Just mentioned this proposal to Bob Mizon, coordinator of the BAA's Commission for Dark Skies, and got a rather pained response - I don't think he's too keen ion these! Obviously the damage something like this does depends somewhat on its location and how well installed it is but he agreed that such a display near somewhere like Wimbledon Common/Putney Heath where there is wildlife is likely to have a detrimental affect on the animals if they're nocturnal. He knows of one instance where bright LED security lights frightened the bats nearby and stopped them coming out of their roost for food so they starved to death (sorry, we were just chatting over a coffee so I didn't find out where that was). Although it's unlikely the bats on the common would be affected as dramatically as that it does demonstrate the undesirable affects bright LEDs can have in animals - and I'll included humans in that! The advertising signs are likely to be more damaging than new LED street lights which, if installed correctly, should face downwards to avoid light pollution. The advertising displays are likely to be vertical and high up to make them visible so they may well project light pollution over the horizon, and I'm told the harsh blue light from LEDs can be more intrusive than the warm glow yellow/red from sodium or incandescent lights. Another issue is that if the LEDs are too bright certain frequencies are reflected by the chemicals in plant foliage, so more light can be scattered increasing the pollution. Additionally, although as good drivers we may not read and be distracted by the advertising messages, the bright light may affect night vision, particularly in older drivers who may have the start of eye issues such as cataracts and whose pupil diameter will decreases with age making all, but especially night, vision worse. On the point of phones at night, we do not usually sleep with the bright screen on all night, it's normally in screen saver mode, so that's not the same as a nearby bright advertising screen on all night. Further, I attended a talk at IC recently on sleep by Russell Foster (Professor of Circadian Neuroscience and the Head of Department of Ophthalmology and the Sleep and Circadian Neuroscience Institute at Oxford University) and he wasn't altogether convinced of the results from the research into the use of mobile phones just before sleeping.
Michael Ixer ● 2777d