It was good to see the LightAware charity highlighting the particular problem of blue-rich LEDs in the discussion on the rise in light pollution (Letters, 7 November). I loved Jacqueline Yallop’s rich and vivid article (Everything from our sleep to our hormones relies on the dark. So why are we so intent on destroying it?, 31 October), but felt it missed this important point: it is not just the quantity of light that has changed in recent decades, but the quality of that light.
The rush to transition to LED lighting resulted in a botched job: councils throughout the UK installed light in our public buildings and spaces, and in our streets, that was far too intense and contained too much blue light. This is precisely the wavelength of light that most disrupts the circadian rhythm –not just sleep but almost every other physiological process – in humans and the rest of the natural world.
A study by Dark Sky International summarises the available science on light pollution. It questions whether the transition to LED street lighting provides any meaningful environmental benefit, and talks of “greenwash”. There’s no doubt about the harm caused to the overall health and wellbeing of people, with the lives of light-sensitive people being devastated, and by the disruption of natural ecosystems. It has also exacerbated light pollution due to the way blue light scatters and creates more “sky glow” – the smudgy veil of artificial light that obscures the stars.
Blue-rich LEDs have made our world uglier, changing the colour of our towns and cities from a soft orange glow to a harsh, gloomy glare. Light doesn’t just illuminate our surroundings, it creates the very world that we perceive and interacts with life in profound and subtle ways. We need to use it with great care and caution.
Author of Incandescent: We Need to Talk about Light