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Citizens Restoring Congamond
June 13, 2017
Light Pollution
Just a little glare across the lake
from dock lights can distract from the
beauty of the nighttime tranquility
Direct and reflected rays diagram
Skyglow is caused by the downward scattering of upward light by air molecules and also
aerosols, mostly water droplets and dust. The longer the path length through the lowest part of
the atmosphere, the more the scattering. Light that goes straight up is mostly reflected, and has
shorter paths through the lower scattering layers. The low angle light is mostly directly radiated,
and it is this that causes most of the sky glow well away from the source.
Reflected
Radiated.
Air molecules
Aerosols
Sky Glow
Sky Glow Effects
Good Neighbor Dock Lighting –
Minimize Glare and Light Trespass
Solar Dock Light
Lowes
$35
Minimum
Dock Light
with no glare
Limit the Amount of Light -
Reduce Cost and Light Pollution
Excessive lighting
Requires More
Fixtures and Energy
Lower light levels will
reduce costs for
Fixtures, installation and
Energy – and minimize
Light pollution
Light Trespass
The use of unshielded light fixtures
which cause light and glare to
cross the property line.
Partial Fix for Reducing Light
Pollution: Use Shielded Fixtures
Shielded “Porch Lights”:
bulbs do not extend below shield
Adverse Environmental Effects
from Light at Night
Light Pollution and Wildlife
Wildlife concerns due to obtrusive light include:
Habitat Disturbance
Wildlife Behavior
Wildlife Survival
A Few Examples: • Artificial Light Contributes to an Estimated 100,000,000 Bird Deaths Annually in USA
• Artificial Light Contributes to Thousands of Sea Turtle Deaths Annually
Attraction/Repulsion
For frogs, a quick increase in illumination causes a reduction in visual capability from which the recovery time may be minutes to hours
After becoming adjusted
to a light, frogs may be
attracted to it as well
Light’s Effect on Communication
• Female glow-worms attract males up to
45 m away with bioluminescent flashes;
the presence of artificial lighting reduces
the visibility of these communications.
• The complex visual communication
system of fireflies could be impaired by
stray light
Light’s Effect on
Community Ecology
• Competition for times for foraging
• Increased Predatory Risk
• Ecosystem effects – long term changes
in the balance
How Light Affects…
REPTILES
Disorientation from artificial
lighting causes thousands of
hatchling deaths each year in
Florida and is a significant
marine turtle conservation
problem
Artificial lighting is extremely detrimental to many insect populations:
• disrupts normal flight activity
• long distance migrations
• attracts insects that don't normally move from their habitat.
• are effectively trapped by the light,
• they can be killed directly by lamp's heat
• they may circle the light until caught by predators, or
Distant sky glow may also disrupt their migrations.
Light traps are very likely changing the diversity of insects
If a particular species does not reproduce rapidly enough to make up
for the loss at the lights, it may disappear from the community.
For insects that are important as pollinators, or predators of nuisance
insects, their loss is detrimental to human communities as well.
INSECTS
• One third of all human food requires a pollinator
• Many plants and flowers are pollinated by nocturnal
insects or small animals, moths and bats
• Altering the lighting conditions at night can further
unravel our web of life which ultimately disrupts
our food sources
FLOWERS – POLLINATION
PLANTS
Leaves near the
Streetlight
remain on the
tree – even after
all other leaves
have fallen off
Parental Exposure to Dim
Light at Night Affects Immune
System of Offspring
Ohio State University study published March 31, 2017
finds hamster parents exposed to dim light levels prior
to mating can result in offspring with weakened
immune system.
http://www.nature.com/articles/srep45497
Long-term parental exposure to dim light at night (dLAN)
prior to breeding was sufficient to depress cell-mediated
immunity in offspring.
Parental dLAN exposure prior to conception is sufficient to
alter offspring immunological responses and embryonic
development.
This was the first study that connected dLAN exposure of
adults with a transgeneration impact on offspring
Additional Ohio State Research Findings
1. the secretion of several hormones that regulate the
day-night-rhythm or growth.
2. essential processes like reproduction, which are partly
influenced by light.
3. In commercial aquaculture continuous light is used to
enhance growth of fishes by inhibiting the sexual
maturation.
4. artificial light at night (light pollution) interferes with
several physiological processes in fish.
With Fish, Light can control
How Light in the water affects fish
Light can influence freshwater
food webs
Light can change predator-prey
relationships
Juvenile and other vulnerable
fish might retreat to overhangs
and reduce foraging efforts in
order to avoid predation
American Medical Association Recommended
CCT Limits for LED Streetlights – 3000K
June, 2016 as adopted by the AMA:
“That our AMA encourage the use of
3000K or lower lighting for outdoor
installations such as roadways. All
LED lighting should be properly shielded
to minimize glare and detrimental
human and environmental effects, and …
to utilize dimming for off-peak hours”
American Medical Association
Recommended CCT Limits for
LED Streetlights
• 3,000 K (Kelvin) maximum
• Currently offered by Eversource
• Advisory issued June, 2016
• Eversource offers standard 3000K
but will vary upon written request
Electric Lighting at Night and
Risk of Breast Cancer
by Susan Brink
October 16,
2000
by Janet Raloff
October 17,
1998 May, 2001, page 86:
“People should get a
dark night’s sleep”
February, 2003
“Blinded by the Light”
(Canadian Edition)
Nature, October 31,
2002, NEWS item
From the IARC, Lyon: Parkin, DM, et al. CA Cancer J Clin, 49:33-64, 1999
0 50 100
Japan, 1950s
Breast Cancer Incidence Per
100,000 women/year (age-adjusted)
{ U.S. &
W. Europe
Eastern Europe
Japan (Today)
Africa
China
Ways to Limit Light Pollution
- Use light sources with limited short
wavelength emission (AKA “Blue Light”
content)
• Use Motion Sensors – light only when
needed
• Use lowest amount of light sufficient for the
intended purpose
• Use Timers to avoid lighting all night long
Lighting Issues on Health and the Environment
International Dark Sky Association
www.darksky.org
• Leo Smith – contact at leo@smith.net
• Thank you!
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