Non-ionizing radiation is a category of radiation that does not have enough energy to ionize molecules or atoms. This inability is due to the low frequency and high wavelength of radiation waves. Radio waves, infrared, microwave, visible light and near ultraviolet are the only forms of this type of radiation. Though significantly less harmful that ionizing radiation, non-ionizing radiation can cause harm to living organisms such as human beings. Protecting oneself and others is not difficult.
All forms of electromagnetic radiation are photons that act like waves when traveling through space. When these photons come into contact with atoms, the atoms become more energetic by absorbing the photons. If the atoms gain enough energy, they release some electrons, ionizing the atoms. Though non-ionizing radiation transfers energy to recipient atoms, ionization never occurs.
In order of increasing energy, radio waves, microwaves, infrared radiation, visible light and near ultraviolet are the only forms of non-ionizing radiation. These forms of radiation are ubiquitous in the universe and are produced by many man-made sources such as radio broadcast towers, microwave ovens and light bulbs. The earth's atmosphere filters the majority of radiation from cosmic sources.
Non-ionizing radiation is much less harmful to living organisms than ionizing radiation. The breaking of molecular bonds produced by ionizing radiation can cause damage to DNA, leading to diseases such as cancer. Gamma radiation, the most powerful type of ionizing radiation, is released in high quantities during events such the detonation of a nuclear weapon. Though exposure to non-ionizing radiation is relatively much safer, side effects from short-term exposure can still cause health problems.
The physical effects caused by radio waves produced by cell phones or Wi-Fi antennas are negligible. Evens so, visible light, especially light produced by lasers, can cause corneal burn and retinal damage. This damage occurs due to the intensity of the light; it can cause permanent damage even after a short exposure. More powerful lasers, like those used in laboratory experiments, can quickly produce skin burns or other serious injuries.
As laser light is the only potentially harmful form of non-ionizing radiation, one needs to only follow a few simple rules to protect oneself and others. For example, one should responsibly use commercial laser pointers. One should never give a laser pointer to a child. If one works in a laboratory setting, following laboratory safety procedures and wearing protective eyewear will ensure that all experiments are conducted safely.