As we covered in a recent news article, the American Medical Association (AMA) recently issued some unsolicited guidance on the deployment of LED street lights and the potential impact on human health. We questioned the AMA's authority and knowledge on the matter at the time, and in fact have a column that further calls the recommendation into question coming in our July/August issue which will deploy digitally next week. Meanwhile, others including the National Electrical Manufacturers Association, and now the US Department of Energy's (DOE's) Municipal Solid-State Street Lighting Consortium (MSSLC) have voiced opinions on the AMA recommendation.
The AMA called for a limit of 3000K-CCT or warmer for outdoor lighting. Moreover, the recommendations also include other elements such as limiting beam spread to reduce glare.
The MSSLC sent out one of its "Light Post" emails that explains misconceptions that have appeared in the popular press relative to the AMA document, and that also points out flaws in the AMA thinking. Among the items in that newsletter is a table that accurately characterizes the blue energy in a variety of LED and legacy sources.
The MSSLC document also links to a response posted by consultancy LAM Partners and what that company points out as serious misinterpretations of the AMA document made by the popular press and even the International Dark Sky Association. For example, the IDA took a general statement on the magnitude at which blue-rich light might impact circadian cycles and applied it as an absolute fact whereas the AMA clearly said that practical measurements taken at street level are needed.
The LAM Partners document also repeats a common refrain from my prior articles. Cooler light may allow humans to see better and therefore allow lower light levels to be specified. And what we and the IDA should care about is reducing overall light levels while maintaining safety.
LAM Partners also scolds the AMA for a lack of fact checking. The AMA position paper inaccurately describes a Cambridge, MA LED street light project and misses the fact that the specifiers planned an adaptive-lighting design from the start as opposed to having dimmed lights based on public outcry.
NEMA, meanwhile, issued a press release responding to the AMA document. The association said the AMA recommendations align with some of the common tenets supported by NEMA members with regard to street lighting including light spill controls and minimizing light levels while maintaining a safe environment. But NEMA also noted that the AMA recommendation on spectral content is inappropriate and may compromise the ability of outdoor lighting installations to meet "critical design criteria."
Indeed, I think the AMA should either invest in the research to provide the organization a basis for issuing an opinion. Or the AMA should leave the subject of outdoor lighting to folks like the IES (Illuminating Engineering Society) members who are dedicated to and work tirelessly on the task.
