Take the survey! Plan on checking out the streetlights during the LED study (through May 19th). Lex-Ham and Public Works will host a night stroll and supply hard copies of the survey along with treats on April 12th from 8-9pm. Meet at Hague and Dunlap!
4000 Kelvin LEDs were chosen to replace the streetlight bulbs throughout Saint Paul. Lex-Ham is one of the first residential areas where they were implemented, starting on Portland Avenue in April 2016. The Lex-Ham Council office heard from several dozen neighbors with opinions or questions about the change.
One type of bulb will be tested per block on the following streets between Lexington and Griggs:
The Lex-Ham neighborhood will be used to test bulbs in the older lamp post style lights. Two other neighborhoods will be sites for testing bulbs in the newer lamp post style lights.
Here is a summary of information on 4000K blue-rich light gathered by Lex-Ham residents: Light-Emitting Diode (“LED”)
- brighter that traditional lights
- available in a variety of color temperatures
- have a longer lifespan
- more energy efficient that earlier generation bulbs
There have been no complaints about switching to LED, just the brightness and color temperature aspects. The concerns regarding the 4000K blue-rich LED bulbs are listed below.
a. Exposure to blue-rich light at night can lead to decreased melatonin secretion in humans
- Melatonin, secreted by the pineal gland, helps balance: reproductive, thyroid, and adrenal hormones and regulates the body’s circadian rhythm of sleeping and waking
- Lower melatonin levels have been linked to increased risk of cancer
b. The AMA adopted a position on LED street lights at their annual meeting June 14, 2016, recommending that the lighting should have a color temperature of no greater than 3000 Kelvin (K). The ones installed in Lex-Ham are 4000K. Incandescent has a CT of 2400K (Color Temperature (CT) measures spectral content – a higher rating means greater blue content and whiter light appearance). Here is a summary of the AMA recommendations:
- Supports reduced energy consumption of LEDs
- Encourages minimizing and controlling blue-rich lighting by using the lowest emission of blue light possible
- Encourages the use of 3000K or lower lighting for outdoor installations such as roadways and proper shielding be installed to minimize glare and lighting be dimmed for off-peak time periods.
c. Discomfort & Glare – causes pupil constriction and can damage the retina
d. Circadian Rhythm is disrupted by blue light in humans and other lifeforms