On 03/12/2016 12:44, Andrew Gabriel wrote:
In article ,
Scott writes:
As I mentioned elsewhere, I am experimenting with LED lighting.

I was having a curry with a former colleague last night, who mentioned
his father hates LED lighting for the following reasons:

1. The spectrum is too narrow thus depriving the body of the right
kind of light.
2. HIgh frequency flicker, higher than fluorescents possibly
triggering migraine.
3. Because of the frequency (colour temperature?) the light does not
travel as far so streetlamps need to be placed closer together but.
Councils are not doing this for cost reasons, leaving blackspots in
illumination.

Is there any merit in these arguments?

No.

Lighting industry did lots of experiments with CFLs to try and
understand what people didn't like about them. However, it was
quickly shown that these people didn't like lights they thought
were CFLs and did like light they thought were filaments.
Since what they *thought* didn't match reality, it could only
be put down to physicological bias, not genuine physiological
issues.

Couple of findings from peer reviewed sources:

"LED appears to support positive mood, extended wakefulness, and speeded
performance on both visual perceptual and cognitive tasks" in a work
context.

http://preview.tinyurl.com/gpymsdu (International Journal of Industrial
Ergonomics, 2012)

More general associations between LED light and well-being would need
somebody quite specialist, I'd think. Found this very odd sentence:

"Although highlighted in the scientific literature, concerns about the
potential impacts of increases in LED lights on cancer or other chronic
health outcomes were not raised by residents or key informants in any
settings in the fieldwork, public or private" (Reduced street lighting
at night and health, Health and Place 2015).

Overall, though, I think the evidence of a link between well-being and
LED lighting is weak. Trafford did a study using plain English which was
largely inconclusive: Trafford LED Street Lighting Programme Health
Impact Assessment (2013) - I've only skim read it though.

As for those physical/physiological relationships listed by the OP,
don't know - that literature is far too specialist for me.

I'd say anecdotally that I find the street lighting superficially bright
- it seems at first glance as though more is illuminated, but I can't
distinguish as much. Potholes for example - a big problem cycling at night.

At home (just about all LED now), I don't notice much difference between
tungsten and LED, once the problems of LED directionality and overly
bright source are removed. Decent bulbs and/or shades largely solve
these issues for me.

Never got on with CFL - glad to see(!) the back of them.

--
Cheers, Rob