Light Pollution is U.G.L.Y.

By

Phil Inderwiesen, Ph.D. (IES Member)

January 4, 2007

Presentation to The Coastal Prairie Texas Master Naturalist Chapter

of Ft. Bend and Waller counties

Outline

• What is light pollution? • It’s U.G.L.Y!• How to recognize poor (and good)

outdoor lighting when you see it.• Wildlife and plant reaction to L.P. –

the new scientific field of Scotobiology• Acitivities/Web Resources

Light Pollution

Definition: Light pollution is excess or obtrusive light created by humans.

Effects:• obscures stars and interferes with astronomical

observatories• disrupts ecosystems• wastes energy• can cause adverse health effects

Light Pollution

Definition: Light pollution is excess or obtrusive light created by humans.

Effects:• obscures stars and interferes with astronomical

observatories (astronomical light pollution)• disrupts ecosystems (ecological light pollution)• wastes energy• can cause adverse health effects

Light Pollution Effect on Night Sky

Scotobiology (Scoto=darkness, biology=life)

• A new scientific field which studies the impact of artificial light on nocturnal wildlife.– An emerging realization:

Animals need food, water, shelter and space, but they also need darkness.

Full Cut-off streetlights canreduce this wasted light by more than one-half!

Houston

Up Light From North America

Annual cost of direct up light from streetlights:

Over $2 Billion Dollars;Maybe as high as $5 billion

Darkness Map For The United States

What’s at stake?Your health! Sleep patternsare disrupted by light. Also light-induced melatonin suppression.J. of Neuroscience, Aug. 2001

40% of population livewhere their eyes neverhave to become dark adapted to see at night.

Progression of Unmitigated Light Pollution

Average yearly growth rates of light pollution is as large as 5%-10% measured both in US and Europe

National Park System Recognizes Dark Skies as an Important Natural Resource

National Park Service Night Sky Observation Sites

Sky Glow from light pollution can affect dark sites over 200 miles away!

Arches National Park with sky glow from nearby Moab,Utah and more distant Grand Junction, Colorado

Light Pollution in Fort Bend Co.

5 miles

LZ - 1

LZ - 2

LZ - 3

Highest LightPollution

Lowest LightPollution

Fort Bend Co.

Brazoria Co.Wharton Co.

99/59 Intersection

Fulshear

Milky Way washed out at zenith

and invisible at horizon

Dark lanes in Milky Way visible which become washed out near horizon

Milky Way shows much dark lane structure

and zodiacal light seen on best nights

Up Light Obscures Light From Astronomical ObjectsThe Up Light is Scattered by Atmospheric

Dust and Water Vapor

George Observatory - 5.7 Magnitude Area with Light Pollution - 2.5 Magnitude

1999 - Texas House Bill 916 passed to regulate outdoor lighting

at state-funded facilities and roads.

2001- Texas HB 164 permits the Commissioners Courts of Fort

Bend and Brazoria Counties to enact light ordinances.

2001 - Committee presents outdoor lighting issues to late County

Judge James Adolphus and receives his endorsement.

2003 - After several revisions the proposed lighting ordinance is

submitted to Fort Bend County Commissioners Court

for consideration and review by County Attorney’s office.

2004 - Commissioners Court request hearing for adopting the

outdoor lighting orders and orders are adopted as law.

(Regulations are on the county web site)

Timeline for Fort Bend CountyOutdoor Light Ordinance

Outline

• What is light pollution? • It’s U.G.L.Y!• How to recognize poor (and good)

outdoor lighting when you see it.• Wildlife and plant reaction to L.P. –

the new scientific field of Scotobiology• Acitivities/Web Resources

* UP LIGHT

* GLARE

* LIGHT TRESPASS

* YOUR AWARENESS (needed to fight L. P.)

Light Pollution is UGLY!

UP LIGHT COMES FROM TWO SOURCESGLY

1. Direct light emitted above the horizontal by a bulb.

2. Light reflected by the surface below the lamp back into the sky.

Car Dealership using too much light!

Cement reflects up to 25% of light and asphalt reflects up to

6% of light

MV 175 W Unshielded70 Watt

High-Pressure Sodium

175 Watt Mercury Vapor

MV 175 W Shielded

Billboards with upward pointing lights are a source that can even affect migrating birds, especially in poor weather

Sports Facilities Can Be Fully Shielded

Unshielded Sports Stadium Lighting Shielded Sports Stadium Lighting

Fully Shielded Tennis Facility

40 foot-candles under canopy!

10 foot-candles under canopy

Gas Stations - OSHA requires only 5 foot-candles to refine fuel!

UGlare – Reduces visibility, security and safetyLY

Glare Reduces Dark Adaptation Only the perception of safety is true

High Glare No Glare

UGlare – Reduces visibility, security and safetyLY

UGLIGHT TRESPASS DEVALUES PROPERTY, CAN AFFECT HEALTHY

LIGHT TRESPASSDevalues Property,Trashy Appearance

Fully Shielded Flood Lights Prevent Light TrespassIf for security, then use a motion sensor. If for ornamental, then use a timer.

POOR FLOOD

GOOD FLOOD

POOR FLOODS GOOD FLOODS

Outline

• What is light pollution? • It’s U.G.L.Y!• How to recognize poor (and good)

outdoor lighting when you see it.• Wildlife and plant reaction to L.P. –

the new scientific field of Scotobiology• Acitivities/Web Resources

Common Light Bulbs (Lamp) & Efficiencies

LPS - Low Pressure Sodium (Yellow)

MV - Mercury Vapor (White)

MH - Metal Halide (White)

HPS - High Pressure Sodium (Orange)

175 Watt Bulb ($70/yr)31,830 lumens

17,100 lumens

10,360 lumens

7,140 lumens

7,140 Lumen Bulb 50 Watts, $25/yr

85 Watts, $36/yr

116 Watts, $45/yr

175 Watts, $70/yr

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Lesson: Don’t over light, pay attention to the bulb’s light output (lumens)

Typical Incandescent Bulb Information (Watts & Lumens)

Lumen Information on Box

Good lighting (note: fully shielded)* Directs light down (No Light Above Horizontal)

* Does not produce glare.

* Reduces light trespass.

* Provides even illumination allows us to see the

objects being lit and not the light source.

Poor Lighting* Up Light wastes energy.

* Causes Glare, Light Trespass and harsh illumination.

* Glare reduces our eyes’ ability to see properly in the

dark. Results in eye strain/fatigue.

Extremely Poor Lighting* Lights everything but what we want!

* Produces extreme Up Light, Glare, and Light

Trespass!

All Outdoor Lighting Should Be Planned!

• Determine the purpose for the outdoor light.

• Fully shielded fixtures are the best way to achieve maximum efficiency and reduce uplighting.

• Set the light up to run efficiently by preventing Up Light, Glare and Light Trespass. Use the proper illumination level and bulb type (Don’t over light the area).

• Consider putting the light on a timer or use a motion sensor.

• In darker areas, use less light to preserve night vision.

The result will be less money spent operating the light,better safety and health, and happier neighbors.

UGLYOUR AWARENESS IS THE FIRST STEP TO FIGHTING LIGHT POLLUTION

Start by seeing if you can improve your own property

UGLYOUR AWARENESS IS THE FIRST STEP TO FIGHTING LIGHT POLLUTION

Outline

• What is light pollution? • It’s U.G.L.Y!• How to recognize poor (and good)

outdoor lighting when you see it.• Wildlife and plant reaction to L.P. –

the new scientific field of Scotobiology• Acitivities/Web Resources

Reaction of Plants and Animalsto Light Pollution

• LP disrupts ecology of plants and animals (including humans) that require a nightly quota of darkness.

• LP may interfere with mating activity among nocturnal species and discourage zooplankton from feeding on algae.

• LP can delay nightly feeding excursions of nocturnal animals resulting in food intake limitations, stunted growth and depressed reproduction and survival.

• Strong lights attract certain insects away from darker areas hunted by nocturnal insectivores.

• Migrating birds navigating by starlight can be lead astray by lights, crashing into lit towers/buildings or circling until they become exhausted and fall to the ground.

“Vision” of Nocturnal Animals

From www.urbanwildlands.org

• More light gathering capability due to larger eye, lens, pupil.• Larger and more sensitive detector (i.e. retina) composed mostly of rods instead of cones – B&W vision.• Three or more rods are connected by a neuron while each cone is connected by a neuron. Thus, the nocturnal animal’s chance of seeing prey at night is greater, but the object is fuzzy.

• Thick reflective membrane behind the retina, “tapetum lucidum,” reflects light that missed the rods back to the rods for a second chance at detection.

• Enhanced hearing, even as advanced as echolocation in bats.

Devil’s Sinkhole near Rocksprings, TX

Light Pollution and Plants

• Scientific studies are scarce on plants’ departure from the norm when exposed to artificial light.

– Lacking are studies on the effect of light levels.– The light environment provides one of the strongest abiotic signals to

plants, there are four photoreceptor families.– Some plants have up to nine different photoreceptors.

• Many antidotal observations:– Branches of sycamores near street lights keep their leaves into late fall

and winter (effect of street lights is highly localized and long-term consequences of response is unknown.)

– Plane trees (sycamore) exposed to HPS lighting exhibited rapid and late season growth, but then suffered severe winter dieback compared with trees screened from lighting.

– Soybean plants as far as 100 ft from prison security lighting are prevented from developing normally.

– Cocklebur which are highly sensitive to light conditions still flower on schedule even along busy highways where car lights illuminate them.

– Deciduous plants (shed leaves as days grow short in the fall) are thought to by most susceptible to artificial light.

Light Pollution may interfere with mating activity among nocturnal species

From Ecological Consequences of Artificial Night Lighting

• Female Tungara frogs are more likely to choose a mate and be more discriminating in choosing a mate under dark conditions.

• The behavior change under lighter conditions: the frogs may perceive the threat that visually-oriented predators can now see them:

– Resulting in a hasty selection of a mate.

• Fewer nesting locations are available in bright light conditions as female frogs search out locations shielded by brush.

Light Pollution can delay nightly feeding excursions of nocturnal animals (red-backed salamander)

• Study used white lights to brighten select locations of the salamander habitat to a level slightly less than natural twilight, but more than the full moon.

• During the first two hours of nightfall, more salamanders were found actively foraging for insects in the darker areas.

• The activity difference disappeared later in the night.

Implications of study:• Artificial lighting has the potential to shorten

foraging periods, thus limiting food intake.• This can lead to stunted growth and

depressed reproduction and survival.• Decades-old research shows that amphibians

calibrate their activity to the moon’s cycles with least activity associated when the moon is brightest near full moon.

• Since sky glow from light-polluted sites outshines the moon for nearly half of each month, it can extend the influence on reduced amphibian activity to longer than the full moon.

Study by Buchanan and Wise, Utica College in New York

Light Pollution affects both Bats and Insects

• Insects are drawn to streetlights providing a good and predictable food source for bats. HPS lamps attracts fewer insects than Mercury Vapor and other white lights.

• Bats will congregate around streetlights according to their size, speed, maneuverability.

• Moths will generally drop their defense mechanisms including evasive maneuvers, cessation of flight, and ultrasonic warnings while around a light (presumably thinking it is daytime and a bat source of ultrasound is unlikely).

• Not all bats (e.g. European lesser horseshoe bat) will utilize the food source around lights and stick with the more lean natural dark environment and can be displaced by bats that do exploit street lights.

• No study exists on how bat predation at streetlights affect the sizes of moth populations. From Ecological Consequences of Artificial Night Lighting

Migrating birds navigating by starlight can be lead astray by lights

• Migrating birds fly towards artificial lights at night and tend to circle the lights once encountered.

• Steady red lights on towers more attractive than white lights. Flashing lights less attractive.

• October 7, 1954 - 50,000 birds killed by flying into the ground following a beam from a guide light at Warner Robins A.F.B.

• On a rainy, foggy night in 1981, 10,000 birds collided with the floodlit smokestacks at Ontario’s Hydro Lennox Generating Station.

from Clarke (1912)

• Urban Bird Treaty (2000) between the City of Chicago and US Fish & Wildlife asks that office and tenant buildings turn lights off during the spring and fall migrations.

• Partial Solutions: – Fully shielded lights should be used to

mitigate skyglow and glare.– Fatal Light Awareness Program (FLAP) to

turn off building architectural lights at night during migration season and nights with poor visibility.

– Top down lighting of billboards.– Use flashing lights instead of flood lights on

smoke stacks.– Eliminate installation of unnecessary

lighting.

Outline

• What is light pollution? • It’s U.G.L.Y!• How to recognize poor (and good)

outdoor lighting when you see it.• Wildlife and plant reaction to L.P. –

the new scientific field of Scotobiology• Acitivities/Web Resources

Simple Ways to Enjoy Natural Darkness

• Try walking outside in a dark environment without using a flashlight.– No Moon: Find a comfortable spot and look around. Allow your eyes 20 minutes

to adjust to the darkness. Then try to see by starlight (you will be surprised) and listen to sounds (are the sounds louder?)

– Full Moon: Let your eyes fully adjust. Be safe. A full moon provides enough light to see and a hike under the full moon will be a memorable experience.

• If light is needed at night, use a small, red filtered flashlight to protect your night vision and the vision of any nocturnal animals you may come across.

• Many animals live their "days" at night. Look for nocturnal wildlife such as owls, coyotes, bats, deer, raccoons, opossums, armadillos, fireflies.

• Study the night sky. It has been an inspiration for myth, literature, art, scientific discovery, and religion. Revel in its beauty and wonder, and most of all – be inspired!

• Spend time looking through a telescope (stargazing) and learning about the cosmos with your local science center, astronomy club, or park ranger.

• The Brazos Bend State Park and George Observatory are good local resources.

Resource: National Park System

Web Resources• Fort Bend/Brazoria County Outdoor Lighting Ordinance Resource -

http://www.tovinder.net/lighting/light_ord.htm

• International Dark-Sky Association - http://www.darksky.org

• Citizens for Responsible Lighting - http://www.crlaction.org

• Outdoor Lighting Associates (Texas) - http://www.outdoorltg.com

• Outdoor Light Vendor with LP reduction as a goal

-http://store.starrynightlights.com

• National Park Service –http://www2.nature.nps.gov/air/lightscapes/