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Light Pollution

Introduction

Lighting and particularly excessive lighting is becoming an increasing issue and nuisance for many. However, we all expect security and adequate facilities for leisure.

Light Pollution is excessive levels of lighting provision and 'spillage' from lighting installations. It is caused by:

Sky Glow - The scattering of artificial light by dust particles and water droplets in the sky, and relates to the level of air pollution;
Glare - An intense blinding light;
Spill - The 'overflow' of artificial light beyond the area subjected to lighting.

In many cases all three elements will coincide and be visible from many miles away. Other aspects include building luminance (the reflected light from the surface of a building) and wasted energy consumption.

There is a close relationship between the intensity of lighting and urban areas, but there is increasing concern about the advance of light into traditionally 'dark' rural landscapes. The Institution of Lighting Engineers have identified four Environmental Zones based upon sensitivity to light:

In 1994 Dacorum Borough Council organised a seminar relating to Exterior Lighting and Planning. In 1996 the Department of the Environment organised a Light Pollution Seminar and published with the Countryside Commission 'Lighting in the countryside: Towards good practice' (1997). The Crime and Prevention Act 1998 refers to lighting for safety and security, but light pollution is not recognised by the Environmental Protection Act 1990.

Measurement and monitoring of light pollution is difficult as there is little or no recorded data upon which to assess changes over time.

Floodlighting in Hertfordshire-Current Trends

The level of increase in floodlighting over recent years was crudely measured by reviewing planning applications for 1996 and part of 1999.

This analysis indicates that there may have been an increase in floodlighting applications of around 60% in 4 years.

Most applications are for sporting facilities, reflecting expectation of increased access to and high standards of sport, in addition to healthier lifestyles.

Impact on the Green Belt-implying increased urbanisation of the countryside-is a consistent reason for refusal. 74% of applications are approved but most include conditions to control the extent of artificial lighting. The exceptions were lighting of buildings for security or amenity. Most limitations (80%) apply to hours of use during any 24 hour period.

Policies for Light Pollution - National and Local

The Planning Officers Society (1997) produced guidance for a model policy and it is addressed in Hertfordshire County Council's Structure Plan Review (1991-2011). Current reviews of Local Plans also include light pollution within policies and their justification, so it is clear that floodlighting is being considered by most authorities in the county as part of the planning process.

Are we Working in the Dark?

The information above does not show the whole range of applications including exterior lighting or the extent of floodlighting in Hertfordshire but it does demonstrate a trend. If demand for use of such facilities also increases, this may become a significant problem, especially in rural locations.

This highlights the urgent need for more information on the issue to help with the determining of individual planning applications, which need to be made against an understanding of the situation in the local area.

Local Planning Authorities in Hertfordshire are aware of the issue and are including it within the planning policy and development control framework. The ecological implications of extreme lighting are very profound, impacting upon nature's most fundamental rhythms of day and night. Nevertheless, with a responsible approach we can hopefully ensure that the moon hasn't cast its last shadow in Hertfordshire quite yet.

For further information contact: Martin Hicks, Biological Records Centre, Hertfordshire County Council, 01992 555220 or Nigel Gibbs, Dacorum Borough Council, 01442 228576