Montreal opts for cooler LED lights after pushback over health risks

The City of Montreal is opting to replace 132,000 streetlights with 3000K LED lights, which give off a warmer huethan the ones it originally planned to install, in response to concerns about health hazards and light pollution.

After the city first announced its plans to replace the existinghigh-pressure sodium lightswith more energy-efficient LED lighting, some people expressed fearsthe 4000Klights it intended to usewould be too disruptive.

The 4000K lights emit a blue-rich light, closer to simulating daylight than the3000K LED lights do.

In guidelines adopted by the American Medical Association (AMA) in June 2016, the AMA cautioned against the use of LED lights which "emit a large amount of blue light that appears white to the naked eye and create worse nighttime glare than conventional lighting."

"Discomfort and disability from intense, blue-rich LED lighting can decrease visual acuity and safety, resulting in concerns and creating a road hazard," the AMA said.

Beyond driving hazards, it noted that blue-rich LED night-time lighting suppresses melatonin and "is associated with reduced sleep times, dissatisfaction with sleep quality, excessive sleepiness, impaired daytime functioning and obesity."

$100Mconversion

"After taking note of all the information, notably on the issues of security, light, atmosphere and public health, we chose to move forward with a less intense luminosity," Montreal Mayor Denis Coderre said in a statement.

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Coderre said the city is trying to strike a balance between health concerns and the need to make sure public areas are adequately lit, for safety.

"We want to make sure that in crossroads, in parks, that people will have the capacity to feel secure," he said.

It will take five years and cost $100 million for the city to replace all the light bulbs.

Of that money, $28 million will be spent on a smart lighting system that the city says will allow it to respond more efficiently to broken or malfunctioning lights, as well as monitor energy consumption.

The city expects to save 35 per cent on energy costs and 55 per cent on maintenance, once the streetlight conversion is completed.

Cities respond to medical findings

Adverse effects of LED lights have been identified in recent yearsas several U.S. and Canadian cities have moved to replace older streetlightswith more energy efficient ones.

The culprit, according to the AMA, is the amountof blue light emitted byLED lights with a higher Kelvin (K) value.

Lights in the2700Kto2800Krange are considered "warmer" lights, in the colour temperature range ofcommon incandescent light bulbs. Lights that simulate bright daylight are in the5000Kto6500Krange.

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Cities have responded in different ways to complaints about the adverse effects of the higher K-valuelights.

New York City switched to lower K-value LED lights after a growing number of complaints.

In Sherbrooke, the city's proximity to theMont Mgantic astronomical observatoryled to concerns about light pollution, and itoptedfor much dimmer 1800K LED lights.

Toronto is sticking to4000Klights over main arteries, and Seattle, Washington has reserved its right to use extremely bright4100K lights.