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[DSLF] Digest Number 1430

There are 6 messages in this issue.

Topics in this digest:

      1. Re: Full cutoff post lanterns
           From: Steve Davis <w2sgd@juno...>
      2. Boulder lighting ordinance goes into effect Sept 1
           From: "David Penasa" <dpenasa@unm...>
      3. More on melatonin - UV light and MLT
           From: Stephen Pauley <spauley@cox-internet...>
      4. Good discussions
           From: Stephen Pauley <spauley@cox-internet...>
      5. Re: RE: For Greg
           From: glennlaser@aol...
      6. Re: Article from Journal of Circadian Rhythms
           From: glennlaser@aol...


Message: 1         
   Date: Thu, 19 Aug 2004 08:57:16 -0400
   From: Steve Davis <w2sgd@juno...>
Subject: Re: Full cutoff post lanterns

Philip Gladsone wrote:
>I've just moved house and, lining my new driveway, I find six post
>lanterns (on 5 ft posts) that seem to be designed to shine directly into
>your eyes...
>Should I be replacing the poles with low level landscape lighting?

LR wrote:
>Decide if the lighting is absolutely needed or just ornamental.  If it's
>not a necessity, consider removing it instead of replacing it.

Right on!!!  Save the energy for something MORE useful AND
reduce [all forms of] pollution.

As Cliff likes to say, "Cars have headlights" to see the driveway
and you probably have streetlights anyway -- or use a flashlight.

After some practice, navigating your new driveway will be "old hat",
and you will be able to do it in the dark.  8-)   -sd

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Message: 2         
   Date: Thu, 19 Aug 2004 08:30:05 -0600
   From: "David Penasa" <dpenasa@unm...>
Subject: Boulder lighting ordinance goes into effect Sept 1

article on the front page of the CU Alumni e-newsletter received yesterday:

Lights out in Boulder
An ordinance that goes into effect Sept. 1 means the neighborhoods of
Boulder will be a little dimmer at night.
The new illumination ordinance requires all single-family residents to make
sure their outdoor lights don't shine across their property lines.
"The new ordinance is meant to minimize 'light trespass' on neighboring
streets and properties," says city Senior Planner Gary Kretschmer.


Message: 3         
   Date: Thu, 19 Aug 2004 14:30:29 -0600
   From: Stephen Pauley <spauley@cox-internet...>
Subject: More on melatonin - UV light and MLT

Greg wrote:
<<....the question of UV effect upon melatonin production. Is the degree of 
melatonin inhibition simply an upward slope into the higher light 
frequencies, or is it specific to a narrowband (blue, but not UV)?>>

The action spectrum for melatonin production (its % sensitivity plotted 
against wavelength (not frequency) of light) is a bell shaped curve that 
peaks at 464 nm (Brainard 446 -477 nm -blue.)  A small degree of melatonin 
suppression still occurs at each edge of the curve, i.e. at 450 and 550 nm.
The Journal of Neuroscience, August 15, 2001, 21(16):6405-6412
         Action Spectrum for Melatonin Regulation in Humans: Evidence for a 
Novel Circadian Photoreceptor

George C. Brainard1, John P. Hanifin1, Jeffrey M. Greeson1, Brenda Byrne1, 
Gena Glickman1, Edward Gerner1, and Mark D. Rollag2
1       Department of Neurology, Thomas Jefferson University, Philadelphia, 
Pennsylvania 19107, and 2 Department of Anatomy, Physiology and Genetics, 
Uniformed         Services University of Health Sciences, Bethesda, 
Maryland 20814

Just so you know it is not just I harping on the need to light for human 
health, Brainard states:
"Modern industrialized societies use light extensively in homes, schools, 
work places, and public facilities to support visual performance, visual 
comfort, and aesthetic appreciation within the environment. Given that 
light is also a powerful regulator of the human circadian system, future 
lighting strategies will need to provide illumination for human visual 
responses, as well as homeostatic responses. (underline by SP) The action 
spectrum presented here suggests that there are separate photoreceptors for 
visual and circadian responses to light in humans. Hence, new approaches to 
architectural lighting may be needed to optimally stimulate both the visual 
and circadian systems." (underline by SP)

The presumed photopigment for blue light absorption is melanopsin located 
inside a small group (1%?) of retinal ganglion cells located beneath the 
rods and cones and which connect to the circadian clock and then to the 
pineal gland. The rods and cones (visual receptors) also have minor 
connections to the clock center, but they are not the primary retinal cells 
that trigger the circdadian - melatonin response.  In other words, you can 
be visually blind and still have a melatonin-circadian rhythm.
J Neurosci. 2000 Jan 15;20(2):600-5.
         A novel human opsin in the inner retina.
         Provencio I, Rodriguez IR, Jiang G, Hayes WP, Moreira EF, Rollag MD.

Regarding some UV - Melatonin Suppression Studies
UV-A light also seems to trigger melatonin suppression..
The literature indicates that near ultra violate UV-A light (320-400 nm) 
suppresses melatonin in animal models. Because of the damaging effects of 
UV light on the human eye, human UV eye experiments are rarely performed.

The animal experiments tell us that in vertebrates, the 
eye-melatonin-circadian system is very sensitive in the lower wavelengths 
and less sensitive above 600 nm.  That is why, like it or not, LPS at 589 
nm is proving to be the most biologically friendly outdoor lighting source 
to both humans and ecosystems.Everyone hates the yellow color of LPS, but 
we may soon have to consider putting up with LPS, especially in residential 
areas where light trespass often enters bedrooms, as a trade-off for 
healthier outdoor lighting.

One study showed that UV-A (320-400 nm) suppressed melatonin in rats and 
Biol Signals Recept. 1999 Jan-Apr;8(1-2):64-9.
         Effects of near-ultraviolet (UV-A) light on melatonin biosynthesis 
in vertebrate pineal gland.
         Zawilska JB, Rosiak J, Nowak JZ.
         Department of Biogenic Amines, Polish Academy of Sciences, Lodz, 
Poland. jerzyn@amina1....lodz.pl
Another study demonstrated the same in a mouse using low wavelength UV-A at 
320 & 340 nm.
Brain Res. 1987 Sep 15;420(2):397-402.
         Suppression of pineal melatonin in Peromyscus leucopus by 
different monochromatic wavelengths of visible and near-ultraviolet light 
(UV-A).     Benshoff HM, Brainard GC, Rollag MD, Lynch GR.
         Department of Neurology, Jefferson Medical College, Philadelphia, 
PA 19107.
In this Syrian hamster study, melatonin was suppressed by UV-A, but  more 
photons were needed when using 360 nm UV-A than for 500 nm visible 
blue-green light.
Endocrinology. 1987 Jul;121(1):266-70.
         The suppression of nocturnal pineal melatonin in the Syrian 
hamster: dose-response curves at 500 and 360 nm.
         Podolin PL, Rollag MD, Brainard GC.
Joan Roberts, whom we know here as a dark sky warrior, has also done work 
on the affects of UV light on the immune system.
         J Photochem Photobiol B. 1995 Jul;29(1):3-15.
         Visible light induced changes in the immune response through an 
eye-brain mechanism (photoneuroimmunology).
         Roberts JE.
         Fordham University, New York, NY 10023, USA.
 From her abstract:
"The results presented here, as well as other data, demonstrate that
UV-A light is a powerful signal affecting the pineal melatonin-generating
system both in mammals and avians, and that the involved mechanisms
may differ in the tested species."
A nice summary article:

Seeing the Light
 in a New Way
Russell G. Foster
Journal of Neuroendocrinology;
Volume 16 Issue 2 Page 179  - February 2004
Steve Pauley MD

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


Message: 4         
   Date: Thu, 19 Aug 2004 14:41:15 -0600
   From: Stephen Pauley <spauley@cox-internet...>
Subject: Good discussions

Yesterday's discussions on fluorescent vs incandescent were
very good.  Cliff - thanks for the ref. pages.

I like the debates centered on such issues, and
when we home-in on color temperature and wavelengths, we
are getting to the heart of good lighting for humans not pavements.

It's time to pay the same or more attention to the wavelengths
of the outdoor light sources we use as to the lighting that
designers provide for indoor lighting, which these days is generally
quite good.

I did not intend to paint all fluorescent as bad.  But given the
choice of cfl vs incandescent for an evening reading light or living
room light, I'll choose the incandescent and allow my melatonin
to begin its normal, nightly rise.  Unless, that is, you experts
out there can tell me that there exists a 10 w cfl reading light with
lower blue emissions than the ave 40 w incandescent
(need brand names and wattages please).

During the day, bright, full spectrum fluorescent with blue emissions
are fine since they entrain the circadian clock to daytime conditions
and suppress melatonin- Nature's circadian pathway.

If the industry finally acknowledges the melatonin - health-
environmental issues and begins to make available to the public far more 
lighting fixtures with full cutoff shielding and spectra shifted more 
toward the
yellow-orange, the public's health and ecosystems will be well served.

Based on what we now know re blue light and melatonin suppression, there
is no place now for glare blasting, unshielded MH, MV, or HPS
outdoor lights.  Yet every major city in the USA and the world are loaded with
such lights as lighting engineers, designing by computer programs that
do not factor in the capabilities of the human eye, try to flood every
inch of pavement with photons from HID lamps.

This has to change, and I hope the human health concerns (and
environmental concerns) will be driving forces to make it happen.

IMO, the IDA with its MLO has taken this cause in the wrong direction.
If you doubt industry's financial take on this and how the IDA has
aligned itself with the industry rather than strictly holding to its goals
of really addressing the control of light pollution, please see this website:

Yes, HPS and MH are efficient and save energy, and yes, we need
to light our streets.  But HID lights must be used in far lower
wattages and housed in full cutoff fixtures.

Since over 50% of LP is from street lighting, the debates, IMO,
should center on how we misuse HID lights in cities, and why
that misuse is a hazard to human health and human safety, not
just from melatonin suppression but via glare and reduced vision
in a growing population of aging eyes with cataracts and age related
macular degeneration.

The industry and its lighting engineers have got to lead the way here.
Why?  Because, as Willie Sutton the bank robber said, "that's where
the money is."  The sooner the better.  So far, the industry's silence
on these issues (with a few exceptions) is deafening.

Steve Pauley MD  

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


Message: 5         
   Date: Thu, 19 Aug 2004 21:23:45 EDT
   From: glennlaser@aol...
Subject: Re: RE: For Greg

Well, not exactly. Fluorescent spectra are not the same as incandescent.  
Incandescent is "continuous" and most fluorescent "spiky." But your'e right  
about the rest.
In a message dated 8/19/2004 07:28:22 AM Eastern Daylight Time,  
DarkSky-list@yahoogroups... writes:

2)  Lighting engineers are protesting that modern fluorescent lights produce  
spectrum similar to incandescent lights and should not be identified  as
producing proportionally more blue than incandescent  lights.

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


Message: 6         
   Date: Thu, 19 Aug 2004 21:14:35 EDT
   From: glennlaser@aol...
Subject: Re: Article from Journal of Circadian Rhythms

My apologies for not be clearer about what my objection to your comments,  
and to the paper was. I wasn't referring to melatonin suppression or the  
potential negative effects of light on health. I was referring to the paper's  and 
your implication that fluorescent sources are inherently bad, and  incandescent 
You said:
(my all caps emphasis on "fluorescent")
"Below is an abstract from a simple Japanese study showing  that FLUORESCENT 
light (blue emissions) exposure to adolescents in the  early evening hours 
the onset of pineal gland MLT production.   One more reason not to use
FLUORESCENT lights in the home at night nor for  reading lights."
All I was trying to say is that there is no evidence in the paper (or  
anywhere else?) that fluorescent sources are any more likely to cause melatonin  
suppression than any other light source types. My understanding (and you know  
better than me) that the effect is wavelength, duration, and time of day  
dependent and not related to the light source type. I objected to the  implication 
that fluorescent sources should not be used in the home, especially  since the 
color temp of fluorescent typically used in home is the same as  incandescent 
In a message dated 8/19/2004 07:28:22 AM Eastern Daylight Time,  
DarkSky-list@yahoogroups... writes:

Message:  1         
Date: Wed, 18 Aug 2004  11:19:35 -0600
From: Stephen Pauley  <spauley@cox-internet...>
Subject: Article from Journal of Circadian  Rhythms

Glen wrote
<<Please, let's stop making unfounded  conclusions, especially based on 
a  paper
with a scarcity of  technical information about the procedure, and a   clear
It is true  that this "one paper doesn't make a summer".

However, my comments to  Greg were not based on this one paper alone
but rather on the hundreds I've  reviewed dealing with light at night, 
suppression, and the  potential negative effects on human health.

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


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