The night sky: led Revolution

Part 2 in a series on Rick Scholes light pollution. See part 1.

You may have noticed that the lighting is often annoying nowadays. Ehring, you could say. Think of new vehicle headlights or our street lamps or even lights in our houses. If you are looking at them directly and it is difficult not to see, your ability to see something else is affected and you are even blinded for a moment. In the lighting world this is the definition of GlareAnd it is obviously not a good thing. Light should help our vision and do not affect it.

Shouting is an aspect of light pollution. In recent years it has become a topic due to the introduction of LED lights. LED lights now dominate all important lighting markets – home, street and automobiles and industry – because of their superior energy efficiency. The glare is a result of the color content or the spectrum of “white” LED lights. Your spectrum contains an unnatural amount of blue light. It is this blue that causes glare.

The view of LED street lanterns or the vehicle headlight or the LED light installed in front of your house is a safety problem and anger if it shines into another of another. These lights are not necessarily brighter than before (although they may be), but they have absolutely more blue content. Blue light sprinkles more than any other color. That's why our day sky is blue. At night our eyes use the stabbar receptors (Scotopic Vision). Rods are most sensitive to blue -green, so that a blue light is slightly saturated. That is glare.

In 2017, the city of Mississippi Mills testified all street lamps with the new LED technology. These lights are sick, but they are actually not Brighter than what you have replaced. I measured them. In our community we are lucky enough to have an increase in first lighting since 2003. It regulates the intensity of the street lamps. The old and the new lights all correspond to the statutes. However, the statutes do not take into account the glare factor of LED lights.

The color and glare differences between the new and old street lamps are very striking, as can be seen in the photo below in the King Street in Mississippi Mills. The LED is cool blue and white. The older light with high pressure sodium (HPS) is a warm orange white. (This special HPS light was not replaced because it is on school ownership.)

LED lights also carry for light pollution in the form of Skyglow. This is because all blue light that is slightly scattered by everything, of everything it has encountered – plasters, grass, structures, humidity, even air. Even if the LED light is not excited, a large part of its blue light goes into the sky. Cause the new LED street lanterns twice As much Skyglow as the previous lights.

A completely different problem in connection with LED lights is its spread. Their energy efficiency has prompted us to use more light as a society. We now shed light on many things that do not have to be lit because it is cheap to do this. The decorative lighting has shot up. Literature lights on houses, decorative lights in backyards and coastal lights on lakes sprout like weeds. But we don't have to light up much apart from our streets late at night. We never have to illuminate the sky. More lights than before and less motivation to turn it off leads to more light pollution. The efficiency gain, which was implemented by the move to LEDs, was compensated for by over -stress.

The glare, light pollution and overuse are unintentional consequences that have resulted from the LED revolution. The selection of LED lights with the slightest amount of blue content, the more thoughtful lighting and fixture design and the reduction or elimination of unnecessary artificial light include.

Now let's immerse yourself a little deeper into some important aspects of lighting technologies, why LEDs have taken over and what you have to look for if you are interested in solutions.

A short history of the LED

I have never imagined that light diodes (LEDs) would develop into a significant threat from light pollution when I worked for a company at the beginning of my career that produced LED didents (light emitting diodes). In the industry we have pronounced the LED as “Ell-Ee-Dee” and not “lead” as in the metal; They do not contain any leadership. They contain a semiconductor material that creates light very efficiently.

The LEDs were invented in 1962. In the early days, LEDs were good for the production of indicator lights and small displays, which mostly came in one color: red. Red LEDs were one of the technologies that made it possible for the first digital watches and calculators. Greens and Bernstein -Leds were also manufactured, but were less manufactured. None of them were bright enough to illuminate a room.

In 1993 a breakthrough led to the creation of blue LEDs. This was a player, since any other color can be made by combining blue, green and red. White light sources followed soon in 1996, although it took another 20 years of development to become affordable for the widespread use. The prices have dropped dramatically since the mid -2010s, which has led to market dominance.

LEDs have long life. Over time, they slowly reduce the brightness, but generally do not fail by burning out. They are small and compact. They are very energy -efficient because they work with low currents and tensions.

Efficient, long service life and adjustable colors – no wonder that you dominate the market.

Differences with older technologies

Fly bulbs have been the standard lighting technology for a hundred years. It was glass pears that contained a thin tungsten filament that shone hot with the energy supply wolf white. They are inefficient because they emit more energy than heat than light. The light bulbs usually burned out after 1000-2000 hours. The new LED light bulbs usually need about 15% as much electricity and take ten to fifty times as long.

High pressure sodium (HPS) gas discharge lamps were the prevailing technology used for street lamps in North America. They emitted an orange white light, as can be seen in the photo above. The new LED road lanterns usually need about 25 to 30% of the electricity, and their lifespan is expected to be 12 years or more (based on an 11-hour operating day). Both factors are considerably better than HPS.

The glass lens, which contained the sodium vapor in an HPS street lantern, towered down so that the lamp resembled the head of a Cobra. This contributed to the light pollution because the lens emitted the light on the side and upwards and down. An advantage that is advertised for LED streetlights are their “complete” housings that prevent light from going up directly. But as mentioned above, reflects or struts the blue component of these lights slightly in all directions from what you encounter, which negates the advantage of “complete cut-off”.

Color temperature and spectrum

The color temperature is the parameter used to define the color of a light source. Involved lamps were previously available in two general colors: “Hellweiß” (referred to by some manufacturers as “daylight”) and “soft white” (also “warm white”). The former were usually used in kitchens, bathrooms and workshops in which good details and color perspective were required. These had a color temperature of 4000 K – 5000K. The latter were preferred in residential areas and bedrooms because they were an eye on the scissors and more easily. They had a color temperature of 2000 K – 3000K. The color temperature is now marked with light products, but it was not always. Higher color temperature means blue, lower middle gesture. (Just like a hotter flame is blue and a cooler is yellow.)

How does a white LED produce your light? Surprisingly that may sound, there is actually No white LED! For commercial reasons, most “white” LED lights are produced by coating a blue LED with a phosphorm material. Some go through the phosphorus, while some are converted into yellow, green and red. Although the net result is white, LED lights inevitably contain a lot of blue.

To see how much blue we have to deal with the light of the light that shows the relative amounts of color. LED and incandescent lamps are compared in the following figure.

The LED light has a characteristic blue peak (arrow) that is never available in incandescent lamps or HPS lights. The higher the color temperature, the larger the peak. It is even more important that an LED light always has far more blue content than an incandescent lamp or a HPS light Even if the color temperature is the same. The replacement of 3000 KP lights with 3000K LED lights on our streets has caused more slight pollution.

Solutions

LED lights are here to stay. Light pollution and glare can be reduced by selecting lower color temperature -LEDs: 3000K are okay, 2700K are better. The relatively latest appearance of 2700,000 LED lights was partly driven by the demand from consumers for warmer lights. That's good news. The technology continues to develop. LED lights around 2000,000 are now available, in appearance quite orange, but contains almost no blue.

Office building lights, storage light, veranda and garage lighting, and the variety of decorative lights is often illuminated, since it is only considered a pennia for the company. People just don't think much about it. In most cases, they could be dimmed or switched off most of the night. Food rarely becomes cheaper, still the electricity rates. But we have the opportunity to switch off light when we go to bed and save some money that can be provided for more important things … like food. Imagine a loyalty point card: it adds up.

We need a counter -revolution to reduce the amount of light that we use and to move to those with less blue. The reduction of light pollution will also benefit us and all of our planets.

Part 3 of this series “The Night Sky: The Birds and the Bees” will check some of the stronger and less known effects of light pollution on ecology.