Light Pollution Modeling

Light pollution is a common issue in urban areas. It is an especially sensitive topic for densely populated metropolises such as Hong Kong. In order to control and reduce light pollution effects, appropriate analysis and measures must be undertaken for new constructions and major renovations.

The main components of light pollution are night sky glow, trespassing light into windows of sensitive receivers, source intensity and building facade luminance. We offer an integrated exterior lighting simulation, which evaluates the implications of the proposed design and gives us important information about the performance of each of the key parameters.

Sky Glow – this is the glow effect of all light emitted and reflected into the sky which is then scattered by the atmosphere and redirected back to the earth.

Light Trespass – this is all the light that escapes the site boundary and enters the neighbouring properties. The most critical aspect is the light into the windows of residential, healthcare buildings and other sensitive receivers.

Source Intensity – this is the intensity going beyond the area being lit from any single source in the potentially obtrusive direction.

Over-illuminance – includes all surfaces which receive artificial lighting at night (building facade lit by facade lighting but also others such as walkways, roads, landscape features, etc.). A part of this light is reflected into potentially obtrusive directions.

We evaluate the performance of the proposed design by referring to leading international standards such as the International Commission on Illumination – Guide on the limitation of the effects of obtrusive light from outdoor lighting installations. Technical Report CIE 150:2003 and CIBSE – Environmental Considerations for Exterior Lighting, Fact-file no. 7.

Light pollution modeling is valuable for architects, lighting consultants and landscape architects. At AEE we work closely with these professionals and optimize the exterior lighting design by advising on location, direction, shading options, reflectors and light fittings selection.