WEBVTT 00:00:10.411 --> 00:00:14.000 Although UV rays are invisible, 00:00:14.000 --> 00:00:17.000 they are not harmless to human beings. 00:00:17.000 --> 00:00:21.000 They can cause various types of damage to the skin and eyes 00:00:21.000 --> 00:00:23.000 since they involve high-energy radiation. 00:00:23.000 --> 00:00:26.000 When we spend time in direct sunlight 00:00:26.000 --> 00:00:29.321 we are particularly exposed to UV radiation. 00:00:29.321 --> 00:00:32.165 But even being outside on a cloudy day 00:00:32.165 --> 00:00:35.227 exposes us to some UV radiation. 00:00:35.227 --> 00:00:39.462 One guide to how severe the radiation is on a specific day 00:00:39.462 --> 00:00:42.000 is provided by the UV index. 00:00:42.000 --> 00:00:46.105 A high UV index means that UV radiation intensity levels are high. 00:00:46.105 --> 00:00:50.230 It will then take less time for unprotected skin to suffer sunburn 00:00:50.230 --> 00:00:52.911 or the eyes to be damaged. 00:00:53.435 --> 00:00:57.272 Skin and eye cells absorb the UV radiation 00:00:57.272 --> 00:01:00.000 and are affected by the rays. 00:01:00.000 --> 00:01:02.000 UVB radiation prompts the epidermis 00:01:02.000 --> 00:01:06.000 to produce the pigment melanin. 00:01:06.000 --> 00:01:11.000 The outcome of this process is visible after a few days as tanning. 00:01:11.000 --> 00:01:15.337 UVA radiation is responsible for the darkening of pre-existing melanin. 00:01:15.337 --> 00:01:18.000 When the body is exposed to UV over longer periods 00:01:18.000 --> 00:01:20.000 cell division in the skin increases 00:01:20.000 --> 00:01:23.000 and its protective outer layer thickens. 00:01:23.000 --> 00:01:25.063 Although this natural UV protection 00:01:25.063 --> 00:01:28.587 delays onset of visible sunburn 00:01:28.587 --> 00:01:32.000 it does not prevent long-term cell damage. 00:01:32.000 --> 00:01:34.478 Skin is divided into various skin types 00:01:34.478 --> 00:01:37.000 depending on its capacity to protect against UV rays. 00:01:37.000 --> 00:01:39.000 People with a fair skin type 00:01:39.000 --> 00:01:41.000 can suffer UV damage 00:01:41.000 --> 00:01:45.000 after just 5 to 10 minutes in strong sunlight. 00:01:45.000 --> 00:01:50.962 This is due to an inflammatory reaction in the skin (similar to a burn) 00:01:50.962 --> 00:01:53.116 caused by the UV radiation. 00:01:53.116 --> 00:01:56.000 This leads to sunburn. 00:01:56.000 --> 00:02:00.000 UV rays can also damage eyes. 00:02:00.000 --> 00:02:02.519 This may take the form of temporary conjunctivitis 00:02:02.519 --> 00:02:04.379 or corneal inflammation. 00:02:04.379 --> 00:02:08.000 The latter is a type of sunburn of the eye. 00:02:08.000 --> 00:02:12.017 Apart from the damage due to burns caused by intense UV radiation 00:02:12.017 --> 00:02:15.413 even small doses of UV radiation 00:02:15.413 --> 00:02:18.000 can alter the genetic material in the cells. 00:02:18.000 --> 00:02:21.177 The body’s own repair mechanism 00:02:21.177 --> 00:02:24.310 can repair damage to the genetic material. 00:02:24.310 --> 00:02:28.000 However, frequent exposure to high UV radiation 00:02:28.000 --> 00:02:31.000 and recurring bouts of sunburn 00:02:31.000 --> 00:02:33.882 can lead to irreversible damage. 00:02:33.882 --> 00:02:36.000 Permanent changes occur 00:02:36.000 --> 00:02:40.000 that may develop into skin cancer over a lifetime. 00:02:40.000 --> 00:02:43.000 Intensive, prolonged exposure to UV radiation 00:02:43.000 --> 00:02:48.095 can also cause opacity of the ocular lens in the long term (cataract, gray star) 00:02:48.095 --> 00:02:53.158 as well as visual impairment and other eye diseases. 00:02:53.158 --> 00:02:57.000 The German Federal Office for Radiation Protection (Bundesamt für Strahlenschutz – BfS) 00:02:57.000 --> 00:02:59.918 recommends the following protective measures 00:02:59.918 --> 00:03:03.000 if the UV index is higher than 3: 00:03:03.000 --> 00:03:07.000 • avoiding strong sunlight, particularly around midday 00:03:07.000 --> 00:03:09.558 • protecting parts of the body that are exposed to the sun 00:03:09.558 --> 00:03:12.223 with clothing and head coverings 00:03:12.223 --> 00:03:16.000 • using sunscreen with UVA and UVB filters 00:03:16.000 --> 00:03:18.348 • protecting eyes with sunglasses 00:03:18.348 --> 00:03:23.159 tagged as “UV 400” or “100% UV protection” 00:03:23.159 --> 00:03:25.355 These protective measures are particularly important 00:03:25.355 --> 00:03:29.000 for people who work outdoors and children. 00:03:29.000 --> 00:03:32.075 Children’s skin is more sensitive than adults’ 00:03:32.075 --> 00:03:35.000 and is therefore particularly susceptible to sunburn. 00:03:35.000 --> 00:03:36.825 Studies also show 00:03:36.825 --> 00:03:39.973 that many cases of skin cancer in adults 00:03:39.973 --> 00:03:42.890 were caused by damage from the sun in childhood. 00:03:42.890 --> 00:03:44.859 In short: 00:03:44.859 --> 00:03:48.468 • UV rays from the sun can damage the genetic material in cells. 00:03:48.468 --> 00:03:51.711 Some of this damage is irreparable. 00:03:51.711 --> 00:03:53.845 • intense solar radiation can cause 00:03:53.845 --> 00:03:57.657 short and long-term damage to the eyes and skin. 00:03:57.657 --> 00:04:01.142 • short-term damage includes sunburn 00:04:01.142 --> 00:04:04.485 whilst the main long-term damage is skin cancer. 00:04:04.485 --> 00:04:06.376 • if the UV index is higher than 3, 00:04:06.376 --> 00:04:08.595 people should take simple precautions 00:04:08.595 --> 00:04:10.470 to protect against UV radiation 00:04:10.470 --> 00:04:13.015 or reduce the time spent outdoors.