The lights in Hounslow are made by the Dutch company Phillips, they were originally manufactured by a Spanish company called WRTL who were acquired a few years back, the actual LED lights in them are from a company called Cree who I believe are Chinese. They achieve their intense white light by putting a lot of blue spectrum light into the mix. There are several problems with what is happening in Hounslow. No real design process took place - the contractors Hounslow Highways used the old lamppost holes, popped new poles in place and another team slapped the new luminaires on. As the lights are highly directional, they used extra long poles to get the coverage. The net result was this highly directional light shining right into people's bedrooms (mine included) and front rooms, making many of them unusable without the equivalent of WW2 blackouts. This lack of design is causing a lot of nuisance, distress and light pollution overall. The lights also contravene British Standards BS 5489-1-2003 and 2013 and the Institute of Lighting Professionals Guide to Obtrusive Light. There’s a growing amount of research that is questioning the use of LEDs for street lighting that builds on our understanding of what happens when circadian rhythms are interrupted by shiftwork and exposure to other blue rich light sources before bedtime such as iPads, TVs, strip lights etc. The way blue light suppresses the production of melatonin and this can be reproduced in carefully controlled lab conditions. This isn’t exposure to some sort of radiation, it’s simply blue light – our stone-age brains think blue light means daytime and receptors are triggered to suppress the melatonin and keep us awake. Great in daytime, not so much at night. What the more recent research has looked at is what impact street lighting might have on us, especially while we sleep. Most of us do not have 100% blackout curtains so we’re in contact with blue light at night while we kip. Our brains, think, hey presto, it’s daytime, let’s suppress melatonin and get up. This kanckers our sleep patterns. I should mention that melatonin not only regulates the circadian stuff, it also has an important role in cells and some studies have drawn connections with melatonin and cancer. The jury is still out on this, but bodies as such as the American Medical Association, The Council for the Protection or Rural England, a recent Royal Commission on light pollution and the EU are all advising caution in using blue rich LEDs for street lights. This is quite a good look at different light types and their potential impacts:Evaluating Potential Spectral Impacts of Various Artificial Lights on Melatonin Suppression, Photosynthesis, and Star Visibilityhttp://www.plosone.org/article/info%3Adoi%2F10.1371%2Fjournal.pone.0067798This study puts forward a way of measuring the impact of particular types of light and creates a Melatonin Suppression Index for that purpose.These notes it cites are some of the most relevant ones to the discussion here if you wish to look at this in more depth:Hansen J (2001) Light at night, shiftwork, and breast cancer risk. J Natl Cancer Inst 93(20): 1513–1515. doi: 10.1093/jnci/93.20.151316.Blask DE, Brainard GC, Dauchy RT, Hanifin JP, Davidson LK, et al. (2005) Melatonin-depleted blood from premenopausal women exposed to light at night stimulates growth of human breast cancer xenografts in nude rats. Cancer Res 65(23): 11174–11184. doi: 10.1158/0008-5472.can-05-194517.Stevens RG (2009) Light at night, circadian disruption and breast cancer: Assessment of existing evidence. Int J Epidemiol 38(4): 963–970. doi: 10.1093/ije/dyp17818.Stevens RG (2011) Testing the light at night (LAN) theory for breast cancer causation. Chronobiol Int 28(8): 653–656. doi: 10.3109/07420528.2011.60694519.Kloog I, Haim A, Stevens RG, Barchana M, Portnov BA (2008) Light at night co-distributes with incident breast but not lung cancer in the female population of Israel. Chronobiol Int 25(1): 65–81. doi: 10.1080/0742052080192157220.Kloog I, Stevens RG, Haim A, Portnoy BA (2010) Nighttime light level co-distributes with breast cancer incidence. Cancer Causes Control 21: 2059–2068. doi: 10.1007/s10552-010-9624-421.Kloog I, Haim A, Stevens RG, Portnov BA (2009) Global co-distribution of light at night (LAN) and cancers of prostate, colon, and lung in men. Chronobiol Int 26(1): 108–125. doi: 10.1080/0742052080269402022.Haim A, Yukler A, Harel O, Schwimmer H, Fares F (2010) Effects of chronobiology on prostate cancer cells growth in vivo. Sleep Science 3(1): 32–35.
Russell Pearson ● 4330d