While the ozone layer in the upper atmosphere plays an important role in limiting harmful ultraviolet light reaching the Earth's surface, low-level ozone is a pollutant that is harmful, causing respiratory problems in animals as well as well-documented cases in humans.

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At ground level ozone is a dangerous pollutant, but at altitude it blocks the passage of harmful ultraviolet light.

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It was also a big week for lighting news as we learned that compact fluorescent light bulbs emit potentially harmful UV radiation -- another good reason to make the switch to LEDs.

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When it is ground into nanoparticles it can still block harmful ultraviolet radiation, but it allows visible light to pass straight though, which means modern sunscreens can appear completely transparent, while offering the same protection as the old white stuff.

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"The good news is that people who stay up late in front of the television and computer may be able to undo some of the harmful effects just by going back to a regular light-dark cycle and minimizing their exposure to artificial light at night, " Bedrosian says.

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'She likes to loosen light bulbs, to lock doors - but nothing harmful.

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The way agency search is practiced now is too slow for a marketing world that runs at the speed of light, and it is too expensive for companies (and agencies) that need to prevent harmful waste.

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Bob Mizon, an astronomer and campaigner against light pollution, thinks that Britons have lived with excessive illumination for so long that few notice its harmful effects.

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