# UV content of sunlight at Dead Sea

**URL:** <https://boards.straightdope.com/t/uv-content-of-sunlight-at-dead-sea/223866>\
**Category:** Factual Questions\
**Created:** [January 10, 2004, 8:59pm UTC](https://boards.straightdope.com/t/uv-content-of-sunlight-at-dead-sea/223866 "2004-01-10T20:59:23Z")\
**Posts on this page:** 2\
**Page:** 1

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**Author:** ![hammerbach](https://avatars.discourse-cdn.com/v4/letter/h/73ab20/32.png) [@hammerbach](https://boards.straightdope.com/u/hammerbach)\
**Post date:** [January 10, 2004, 8:59pm UTC](https://boards.straightdope.com/t/uv-content-of-sunlight-at-dead-sea/223866/1 "2004-01-10T20:59:23Z")

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One of my co-workers insists that all the harmful UV from sunlight is filtered out by the atmosphere by the time you get to the altitude of the Dead Sea (~1300 feet below sea level). She saw this in a documentary. It doesn’t seem likely to me. Does anyone out there know?

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**Author:** ![Q.E.D](https://avatars.discourse-cdn.com/v4/letter/q/51bf81/32.png) [@Q.E.D](https://boards.straightdope.com/u/Q.E.D)\
**Post date:** [January 10, 2004, 9:19pm UTC](https://boards.straightdope.com/t/uv-content-of-sunlight-at-dead-sea/223866/2 "2004-01-10T21:19:01Z")

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UV is primarily filtered out by the ozone layer, which lies at an altitude of between 9 and 64 km (estimates vary greatly). It filters out some 99% of the dangerous UV-B and UV-C rays from the sun. Any filtering by other regions of the atmosphere is negligible in comparison, so below this layer, altitude plays essentially zero role in UV level.