[DSLF] Digest Number 1282

[DarkSky-list@yahoogroups...]

There are 2 messages in this issue.

Topics in this digest:

      1. MH vs HPS
           From: Steve Pauley <spauley@cox-internet...>
      2. RE: MH vs HPS
           From: "Bryant Buchanan" <bbuchan@utica...>


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Message: 1
   Date: Sat, 21 Feb 2004 09:49:04 -0700
   From: Steve Pauley <spauley@cox-internet...>
Subject: MH vs HPS

 >> "Bryant Buchanan" <bbuchan@utica...>
I would also mention that just because long-wavelength light doesn't appear
to affect melatonin expression, we don't yet know what other effects it
might have. In some species, monochromatic long- or mid-long wavelength
light has negative biological effects. I would be reluctant to jump on a LPS
bandwagon simply because of the melatonin effect.
Clearly, more research is needed. It would seem most prudent to eliminate
all night lighting that is not absolutely needed (impirically based) for
safety and to aggressively shield all that that is necessary. Changing
spectral properties seems of lower priority to me than reducing the quantity
of artificial night lighting that we and other organisms are exposed to.>>
--------------------------------
Bryant  I agree, and I did hear your fine talk at the Feb. '02 UCLA conf. -
Ecological Consequences of Artificial Night Lighting.

My notes show that your frog studies found that frogs are very
sensitive to all forms of light and can hunt very well and
make random nests in complete darkness.  They also seemed to prefer
blue light.   Your colleague, Sharon Wise, told us that salamanders
are affected by all colors causing disorientation while full spectrum
lighting did not.

In the other conf. talks we learned that all wavelengths
of light affect ecosystems, but my overall impression was that yellow
had fewer negatives than the shorter wavelengths.

I agree that reducing the overall quantity of light is goal #1.
But re human health, melatonin is suppressed least by longer wavelengths,
and the reality is that humans are going to trump ecosystems
every time (surely humans area also part of ecosystems, but sadly,
most don't think of humans as being part of the whole.)

Some wish to see LPS disappear entirely as a choice for
street lighting.  There, I disagree.  I think fco LPS needs to remain as
a good choice for residential street lighting.

I don't see that happening until the human health-melatonin
issues receive more attention by all.  At that point, the bandwagon
we ride will be about how indiscriminate HID night lighting potentially
harms human health. After that, LPS will rise as the best choice in
residential areas.  Until then, lets push for fco, low wattage (35-50w) HID's
and use house side shielding where needed, or.... eliminate all
lighting where not absolutely essential.

BTW, I've never achieved  35 & 50 w HID limits in our ordinances, but I keep
trying.  So far the best we've done here is fco 70w hps on residential streets.
Our biggest obstacles are still the engineers married to uniformity
and to computer plots that don't account for the ability of the human eye
to see well in low light.
Steve P



[Non-text portions of this message have been removed]



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Message: 2
   Date: Sat, 21 Feb 2004 14:25:41 -0500
   From: "Bryant Buchanan" <bbuchan@utica...>
Subject: RE: MH vs HPS

Hi Steve,
I think we agree on pretty much everything.  I certainly agree with the
melatonin effect, and feel strongly that we need to protect against it.
As regards the salamander research, the yellow light of LPS would
probably be the most damaging. I agree that if we are going to have such
lighting, it should be of a type that minimizes environmental impacts
including energy use, pollution, impacts on wildlife and humans).

The only thing that I'm skeptical about is the necessity of street
lighting and other forms of exterior lighting in the first place.
Forgive my ignorance of urban lighting research, but have any carefully
controlled studies been performed that demonstrate that such lighting
does enhance safety, well-being, and health more than the alternative of
removal (and considering the negative impacts...big picture)?  It seems
that most of our tradition of having street lighting and residential
security lighting may be due more to tradition than optimized and
balanced effect on all parties involved.

If anyone is aware of such research, I'd be delighted to learn about it.
Thanks
Bryant




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