The conventional security screening equipment currently used in public places is safe for human health under normal passage conditions, and its radiation dose is much lower than the level that would cause harm to health, so there is no need to worry excessively.
Different types of security devices and their safety:
1. "Luggage X-ray security scanner" used in subways and stations
This is for checking personal packages, you won't come into direct contact with it.
Principle: Use X-rays to penetrate luggage and form images for security personnel to view.
Security: The protection of the device itself is very tight. Radiation only occurs in a sealed environment inside the lead curtain, and the amount of leaked radiation is negligible. According to the Chinese national standard (GB 15208.1-2018), the radiation level leaked during a single inspection shall not exceed 0.05 μ Sv (microsieverts). This dose is even much lower than the amount of cosmic radiation you receive during a 2-minute flight by plane. Therefore, it is safe to briefly touch the lead curtain when picking up and placing bags.
2. "Metal detection doors" at subway and station entrances
This is the security checkpoint you walked through.
Principle: Using electromagnetic induction to react with metal objects and trigger an alarm. It does not emit ionizing radiation (such as X-rays) and only generates a weak electromagnetic field.
Safety: Its electromagnetic field intensity is very low, even lower than the intensity of many household appliances such as hair dryers and razors during operation, and its impact on the body can be ignored. Pregnant women and pacemaker wearers can safely pass through.
3. Millimeter wave human body security screening devices used in airports and important venues
This is the device we detailed earlier. You need to stand still and raise your hand to receive the scan.
Principle: It emits millimeter waves with extremely low energy to the human body and forms an image by receiving the reflected waves.
Safety: Millimeter waves belong to non ionizing radiation, and their energy is very low, not enough to break the molecular bonds of human cells. It typically emits only one thousandth of the power of a mobile phone signal and has an extremely short scanning time (only a few seconds). Multiple authoritative health institutions around the world, such as the US FDA, have certified it as safe for the public, including pregnant women and children.
In summary, you can rest assured that the daily repeated security checks conducted for public safety will not cause harm to your physical health.
