The American Medical Association (AMA) recently released a statement warning of potential health concerns regarding LED streetlights and how to avoid these drawbacks. The warning originated on June 14th at the AMA’s annual meeting held in Chicago. There are new guidelines to follow in order for communities to “minimize potential harmful human health and environmental effects.”
More and more cities are replacing older lighting fixtures for new LED lights because they are more energy and cost effective and require less maintenance. In order to enjoy these benefits without drawbacks, it’s important that proper design is implemented. Otherwise, lighting can lead to serious human health issues.
New Guidelines For LED Lighting
The AMA states that outdoor lighting at night presents the most potential for issue, especially in regards to street lighting. In order to follow in line with the latest guidelines lighting color temperature should not exceed 3000 Kelvin (K).
Color temperature (CT) is a measurement used to define the spectral content of light generated from a source. How much blue, yellow, red or green is present in the light source? The higher the CT rating the greater blue content is in the light, and as a result the brighter/whiter the light appears.
Recent renovations in New York and Seattle have resulted in white LED streetlights that have a CT measurement of 4000K or 5000K, which far supersedes the latest guidelines. Lighting with this high of a CT rating has a high level of short-wavelength blue light. As a result of these blindingly bright lights there have been a number of complaints. For one, the lights are extremely harsh and if you live on a street near these lights they are going to filter into your home long past when you’re trying to go to sleep.
In Davis, California residents were so infuriated over the brightness of new city streetlights that they demanded the city completely replace them for lower color temperature lighting.
What Problems Do LED Streetlights Potentially Cause?
Traditional incandescent bulbs have a CT rating of 2400K, which means they are more yellow with red wavelengths. Since they do not contain nearly as much blue they appear far less bright. As a result, they have a decreased impact on people. Let’s take it back to the natural days when humans burned wood and candles for light sources. These light sources have a CT rating of around 1800K, which is a gentle hue of yellow and red with little to no blue at all. It’s easy to see that the latest shift to LED lighting is creating a much brighter light source than the world is used to, and perhaps even naturally able to handle.
New LED street lights are often incredibly white, blindingly so. The AMA cites two main issues with these bright lights…
1.Discomfort and Glare: LED is incredibly concentrated and as a result can give off a bright blue hue that leads to glare. The eyes react to this via pupillary constriction. As opposed to the longer wavelengths given off by yellow/red-based lighting, blue-based light scatters more in the human eye and can actually cause damage to the retina. This causes people to have more difficulty seeing at night either walking or driving.
So while streetlights are supposed to help us navigate in the dark, if they are overly bright they could actually increase the risks for accidents and make it more difficult to get around at night. You can experiment with these effects by looking directly into lighting on a new appliance. You’ll find that the high-powered light literally pains the eye, making you want to squint and look away. This does nothing to help you see better, but instead has quite the opposite effect.
2. Impact on Human Circadian Rhythmicity: This is the second problem outlined by the AMA in their statement. Color temperature dictates how much of each wavelength is present, but is specifically designed for light projected by tungsten filament of an incandescent bulb. The current CT scale is not able to accurately measure color projected by LED or fluorescent lighting.
There is another light measurement system used known as Correlated Color Temperature (CCT). This system adjusts spectral content of a given light source in accordance with color sensitivity of human vision. Under this rating system we find that there are large discrepancies between blue light content found in two lighting sources with the same 3000K rating. In other words, the current guidelines that state CT should be below 3000K are not sufficient in guaranteeing blue light is properly reduced. In order to correctly assess lighting and follow in line with regulations the spectral irradiance of the LED, or the actual colors produced, should be taken into consideration.
Light Pollution & Human Health
Light pollution is a serious problem in our modern day world proven to have impacts on human health. White LED light is estimated to suppress melatonin at night as much as five times more than high-pressure sodium lamps (traditional street lighting used for years prior to LED) even if they radiate the same light output. Higher levels of melatonin suppression equates to more sleep disruptions. In order to get a healthy, quality good night’s sleep it needs to be dark. Yet, when the streets are incredibly bright it makes it rather difficult for the body to turn off and sleep soundly.
It’s not just humans that are negatively impacted by all of this light. Wildlife can’t go inside and pull down blackout shades. They are left trapped in the brightness and powerless to turn it off. Bright lights have been found to disrupt migratory patterns of birds as well some aquatic animals that nest on shore.
Three Things The AMA Is Recommending To Address The Issue
The AMA is by no means trying to get rid Light Emitting Diode (LED) lighting. After all, LED light sources conserve energy and reduce fossil fuel usage. The AMA is simply advocating for a reduction in blue-based LED lighting in order to revoke glare and other negative impacts on human health and the environment.
The AMA states the need for: “the use of 3000K or lower lighting for outdoor installations such as roadways. All LED lighting should be properly shielded to minimize glare and detrimental human and environmental effects, and consideration should be given to utilize the ability of LED lighting to be dimmed for off-peak time periods.”
Energy efficient lighting is important, but so too is protecting human and environmental health. Thankfully, with the right design LED technology can provide energy efficiency as well as health and safety.