light pollution it's defenitions, types, and how to eradicate them with a case study

1. KASHYAP.V.
MTE-468

2. :
•Light pollution, also known as photo pollution or luminous pollution is
excessive, misdirected, or obtrusive artificial light.
•Scientific Explanations
Alteration of natural light levels in the outdoor environment owing to
artificial light sources
Light pollution is the alteration of light levels in the outdoor environment
(from those present naturally) due to man-made sources of light. Indoor light
pollution is such alteration of light levels in the indoor environment due to
sources of light, which compromises human health
Light pollution is the introduction by humans, directly or indirectly, of
artificial light into the environment

3. :
Light pollution is a broad term that refers to multiple problem
now according to the problems they have been further classified
•Glare
•Skyglow
•Light Clutter
•Light Trespass

4. Glare:
GLARE
It is a visual sensation caused by
excessive and uncontrolled
brightness. It can be disabling or
simply uncomfortable
Blinding
glare Disability
glare
Discomfort
glare
• describes effects
such as that caused
by staring into the
sun
• It is completely
blinding and leaves
temporary or
permanent vision
deficiencies
•describes effects such as
being blinded by
oncoming car lights, &
reducing contrast,
•as well as reflections from
print and other dark areas
that render them bright,
with significant reduction in
sight capabilities
•does not typically
cause a dangerous
situation in itself,
though it is annoying
and irritating at best. It
can potentially cause
fatigue if experienced
over extended periods

5. Example of lighting that can result in disability and discomfort glare

6. Sky Glow
•Sky glow refers to the glow effect that can be seen over populated
areas.
• It is the combination of all light reflected from what it has illuminated
escaping up into the sky and from all of the badly directed light in that
area that also escapes into the sky being scattered (redirected) by the
atmosphere back toward the ground.
time exposure photo of New York City at night shows skyglow , one form of light pollution

7. Light Clutter
•Light clutter refers to excessive groupings of lights. Groupings of
lights may generate confusion, distract from obstacles (including those
that they may be intended to illuminate), and potentially cause
accidents.
•Clutter is particularly noticeable on roads where the street lights are
badly designed, or where brightly lit advertising surrounds the
roadways
•Clutter may also present a hazard in the aviation environment if
aviation safety lighting must compete for pilot attention with non-
relevant lighting. For instance, runway lighting may be confused
with an array of suburban commercial lighting and aircraft
collision avoidance lights may be confused with ground lights

8. The Las Vegas Strip displays excessive groupings of colorful lights. This is a classic
example of light clutter.

9. Light Trespass
•Light trespass occurs when unwanted light enters one's property, for
instance, by shining over a neighbor's fence.
• A common light trespass problem occurs when a strong light enters the
window of one's home from the outside, causing problems such as
sleep deprivation
widespread trespassing occurring outside a grocery store parking lot

10. Scotobiology & LP relating study and findings :
•Plants developments usually occurs by seasons and they detect
seasons by duration of darkness
•Thus categorized plants into short day plants and long day plants ,short
day plants require long nights and long day plants require short nights.
•Short-day plants normally bloom in the autumn when the days are
shorter. Long nights initiate the onset of flowering, and later, as nights
lengthen, the onset of dormancy, which enables plants to withstand the
vigours of winter.
• If short-day/long-night plants are illuminated even briefly during a long
night, they detect this as two short “nights”, under continuous night-time
light pollution plants respond as if there were no night. In either case
flowering and development are compromised.
Cont….

11. •The effects of light pollution are also considerable at the
community and ecosystem level. Disturbance of plant and animal
life-cycles within a community affects the survival of otherwise
unaffected members.
•Human health is more severely affected by light pollution than is
generally realized. As Human hormone regulation, physiology and
behaviour have evolved in a diurnal pattern of night and day

12. Need for Light and Dark -Human Body Aspect
•Humans evolved under both light and dark night cycle, modifying it
will lead to health risks ,dark night is equally important to light period
for proper human health and well being.
•Cyclic daylight and dark night exposure controls the fluctuations of
body’s production of various hormones and this is known as
Circadian rhythms with about a 24 hr period.
•According to these circadian rhythms the hormones can be classified
into two general categories, visible light producing hormones(460 –
500 nm) and dark light producing hormones (> 600nm).
•The below two tables shows the various hormones and the relative
body functions

13. Circadian Blue Light 460 – 500 nm, Morning 6 – 10 am
Neurotransmitters
Cortisol
Serotonin
Dopamine
stress response
impulse control, carbohydrate craving
pleasure, alertness, muscle coordination
Neurohormones
CRF
Gastrin Releasing Peptide
Neuropeptide Y
FSH
TSH
Stress
hunger
hunger
reproduction
metabolism

14. Circadian Dark Response – above 600 nm No circadian blue after 10
pm
Neurotransmitters
Melatonin
Vasoactive Intestinal Peptide
Growth Hormone
Sleep
blood pressure
decreased body fat

15. Light pollution : Human Effects
Circadian Rhythm changes and problems associated with it:
•The production of melatonin is associated with circadian rhythms, and
changes in that will give a mix of health problems.
•The human immune response consists of two major pathways: Th1 (T
helper 1) [cell mediated immunity], which uses N-Killer (NK) cells and
cytotoxic T cells to destroy viruses and cancer, and Th2 (T helper 2)
[humoral or antibody-mediated immunity], which enlists B cells to produce
specific antibodies to help eradicate bacteria, parasites, and toxins

16. • Autoimmune diseases (asthma, rheumatoid arthritis) by imbalance
in Th 2 are more prevalent in the morning,
•while light at night prevents the nocturnal melatonin production, preventing
the activation of the anti-cancer N-Killer (NK) cells and cytotoxic T cells
which in turn increase the risk of cancer (breast and prostate).
•Night time workers have an increased risks of getting cancer due to
disrupted production of melatonin.
•Contrast Sensitivity
•Color perception
•Our ability to see contrasts
ALAN (Artificial Light At Night) and sleep disorders
•Weight gain
•Stress
•Depression
•Diabetes
Glare On eyes and problems associated with it

17. Light Pollution –Wild life Effects
LP (Light pollution) Effects on mammals:
A decline in reproduction, leading to a shrinking
population
Difficulty foraging for food due to too much light
Exposure to predators that would otherwise be
unable to see them
Increased mortality caused by impairment of their
night vision.
Examples of these affected mammals are bats,
raccoons, coyotes, deer and moose

18. LP effects on Birds:
Many species of birds migrate or hunt at night .This
dependence on darkness makes them extremely vulnerable to
bright lights in areas that are naturally dark.
•Collisions with lighted building and towers causes death
of many birds. It has been estimated that almost 100
million birds dies per year due to this collisions.
(North America).
•Not wanting to fly back into the dark, they continue to fly in the
light’s beam until they are exhausted, fall or become prey
•The artificial lights can also cause migrating birds to wander off
course and never reach their natural destination.
•Marine birds have been known to collide with lighthouses, wind
turbines and drilling platforms at sea.

19. Light Pollution Effects on Amphibians
The haze from sky glow extend far beyond the borders of an urban city,
impacting the environment for miles, including wetlands, the natural habitat of
amphibians. It causes amphibians and other creatures of the marshes to
become confused and disoriented, causing,
•A decrease in reproduction ,resulting in lower populations
•Reduced foraging for food and lower body weight
•Confusion of natural instincts that protect against predators and
Light Pollution Effects on Reptiles
Reptiles are greatly affected by light pollution, Nocturnal reptiles become
disoriented by the artificial light invading their homes and experience a
change on natural behaviors. These behaviors might include:
•Appetite problems resulting in decreased weight
•Decrease in mating, resulting in diminished populations.
•Increased vulnerability to natural predators and unusual ones like cars and
humans.

20. The one of the worst affected reptile by light pollution is Sea turtles,
• Female sea turtles like to nest on remote and very dark beaches.
Coastal lights interfere with their ability to find a safe nesting area for their
eggs.
•Sea turtle hatchlings crawl instinctively toward the relative safety of
ocean because of it’s reflection of the moon and stars. For centuries, this
reflection was the brightest point of light on a beach.
•Artificial lights can confuse the hatchlings and cause them to crawl away
from the ocean and onto roads or into communities. If they do not find
their way back to the ocean , they could become fatally exhausted or
dehydrated

21. Light Pollution effects on Insects
Moths and other insects are attracted to artificial lights and may stay near
that light all night. This activity round the light
•Expends too much energy and interferes with mating and migration,
causing population reduction
•Makes them easy prey for bats and other nocturnal predators,
further reducing their numbers Impacts all species who rely on insects
for food or pollination

22. Light Pollution –Plant life effects
•Most night lighting (ALAN) does not have the intensity to affect photosynthesis,
but it might affect trees that are sensitive to day length. Artificial lighting,
especially red light , extends the day length and can change flowering patterns,
and most importantly, promote continued growth thereby preventing trees from
developing dormancy that allows them to survive the rigors of winter weather.

23. Measurement of Light Pollution And it’s Units
Light
Photometry
• the measurement of light, in terms
of its perceived brightness to the
human eye
• It is based on the sensitivity of our
eyes to different wave length of light
Radiometry
•Radiometry is a set of techniques
for measuring electromagnetic
radiation, including visible light
• characterize the distribution of the
radiation's power in space, as
opposed to photometric techniques.
•Luminance (photometric quantity)(how bright a spot is)
Luminance is a photometric measure of the luminous intensity per unit area
of light travelling in a given direction. It describes the amount of light that passes
through, is emitted or reflected from a particular area. The SI unit for luminance
is candela per square meter (cd/m2)
•Illuminance (Radiometric quantity)
Amount of light hitting some surface is a useful integral measure in case of light. it it is
measured directly by a luxmeter; the quantity is then illuminance, its unit is lux

24. Measuring Light pollution:
 relative light pollution = man-made part of any photometric or radiometric quantity
natural part of the same quantity
In most cases, it is preferable to express pollution this way: as a dimensionless
number rather than by photometric units.
Double Relatively
Ratio of two contrast = Contrast polluted
Contrast Clean
•which are determined for a polluted and an unpolluted situations, is the best measure
of pollution, as regards the visibility of faint lights.
Where,
Contrast = luminance of target – luminance of background
luminance of background

25. Control Of Light pollution
Lighting Scheme Changes
Creating Environmental Zones
Design Aspects
Full cut off lighting Fixtures
 usage of different types and colors of light
Usage of automated light sensors
Limit Growth in installed lighting

26. How Lp Occurs
Lighting Scheme Changes:
•Light Sources
•Luminaries
•Installation
Light Sources: Light Sources Emitting ultraviolet radiations should be
avoided.(According to European Commite’s SCENIHR CFLs may pose an
added health risk due to the ultraviolet and blue light emitted)
Light Sources Emitting blue light should be avoided in night works(White
LEDs with high color temperature emit proportionally more blue light, and
International Dark Sky Discourages the using white light sources with
correlated color temperature above 3,000K

27. Luminaries
The most sensitive/critical zones for minimizing sky glow are those between
90ο and 100ο as shown in Figure and referred to as the lower, upward light
output zone (UL)
Installation
Keep glare to a minimum by ensuring that the main beam angle of all lights
directed towards any potential observer is not more than 70ο. Higher mounting
heights allow lower main beam angles, which can assist in reducing glare

28. When lighting vertical structures such as advertising signs, direct light
downwards wherever possible. If there is no alternative to up-lighting, as with
much decorative lighting of buildings, then the use of shields, baffles and
louvres will help reduce spill light around and over the structure to a minimum.

29. Environmental zones
It is recommended to divide the various areas into different environmental zones
and provide specific lighting environment in each of them.
Environmental Zones
Zon
e
Surrounding Lighting Environment Examples
E0 Protected Dark UNESCO starlight Reserves, IDA Dark Sky
Parks
E1 Natural Intrinsically dark National Parks, Areas of outstanding
natural beauty etc
E2 Rural Low district brightness Village or relatively dark outer suburban
locations
E3 Suburban Medium district
brightness
Small town centers or suburban locations
E4 Urban High district brightness Town/city centers with high levels of night
time activity

30. Where an area to be lit lies on the boundary of two zones the obtrusive light
limitation values used should be those applicable to the most rigorous zone.
NB: Zone E0 must always be surrounded by an E1 Zone
Design Aspects
ULR = Upward Light Ratio of the Installation is the maximum permitted percentage
of luminaire flux that goes directly into the sky.
Ev = Vertical Illuminance in Lux - measured flat on the glazing at the
centre of the window.
I = Light Intensity in Candelas (cd)
L = Luminance in Candelas per Square Metre (cd/m2)

31. Full Cut Off Lighting Fixtures
By far the best choice for lighting (apart from switching lights off altogether) is
the ‘Full Cut-Off’ lighting fixtures which direct their light output down only.
Full Cut-Off Lighting
•A luminaire light distribution where
zero candela intensity occurs at or
above an angle of 90º above nadir
•This should be the preferred type of
light fitting. Full cut-off fittings provide
excellent performance in all
situations, from the illumination of
streets to sports arenas and outside
lights

32. Cut-Off Lighting
•A luminaire light distribution where the
candela per 1000 lamp lumens does
not numerically exceed 25 (2.5
percent) at or above an angle of 90º
above nadir and
•100 (10 percent) at or above a vertical
angle 80º above nadir. This applies to
all lateral angles around the luminaire
Semi Cut Off lighting A luminaire light distribution where the
candela per 1000 lamp lumens does
not numerically exceed 50 (5 percent)
at or above an angle of 90º above
nadir and 200 (20percent) at or above
a vertical angle 80º above nadir. This
applies to all lateral angles around the
luminaire. These types of fittings
should be prohibited in ecologically
sensitive areas

33. A luminaire light distribution where there is
no candela limitation in the zone above
maximum candela. These types of fittings
should not be permitted by planning law
Use of different types and colors of light
•Adjusting the type of lights used, so that the light waves emitted are less likely
to cause severe light pollution is important
•This can include replacing older high pressure mercury vapor lights with
high pressure sodium vapor lamps and combining them with “full cut-off
luminaries” to reduce energy waste and glow
•Different wavelengths of light have different attractiveness to animals. White
lights appear to be the worst offenders for bird attraction, with yellow
lights performing better in this aspect. Red and blue lights are the least
attractive. This may be important in the construction of tall buildings with lights
on top of them and in the lighting of cranes etc
No Cut off Lighting

34. Turning lights off using a timer, occupancy sensor or manually
•Outdoor lights can be activated by motion sensors rather than a switch. These
motion sensor lights not only save energy but also reduce levels of light
pollution.
•Many motion detectors can be set so that they are less sensitive to the
movement of small animals. Particularly in the case of security lighting, Passive
Infra Red detectors (PIR) should be used whenever possible
Limit Growth in Installed Lighting
•Limits to the increase of the new installed flux should be implemented.
• A 1% yearly increase could be allowed at first for each administrative area,
followed by a halt in the increase of total installed flux, and then by a decrease
•This does not mean that no new installation will be allowed, but simply that if
you want to install new lights you have to decrease the flux in the existing
overlighted areas.

35. Lighting regulations
Few countries in the world has separate regulations for the control of light
pollution, which include US, Czech Republic, Italy, Slovenia, England and
Scotland (according to International Dark Sky Association database)
UNITED STATES OF AMERICA
In US, each state has established their own separate standards for controlling
light pollution, (16 out of 50) states has implemented these.
Arizona:
•AZ House Bill Title 49
California:
•California Energy Commission (CEC) Title 24: Energy Efficiency Standards for
Residential and Nonresidential Building
•Outdoor Lighting Zones - 2005 Building Energy Efficiency Standards
•CEC 2005 Building Energy Efficiency Standards, Section 132-Outdoor Lighting
Controls and Equipment
•CEC 2008 Building Energy Efficiency Standards, Section 132-Outdoor Lighting
Controls and Equipment

36. INDIA:
In India a National Lighting Code (NLC) has been established, SP 72:2010 by
BIS it briefly covers the following aspects of light pollution related factors,
a) Guidance on illuminating engineering practices to be followed by various
types of occupancies.
b) Guidance on good engineering practices to be followed in the design,
selection, installation and maintenance of lighting systems for indoor and
outdoor areas
c) Matters related to the science of illumination such as physics of light,
electric light sources, luminaries and photometry
d) Coordination aspects to be considered while designing the lighting systems
such as day lighting
e) Aspects relating to energy management and energy conservation in
lighting installations including guidelines for design and good practices to be
adopted for effective and efficient use of light sources.

37. Case Study: Light Pollution in Hong-Kong
Hong Kong is one of the most densely populated cities around the world and
the worst affected by light pollution (By Peter Shadbolt, CNN
March 21, 2013) In Hong Kong and many other major Asian cities, companies
compete for business by setting up large flashing signs and billboards
•In an attempt to draw a potential customer’s eyes, the owners make their
billboards flash rapidly and intensely. Since Hong Kong is so densely
populated, many businesses have sprung up in the area, leading to a greater
competitive atmosphere and creating a drive for bigger and more visible
advertisements
Methodology
The goals of project were two-fold: (1) to determine the extent to which
light pollution is perceived as a problem by the people living in Hong
Kong and (2) to recommend applicable lighting ordinances for reducing
light pollution in Hong Kong

38. Sources of Light Pollution in Hong Kong
•One of the objectives was to determine what the most problematic sources of
light pollution are for the people of Hong Kong. Using the information
collected from our survey, field observations, and interviews we were able
to estimate which light sources contributed the most to light pollution.
•the mean perceived contribution to light pollution for each of the sources on a
scale of 0 to 6, where 0 is ‘None Whatsoever’ and 6 is ‘Highly Excessive

39. Perceived Levels of Lighting
Perceived level of brightness Level of desired brightness
• A great number of respondents felt the current level of light outside their residences at
night is halfway between being bright as day and dark as night, i.e. levels 2 to 4
•The graph on the right of shows a large portion of our respondents desire lower levels
of lighting, i.e. levels 0 to 2.
•the average perceived level of brightness is 2.7, where the average level of
desired brightness is 1.5. This difference of 1.2 shows a major shift towards lower
levels of lighting

40. Perceived health effects of artificial lighting
Recommendations for proper controlling LP
•Infraction of light pollution ordinance results in monetary penalty
•All lights in certain zones must be off between certain hours of the night
•Light fixtures should be fully shielded and directed at its intended target
•A person may not direct any amount of light past his property lines without express
permission from the neighbor
•A special court may be set up which deals with light pollution infractions in a civil court
(similar to small claims court)
•Limitations on light fixtures
•Video billboards require government permits in order to be installed
•More researches for Light pollution in Hong Kong

41. CONCLUSION
•LP is a byproduct of industrial civilization, majorly from building
exterior and interior lighting, advertising, commercial properties, offices,
factories, streetlights, and illuminated sporting venues.
•As we have seen how drastically it affect our health (Humans),Plants
and animals it must be reduced .
•The most lucky factor behind light pollution is that it can be easily
reduced by adopting simple measures
•By controlling Light pollution we are also reducing energy wastage
•The need of laws for controlling light pollution is a must ,and in an
ever growing country like India ,by proper implementation of LP
controlling ordinances will help to solve this problem at an early stage
•Proper education of people for the need of darkness and various
factors relating to Light pollution must be reaching to common people.