Used to identify items outside visible spectrum areas, known as 'black lighting'. Used to detect forged bank notes: they fluoresce in UV light real bank notes don’t. Used in state of the art air-handling units, personal air purifiers and swimming pool technology. UV synthesises vitamin D in skin, controls the endocrine system and is a painkiller. UVC is germicidal, destroying bacteria, viruses and moulds in the air, in water and on surfaces. Sanitary and therapeutic properties have a marked effect on architecture, engineering and public health and have done so throughout history. Sun exposure for the skin is best restricted to before 11am and after 3pm in the UK in summer months. There is a problem with current sunscreens which protect against skin burning from high UVB but give inadequate protection against free radical damage caused by UVA.ĭark skins are not necessarily safer from harm.
Body waves are of two types, compressional and shear. Surface waves usually have the strongest vibrations and probably cause most of the damage done by earthquakes. Over-exposure to UVA and B damages surface cells and eyes and can cause cancer. The two general types of vibrations produced by earthquakes are surface waves, which travel along the Earths surface, and body waves, which travel through the Earth.
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