LED Streetlights Carry Hidden Risks, AMA Warns

According to new policy guidance issued this week by the American Medical Association (AMA), safe LED lighting options should be used in communities to prevent glare, retina damage, and other harmful effects to humans and the environment. 

The AMA held its annual meeting in Chicago last week, and one of the topics discussed was LED lighting and the potential health risks for communities. In a unanimous vote, the AMA adopted new guidance for communities on selecting LED lighting, focusing on dimmer and cooler lighting options.

The organization warns that recent community conversions to light emitting diodes (LED) may have “improper adverse consequences.”

Most people know LED lighting as energy efficient, offering cost reductions and energy savings as well as a lower reliance on fossil-based fuels. So far, about 10 % of existing U.S. street lighting has been converted to LED technology with efforts to accelerate the conversion.

However, the AMA warns LED lights emit large amounts of blue light, which appears white to the naked eye, but may can cause severe nighttime glare, more so than conventional lighting. This can create discomfort and disability, causing pupil constriction, decreasing visual acuity and safety, damaging the retina and causing more road hazards. the organization warns.

LED lights also operate at wavelengths that suppresses melatonin production during the night. Researchers estimate that white LED lamps have five times greater negative impact on circadian sleep rhythms than conventional street lamps.

Research indicates brighter residential nighttime lighting is associated with reduced sleep times, dissatisfaction with sleep quality, excessive sleepiness, impaired daytime functioning and obesity.

“Despite the energy efficiency benefits, some LED lights are harmful when used as street lighting,” said AMA Board Member. Dr Maya A. Babu. “The new AMA guidance encourages proper attention to optimal design and engineering features when converting to LED lighting that minimize detrimental health and environmental effects.”

The organization also said LED lighting affects more than humans by disrupting species that need dark environment. LED lights often disorient some bird, insect, turtle and fish species. As a result the national parks adopted optimal lighting designs and practices that minimize the effects of light pollution on the environment.

The AMA is recommending LED lights have a color temperature of no greater than 3000 Kelvin (K), which is a measure of the spectral content of light from a source and indicates how much blue, green, yellow and red it contains.

A higher CT rating means more blue content and a whiter light. White LED light has a CT of 4000K or 5000K, which is a high level of short-wavelength blue light. In comparison, incandescent bulbs have a color temperature of 2400K, which gives off less blue light, where as burning wood and candles has a CT of about 1800K, nearly no blue light.

Most major cities that have retrofitted to LED lighting, including Seattle and New York, have chosen color temperatures in the 4000K to 5000K range.

The AMA policy encourages communities to minimize and control blue-rich lighting by using the lowest emission of blue light possible to reduce glare and also recommends an intensity threshold for optimal LED lighting.

The organization also recommends all LED lighting be properly shielded to minimize glare and “detrimental human health and environmental effects.” Dimming for off-peak hours should also be considered where possible.

“The guidance adopted today by grassroots physicians who comprise the AMA’s policy-making body strengthens the AMA’s policy stand against light pollution and public awareness of the adverse health and environmental effects of pervasive nighttime lighting,” according to the AMA policy statement.