Light Pollution

1
(No Transcript)
2
Light Pollution
3
(No Transcript)
4
Why is light directed upward?
5
Light directed upward is wasted.
6
Los Angeles from Mount Wilson Observatory 1908
7
Los Angeles from Mount Wilson Observatory 1988
8
Wouldnt it be more effective to put the lights
above and direct it down?
9
Too much light goes upward. needs better
shielding
10
better shielding very little goes up
11
Street Light Spectra
Low Pressure Sodium
High Pressure Sodium
Mercury Vapor
12
Street Light Spectra
Low Pressure Sodium
High Pressure Sodium
Mercury Vapor
13
Street Light Spectra
Low Pressure Sodium
High Pressure Sodium
Mercury Vapor
14
Low Pressure SodiumOrion
15
Filtered
16
Low Pressure Sodium

• best outdoor lighting for all safety concerns
• pierces fog
• expensive bulb
• energy efficient
• brighter than high pressure sodium

17
Why dont people like low pressure sodium?
18
Why dont you like low pressure sodium?

• dont like the color
• cant see color
• looks like the traffic signal
• exceptions?

19
high pressure sodium
20
Mercury Vapor
21
Low Pressure Sodium
22
Recessed Lighting
23
Light Trespass
24
Does more light mean less crime?
25
Crime
98
80
Adequately Illuminated
2
20
26
loss of night vision glare
27
Light Pollution

• Losing Battle
• Rational Argument Against
• Emotional Argument in Favor
• Population Growth

28
San Diego Southwestern College Texas High
School aircraft carriers NY subways