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Let there be (Less) Light 3 Reducing Light Pollution


What's wrong with this picture?  There'll be a short test at the end of this post

There are many ways to reduce light pollution. One way is through regulation, just as we have laws about excessive noise or air pollution. Here are some of the things which other countries, regions or cities have done.

Better Laws 

In 2002, the Czech Republic became the first country to pass laws about shielding of streetlights and to insist on flat rather than round glass, to prevent light spreading out in all directions. Solvenia introduced strong upper limits on lighting in 2007, exempting only those needed for security and safety. However, factories, airports, railways and ports may not use lighting which shines above the horizontal. A nice touch is the mention of endangered species. If there are nests on a building for example, that area may not be illuminated. 

In Italy a number of jurisdictions have enacted their own laws, but those which Lombardy introduced in 2009 are likely to become the EU standard. They include having no light above the horizontal plane, having lights out or reduced after 11pm (12 am in summer), almost always illuminating buildings from the top only, banning spotlights used for advertising, and protecting areas around astronomical observatories for 50 km in the case of professional ones and 30 km for public ones.

In 2013, to limit light pollution and save energy, France passed its first lighting ordinances. They called for lights in office buildings to be turned off one hour after the last worker had left. Exterior lighting of buildings had to stop by 1 a.m. and window lighting in shops had to be turned off between 1 am and 7 am.

 As of January 2019, France has some of the strictest laws in the world to reduce light pollution. They have two parts. The first includes technical requirements about the design and operation of outdoor lights on public and private property. The second is about setting aside 11 areas for astronomical observations, something which we'll hear more about in the next post.

Broadly, the first section covers the following:

·       Colour Temperature -Limiting the use of blue light LEDs as already discussed. Only up to 3000 Kelvins may be used anywhere, with a limit of 2,700 for parks, nature reserves and urban lighting.

While Kelvins are all about the colour temperature of light, LUMENS  are what you are likely to see on a light fitting. This measures the brightness of its output. LUX readings on the other hand, indicate the amount of light being received in a particular area over a specific time. One LUX is a measurement of one Lumen in one square meter. It has about the same intensity as a moonlit night.

·         Intensity -A maximum of 3.5 LUX per square meter at any specific location, with a maximum of 25 LUX within the city and as low as 10 LUX in suburbs and rural areas.

·         Limits on upward transmission of light, to 1% of a given light source. Modern best practice demands zero upward transmission, according to Stuart.

·         Limiting glare by having angles of light at less than 14.5 degrees from the horizontal. (Again, best practice is even stricter and calls for below 30o from the horizontal). 

·         Curfews apply  to commercial property and shop fronts. Lights must be extinguished one hour after the last person has left the building or at 1 a.m. in the case of shopfronts

·         Use of motion – sensing switches is encouraged. The law also applies to monuments and heritage buildings. Even the Eiffel Tower is planning to shut its lights down at 10 pm. an hour earlier than before.   

·         Use of sky beams, lasers and other powerful lights is generally prohibited especially in natural areas and places where astronomical observation takes place.

 ·         The lighting of waterways at night is also generally prohibited, including lights which shine out to sea.

·         Light trespass into dwellings is prohibited, regardless of source

·         Local authorities may grant exemptions for special events

With light pollution increasing at the rate of 10% per year and the negative effects of light pollution becoming more widely known, expect many more jurisdictions to follow France's lead.

A bonus for France has been that its new lighting restrictions have helped it to reduce its electricity consumption by 12% compared to pre -pandemic levels, and enabled it to reduce its power prices slightly. Sports stadia, parking lots and open -air entertainment venues are also in its sights. 

If your community doesn’t have bylaws about outdoor lighting yet, you too can be a dark sky warrior by advocating for them. Find out more here.. You can also become a member of your local Dark Sky Organisation and advocate for more dark sky reserves. See more about these and other interesting things to do under Dark Skies in the next post.

Other ways to reduce Light Pollution

This following video from the Australasian Dark Sky Alliance is a bit long (10 mins), but explains many of the following points in more detail.

Better Lights

The latest light fittings can be adjusted for lower intensity and better angles. For Dark Sky approved or certified lighting in Australia, click here. In the USA, IDAS certified lighting carries a special seal. By the way, a subset of the French directive is that lights and their components must be made more recyclable and reusable. The European Union has banned sales of fluorescent lights to save energy and prevent mercury pollution.

Better Targeting of Light

Lighting experts estimate that about 30% of lighting in Australia is wasted.  Much of this could be avoided by only using light where necessary, by shielding lights appropriately and by targeting lighting carefully so that it doesn’t spill over rooflines. This Let's Talk Science article shows how outdoor lighting should be shielded to avoid scatter and light pollution.

Tasmania’s Parliament House is an excellent example of good lighting, especially for a historic building. Despite being lit from below, which is now considered undesirable, the lighting was soft and even and highlighted its architectural features and its honey -coloured sandstone, without being obtrusive or harsh. It also stopped exactly at the roofline without lighting the trees or sky above it. Much more dignified than bright spotlights.

Parliament House - a well lit historic building

 Using Less Light

The use of timers, dimmers and motion sensors will all help to reduce light pollution. New Zealand is apparently far ahead of Australia on this. A curfew has been proposed for electronic billboards and the like because their light intensity can be as much as 10 times brighter than normal lighting and they are difficult to shield. Most of all, ask yourself if additional lighting is really needed.

On the subject of commercial lighting, our guide pointed out that the new trend in Europe for upmarket shops is to have very subtle lighting, highlighting specific objects rather than brightly lit window displays. It rather reminds me of my  ex -father -in law who would speak very softly if he wanted to have your full attention. You’d lean in close and be all ears. 

Why shout when you can whisper? Too much light leads to a veritable arms race between vendors

As far as domestic lighting goes, the simplest thing is to turn lights off when not in use and to have curtains or blinds to stop light spilling out into the environment. There is an Australian standard AS 4282 for this but it is difficult to prove that violations have occurred and it is almost never policed. Make sure any security lights are properly shielded, come on only as needed and do not light up a larger area than necessary.

So now do you know the answer to the first question? 

The spotlight is too bright, creating glare and dark spots. It repels rather than attracts and would disrupt birds and other wildlife in the trees opposite. Since it doesn't seem to be shielded in any way it most likely throws light upwards as well and adds to overall city light pollution and its sky glow. It is also a waste of  energy and money.

What you can't see in this picture, is how dangerous this 5 -way intersection has become due to the excessive and diverse types of lighting. Cars move in all directions, the already bright road lighting and traffic lights are overshadowed by the spotlights, making dark zones around pedestrian crossings and trees, while the competition between so many different light sources including those issuing from cafes and bars, distracts drivers and pedestrians alike.

The next post will be about some of the great things you can do under Dark Skies.