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Light pollution modelling the UK Highways Agency new environmental policy, inc. astronomical impact of blue- rich LED luminaires.

The Highways Agency are replacing their policy of full cut off class G6 road lighting specification on motorways (originally based on the author’s work), and are adopting a categorised environmental impact based point system that can accommodate technical advances, such as LED lighting. The Skyglow component of this will be based on the modelling of skyglow versus cut-off angle, developed for determining the relative light pollution environmental impact of different streetlight designs, by the author. Further modelling has been done concerning the effect of LED lighting, which potentially, has highly directional properties. But increasingly used blue rich colour temperatures may increase skyglow by 5 fold, compared to traditional lighting. This is due to enhanced reflection of vegetation and greatly increased atmospheric molecular Rayleigh scattering; a potential astronomical environmental disaster.

Prior to this, the author carried out a dark sky survey of the Malvern Hills area of outstanding natural beauty (AONB), relating it to the same light pollution model. The results confirm the general predictions of the model and also clearly illustrate the relative significance of different designs of light sources at different distances, to the dark sky environment.

The paper also briefly describes the results from the same model adapted to study the night-time environmental impact of a proposed very large sea based wind farm project in the English Channel, as a part of the planning process.

Christopher Baddiley

AUTHORS/INSTITUTIONS: C.J. Baddiley, None, Retired physisicst, BAA Campaign for Dark skies, Mathon (Nr. Malvern), UNITED KINGDOM

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