Hazards of electromagnetic radiation
Over-exposure to certain types of electromagnetic radiation can be harmful.
The higher the frequencyThe number of waves produced each second. The unit of frequency is hertz (Hz). of the radiation, the more energy it carries and the more damage it is likely to cause to the body:
- radio waves: one of the few known effects of radio waves on the human body is a very small rise in temperature of up to 0.2 oC. Some people claim the very low frequency radio waves from overhead power cables and mobile phone base stations near their homes has affected their health, although this has not been reliably proven;
- microwaves can cause internal heating of body tissues;
- infrared radiation is felt as heat and causes skin to burn;
- visible light from a laser which is very intense can damage the retina at the back of the eye;
- ultraviolet can damage skin cells and lead to skin cancer and damage the eyes, it can cause skin to age prematurely;
- X-rays damage cells inside the body. They cause dangerous ionisationProcess by which electrons can be added or removed from an atom to create an ion. and when this happens with moleculeA collection of two or more atoms held together by chemical bonds. in living cells, the genetic material of a cell, the DNAThe part of the cells of living things that carries information about how they look and function. Everyone鈥檚 DNA is different, except identical twins who share the same DNA. is damaged. This can lead to cancer. This is why doctors and dentists stand behind protective screens when taking lots of X-rays;
- gamma rays also damage cells inside the body causing dangerous ionisation in living cells which damages DNA. This can lead to cell death and cancer.
Ultraviolet radiation and suntan
Ultraviolet radiation - UV - is found naturally in sunlight.
We cannot see or feel ultraviolet radiation, but our skin responds to UV exposure by turning darker over time.
This is called a sun tan.
This happens as our bodies attempt to reduce the amount of ultraviolet radiation reaching deeper skin tissues.
Darker skins absorb more ultraviolet light, so less ultraviolet radiation reaches the deeper tissues.
This is important, because prolonged exposure to ultraviolet radiation can cause skin cancer and damage to eyes.
It is sensible to wear high protection, UV blocking sunscreen on sunny days to avoid skin cancer.
Overexposure of our eyes to ultraviolet radiation can cause blindness, so we should also wear hats and sunglasses on sunny days.