Light pollution
Content
Introduction
What is
“light
pollution” ?
Where does
it occur and
why is it
important?
When did it
all start?
Is there a
solution?
Introduction
• Light pollution is a
growing environmental concern
caused by excessive and
misdirected artificial light.
It affects ecosystems, human
health, and our ability to
see the night sky.
• This presentation explores
what light pollution is, its
origins, where it occurs, and
how we can address it.
• 80% of people on Earth have
lost their view of the natural
night sky due to artificial
lighting.
What is
light
pollution?
Light pollution is when there is
too much or unwanted artificial
light in the environment,
especially at night.
This extra light makes it hard to
see the stars, wastes energy, and
can harm people, animals, and
plants.
• Light pollution is measured by using
bortle scale, a nine-level numeric scale
that measures the night sky's brightness.
• We use a device called “Sky Quality Meter”
to measure the brightness of the sky.
When did it start?
19th-20th
century
• Light pollution began to emerge as a noticeable problem in the
early 20th century, coinciding with the widespread of electric
lighting in cities. While artificial light sources such as oil
lamps and gas lighting have been used for centuries, it was the
invention and mass deployment of electric light-especially after
Thomas Edison’s incandescent bulb illuminated a New York street in
1879-that marked the beginning of the modern era of light
pollution.
• By the early 1900s, urban centers were increasingly lit by electric streetlights, and
astronomers started to observe the detrimental effects of artificial lighting on the night sky
• Awareness of light pollution’s environmental and astronomical impacts grew gradually.
Some concerns about artificial lighting’s effects on wildlife and the night sky were noted as
early as the late 19th century, but the issue did not gain widespread recognition until much
later
Where
The
most?
In
In the
Egypt?
world?
Urban areas like:
Alexandria and Cairo
Countries: Qatar,
Singapore, and the
USA.
Cities: Doha, Hong
Kong,….etc.
The
least?
Remote deserts,
oases, and remote
rural areas
Greenland, Chad,
Australia….etc
Where
The most?
The least?
In Egypt?
Urban areas
like:
Alexandria and
Cairo
Remote deserts,
oases, and
remote rural
areas
In the
world?
Countries: Qatar,
Singapore, and the
USA
Cities: Doha, Hong
Kong,….etc.
Greenland, Chad,
Australia….etc.
Why is it
important?
Wildlife :
• Many migratory animals, especially birds, use the moon
and stars for navigation.
• Sea turtle hatchlings, for example, can be drawn away
from the ocean by artificial lights, leading to high mortality
rates.health :
Human
• Sleep disorders, exposure to light at night leads
to difficulty falling and staying asleep, reduced sleep
quality, and increased use of sleep medications.
• Affecting your mood as it can make you feel more
stressed, anxious, or depressed.
Astronomy:
• Stars and galaxies fade, so
telescopes can’t detect them.
• Miss calculations because of the poor
sky quality.
How to
solve it?
1-Redesign the lamp
posts
2- Use warm lighting
color
3- Less light
intensity
“If
possible”
4- Use motion
and light
sensors
THE LOGIC TREE
Are you willing to
help?
Conclusion
• Light pollution is a bigunderestimated problem that the
world must face and put an end
to it.
• We should unite our forces to
keep our sky beautifully full of
stars for the sake of humanity
and the wildlife.
• In conclusion, reducing light
pollution not only restores our
view of the night sky but also
benefits wildlife, saves energy,
and improves human health. By
adopting responsible lighting
practices, we can protect our
environment and enjoy the stars
for generations to come.