The Solutions

As light pollution impacts are many and affect various aspects, solutions to reduce this nuisance are just as varied. The idea of reducing light pollution is often interpreted as a need to stop lighting our environment at night, which is far from reality:  Reducing light pollution simply means to better light our environment.

 

Large scale dark sky protection will be achieved by concerted efforts in an area, like it was done in dark sky reserves and parks around the world. In this case, awareness-raising of officials and communities, implementation of regulation relevant to lighting and proper luminaire installation are desirable for the purpose of preserving the darkness of the night.

 

However, everyone can easily help this cause, first by being aware of the negative effects of light pollution and also by adopting sound lighting practices at home, whether in rural or urban areas.

Reduce intensity

Choose luminaires that produce low-keyed and constant lighting, with not too excessive light intensity. This will let the eye better adapt to ambient brightness while ensuring necessary visibility and site security.

Adjust orientation

Choose luminaires whose luminous flux is oriented towards the area to be lighted. Don’t forget that light emitted towards the sky does not help to see better and that light emitted towards the horizon contributes to glare.

Control time

Time and length of use of light fixtures must also be considered. Install a timer, a motion detector, or simply always turn off the lights before going to bed... the idea is to use only the lighting you need.

Limit blue light

Give preference to amber light sources over white ones, which are more harmful to sky glow and health, due to their large proportion of blue light.

All these solutions have been put in place with the creation of Mont-Mégantic International Dark Sky Reserve. For example, Cobrahead type street luminaires, with protruding diffusing lens were replaced with Helios type fixtures with flat lens, allowing for elimination of light spills towards the sky or the horizon. 

 

Moreover, intensities initially used were often way above real needs. Lighting power was generally reduced by half, producing less glaring and more constant light, favouring security while realizing important savings.

Cobra_vs_Helios_UdeS

Cobra_vs_Helios_LaPatrie

In all cases, high pressure sodium lamps (HPS) were used as opposed to halogen metal vapour and mercury lamps for a better luminous efficacy and a lower proportion of blue light. Blue light is the one that diffuses the most in atmosphere and compromises the most star gazing. Therefore, all sources of white lights are to be avoided in order to reduce the impacts of light pollution. In the MMIDSR territory, many farm mercury security lights and industry halogen metal vapour lamps were replaced by sodium lamps.

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FontaineSechoir1_APRES

The impact on a village like La Patrie was astounding! Seen from a distance, the amount of visible light and the impact on the dark starry sky has enormously diminished, but in the village itself, streets are better lighted by more secure lighting, less glaring, and less intrusive for villagers. Moreover, the use of a timer on church fixtures allows it to keep adequate heritage lighting early in the night, but to turn off the lights when there is no further need.

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With these solutions, today the whole region benefits from significant energy savings, warmly lighted nights and a sky with thousands of stars.