radiation exposure from backscatter X-ray systems is well below international and national safety standards.
- If a traveler prefers, they always have the option to request a pat-down instead of going through the AIT scanner.
Medical Implants and Pacemakers
Airport security scanners are designed to be safe for individuals with pacemakers, defibrillators, and other medical implants. The electromagnetic fields and radiation levels are too low to interfere with these devices.
- Metal detectors (walk-through magnetometers) use magnetic fields that are also generally safe for implants.
- If a traveler has concerns, they can inform the security officer and request an alternative screening method, such as a pat-down.
Privacy Considerations
Modern millimeter wave scanners use software that generates a generic, privacy-protective outline of a person. This outline highlights potential threat areas without displaying specific anatomical details.
- The images are not stored, transmitted, or printed.
- The software automatically processes the scan, and if no anomalies are detected, a “OK” message appears. If a potential anomaly is found, a generic indicator appears on the avatar, guiding security officers to the area for a targeted pat-down.
Your Choices at the Checkpoint
Travelers always have the right to request an alternative screening method if they prefer not to use the advanced imaging technology scanners.
Opting for a Pat-Down
If a traveler declines AIT screening, they will undergo a physical pat-down. This is a standard procedure and is conducted by a security officer of the same gender as the traveler.
- The pat-down is thorough and involves touching areas of the body, including sensitive areas, to ensure no prohibited items are concealed.
- Travelers can request a private screening area for the pat-down.
- A witness can be requested to observe the pat-down process.
When a Pat-Down is Required
Sometimes, a pat-down may be required even after AIT screening. This typically occurs if the scanner detects a potential anomaly that needs further resolution, or if a traveler opts out of AIT screening.
Security officers are trained to explain the reason for additional screening and to conduct procedures respectfully and professionally.
| Screening Method | Primary Technology | Radiation Type |
|---|---|---|
| Advanced Imaging Technology (AIT) | Millimeter Wave | Non-ionizing |
| Walk-Through Metal Detector | Electromagnetic Field | Non-ionizing |
| Physical Pat-Down | Manual Search | None |
Radiation Exposure: A Broader Perspective
Understanding airport scanner radiation in the context of other everyday exposures helps provide a balanced view of safety.
Natural Background Radiation
Everyone is continuously exposed to natural background radiation from various sources. This includes cosmic rays from space, terrestrial radiation from rocks and soil, and internal radiation from naturally occurring radioactive isotopes in our bodies.
- The average annual dose from natural background radiation is significantly higher than any dose received from airport security scanners.
- Living at higher altitudes or in areas with naturally radioactive soil can increase this baseline exposure.
Cosmic Radiation During Flight
Flying itself exposes travelers to increased cosmic radiation, as the airplane ascends above much of the Earth’s protective atmosphere. A single transcontinental flight can result in a radiation dose many times higher than that from an AIT scanner.
For frequent flyers, the cumulative dose from cosmic radiation during flights is a more significant consideration than the minimal exposure from security scanners.
Medical Imaging Comparisons
Diagnostic medical procedures like X-rays and CT scans deliver much higher doses of ionizing radiation than airport scanners. A single chest X-ray, for example, delivers a dose equivalent to hundreds of backscatter scanner screenings.
While medical imaging is medically justified, these comparisons highlight the extremely low-dose nature of airport security screening.
What the Experts Say
Major health and scientific organizations consistently affirm the safety of airport security scanners when operated within established guidelines.
- The World Health Organization (WHO) and the International Atomic Energy Agency (IAEA) endorse the safety standards applied to these devices.
- The National Council on Radiation Protection and Measurements (NCRP) in the United States has also evaluated the systems and found the doses to be negligible.
- Government agencies responsible for public health and safety, such as the FDA and the Centers for Disease Control and Prevention (CDC), monitor and regulate these technologies to ensure they meet stringent safety requirements.