Lecture Fourteen - Light Pollution

Question 1

Give and describe the unit for measuring light intensity.

Answer 1

Lux

Measurement of how humans perceive light.

Question 2

What is the increase in lux from 1923-1999 in Britain?

Answer 2

0.8 - 13.1

Question 3

What used to be the major source of light, and has now mostly been faded out?

Answer 3

Mercury vapour light

Question 4

What are the cons of mercury vapour light?

Answer 4

• Expensive to make
• Not very energy efficient
• Wet bulbs break

Question 5

What were mercury vapour lights replaced by?

Answer 5

Low-pressure sodium lighting

Question 6

What were low-pressure sodium lights replaced by?

Answer 6

• High-pressure sodium lighting

- LEDs

Question 7

What can be said about the light emitted from low pressure sodium lighting?

Answer 7

It is almost monochromatic, emitting 600nm pure orange light.

Question 8

What is the difference between light emitted from low pressure and high pressure sodium lighting?

Answer 8

• Low pressure is almost monochromatic

- High pressure has a greater spectral range.

Question 9

Give the range of optimum light perception for mammals.

Answer 9

400-600nm

Question 10

What colour light do insects have visual sensitivity to?

Answer 10

Blue light

Question 11

What is the main colour of light found in mercury vapour lighting?

Answer 11

Blue light

Question 12

In what kind of lighting are colours most difficult to identify?

Answer 12

Mercury vapour lighting

Question 13

Why did we move away from low pressure sodium lighting?

Answer 13

It is difficult to identify facial expressions from a distance.

Question 14

What is the main colour of light found in LEDs?

Answer 14

Blue

Question 15

Why are dark patches between light installations avoided by light engineers?

Answer 15

Takes some time for drivers’ eyes to adjust to changing light levels.

Question 16

Why could dark patches be useful ecologically?

Answer 16

Act as a dark passageway for animals that don’t like light.

Question 17

What causes sky glow?

Answer 17

Reflective light hitting a hard surface, or escaping upwards from a light fitting.

Question 18

When is sky glow worse?

Answer 18

• Cloudy nights

- When ground is wet

Question 19

What is an ecological effect of sky glow?

Answer 19

Could affect navigation.

Question 20

What type of light design is most likely to produce sky glow?

Answer 20

Balled lights

Question 21

Give the proportions of light destinations for balled lights.

Answer 21

• 50% waste
• 10% glare
• 40% productive

Question 22

How could light pollution in the environment affect the migration of animals?

Answer 22

• Many use celestial cues when migrating
• Cannot see stars
• Could cause difficulties in migration

Question 23

What colour lighting do birds use to calibrate their magnetic compass?
What colour light disrupts the compass?

Answer 23

• use blue-green light

- red light disrupts this

Question 24

In what particular weather are birds attracted to lights?

Answer 24

Cloudy weather

Question 25

How can we change lighting on gas extraction rigs?

Answer 25

Place filters over the lights to filter out some wavelengths.

Question 26

What colour light for birds causes the a) Most encounters? b) Least encounters?

Answer 26

a) Most encounters with white light | b) Least encounters with blue lights.

Question 27

Why can't blue lights be put in oil rigs?

Answer 27

If you cut yourself, can't see the bleeding.

Question 28

What colour lights are attractive to fish?

Answer 28

Green

Question 29

Are Greater Horseshoe bats found more in dark or light areas?

Answer 29

Dark

Question 30

Describe the characteristics of light shy species of bat.

Answer 30

- Late emerging - Slow flyers - Moth specialists

Question 31

Describe the characteristics of light tolerant species.

Answer 31

- Early emerging - Fast flyers - Use early-emerging insects

Question 32

Give two species of light shy bats.

Answer 32

- Horseshoe | - Long-eared

Question 33

Give two species of light tolerant bats.

Answer 33

- Noctule | - Pipistrelle

Question 34

What group of bats have been found to have more activity around lights than away from them?

Answer 34

Leisleri bats

Question 35

What tones of light attract larger moths, noctuids?

Answer 35

Blue (LEDs)

Question 36

What percentage of a brown long-eared bat's diet is noctuid moths?

Answer 36

80%

Question 37

Why could it be an advantage for bats to feed on moths around streetlights?

Answer 37

- Moths can hear echolocation cries of bats - The drop-out response of moths is impaired by presence of light - Moths could be easier to catch

Question 38

What is the effect of Chironomid emergence in high or medium light?

Answer 38

Greater numbers of Chironomids emerging.

Question 39

What is the effect of mayfly emergence in high lighting?

Answer 39

Won't emerge at all in high lighting.

Question 40

What is the effect of Trichotopert levels in high lighting?

Answer 40

Majorly reduced.