6.6 - Dangers of Electromagnetic Radiation

Why high-frequency EM radiation can harm the body

• Whether EM radiation is harmful depends on how much energy it transfers to living tissue.
• The higher the frequency, the more energy the radiation carries, and generally the more harmful it is.

Ultraviolet, X-rays and gamma rays are ionising

• These are types of ionising radiation: they carry enough energy to knock electrons off atoms, damaging living cells.
• Ultraviolet (UV) - Absorbed by the skin, where it damages surface cells. It can cause premature ageing of the skin, skin cancer, and eye damage including blindness.
• X-rays and gamma rays - Carry even more energy than UV. They pass through the skin and are absorbed by deeper tissues, damaging cells throughout the body and leading to mutations and cancer.

Visible light and radio waves

• Intense visible light - Can damage the eyes.
• Large doses of radio waves - Believed by some to cause health problems such as leukaemia, though this hasn't been reliably proven.

Protecting yourself from ultraviolet

Wear sunscreen with UV filters in strong sunlight, and limit time spent in it.

Lower-frequency hazards - Microwave and infrared

• Radiation doesn't have to be ionising to be harmful. Microwaves and infrared can damage the body by heating it.
• Microwaves - Have a similar frequency to the vibrations of many molecules, causing internal heating of body cells.
• Infrared (IR) - Absorbed by the surface of the skin, where high exposure causes skin burns.