The lighting in the city centres Light pollution
Urban lighting masterplans
The objectives of this study
44 URBAN LIGHTING
The first purpose of artificially lighting the cities was mainly functional, that of providing safety at night and extending the normal activities beyond the sun-set. Still today, this seems to be one the main objectives when implementing lighting. For example, The Royal Comission on Environmental Pollution75 considers that “the purpose of most outdoor lighting is to enable people to go safely and securely about their business on the ground”(…) “There is a demand for outdoor lighting for road safety, personal security against crime, and evening social and commercial activities.”76
However, many cities have already acknowledged, that artificial lighting can have a wider role, involving the improvement of several other night-time urban aspects. The LUCI77 charter on urban lighting78, for example, states the importance that well designed lighting may have in the urban development and regeneration.
Lighting can be interpreted as an instrument of urban planning since ancient times.
There are several examples of the role that the sun had in the urban design of numerous civilizations, from ancient Roman to pre-Columbian cities. However, for centuries, artificial lighting was mainly associated to practical needs, such as safety, or to royal and aristocratic festivities79.The danger involved in the use of combustive materials and its maintenance cost prevented an effective lighting policy until the invention of gas and electricity lighting. Thus, until the end of the nineteen century lighting was very scarce and restricted to small areas. Today lighting is available to
75 (The Royal Comission on Environmental Pollution, 2009)
76 Ibid. p.9
77 Lighting Urban Community International
78 (Lighting urban community International, 2010)
79 (Neuman, 2002), (O'Dea, 1958), (Dillon, 2002)
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everyone and implanted almost everywhere. This “lighting democratization” is positive, but it also has disadvantages.
For example, street lighting, in the UK alone, accounts for some 450MW of installed load, resulting in 1 million tons of CO2 emissions per annum and is responsible for considerable light pollution80. Light pollution can take various forms, such as glare, light trespass and sky glow. Moreover, it may have pernicious effects on flora, fauna, and human health.81 There are, however, regulations and equipment designed to control the projection of light into the atmosphere.
Lighting has also an impact on economy, through expensive energy consumption, leading some authorities to consider measures as strong as restricting its use during certain periods of the night82. Less drastic measures include adopting dimmable lighting, or restricting the time during which monuments are lit83. There are also authorities that are investing largely in new technologies, such as LED street lighting84, and/or in alternative energy sources, such as solar, wind, or tides85.
80 (Mansfield & Raynham, 2005)
81 (The Royal Comission on Environmental Pollution, 2009)
82 For example the county of Shropshire, in the West Midlands region of England, Swansea, Essex, Leicestershire, Devon and parts of Yorkshire in: http://www.bbc.co.uk/news/uk-england-shropshire-11210468, and http://www.bbc.co.uk/news/uk-11209143 accessed in September 2010.
83 For example, in Lisbon, Barcelona, Geneva, Lion and Paris most Monuments are turned off around midnight, and have different schedules for summer and winter time. (information gathered in Lisbon light department, and http://www.ecodallecitta.it/notizie.php?id=417 last accessed in 2007.
84Such as several cities in the United States and in Europe.
85According to the European Union's official research and innovation information service, the use of photovoltaic panels have been growing rapidly in Europe, with Germany as the leading country in the application of this technology.
http://cordis.europa.eu/fetch?caller=en_news_fp7&action=d&doc=1&cat=news&query=012aec4cfb15:b828:56533b 09&rcn=32488 accessed in September 2010
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The advantages of having a lit environment that enables a visible and safe environment during the night-time surpasses the disadvantages. Otherwise there would not be any artificially lit cities at all. But given the current concerns with reducing energy consumption, will the purpose and the way of artificially lighting the cities remain the same?
It can be speculated that the concern with energy savings will lead to the new and more efficient technologies and alternative energy sources having an increasingly important role in lighting. However, careful planning of urban lighting may also have a significant part in reducing energy costs while improving the quality of the night-time environments. In the last twenty years, a great number of lighting masterplans were developed and implemented, mostly in Europe, and also in other parts of the world.
Some of these masterplans, and particularly those from recent years, include in its objectives environmental and economic goals. A survey on the role and objectives of lighting masterplans will be presented further ahead. Before, there will be a brief review of the problems related to lighting in historical city centres and on light pollution.
47 THE LIGHTING IN CITY CENTRES
Lighting heritage or historical centres can be a complex task and should probably entail a reflection on several questions. First, because most heritage precedes the invention of electricity, it is difficult to determine how to light such environments.
Mainly, because any lighting intervention will result in an interpretation of a space or building whose image should be protected. There are those who advocate that the original image of such an environment, which is its day-time appearance, should be maintained at all cost86. Others87 defend that, since it is almost impossible to reproduce daylight, a subjective interpretation should always take place. Secondly, historical urban areas and heritage buildings are especially important to the cultural identity of a city. Thus, many are protected by entities that issue recommendations and regulations to ensure its protection. Lighting should comply with specific heritage recommendations and regulations that may apply. The International Council on Monuments and Sites (ICOMOS) defends in its publications88 the relationships between buildings:
“The qualities to be preserved include the historic character of the town or urban area and all of those material and spiritual elements that express this character, especially: Urban patterns as defined by lots and streets, relationships between buildings and green and open spaces, the formal appearance of buildings (…), the relationship between the urban area and its surrounding setting.”89
The relationship between monument and its context is one of the main principles of historical centres conservation, and lighting should be planned according to this
86 (Ginesi, 2000)
87 For example, (Ravizza, 2006)
88 (International Council on Monuments and Sites, 1965) ( International Council on Monuments and Sites, 1987) (International Council on Monuments and Sites, 2000)
89 ( International Council on Monuments and Sites, 1987)p.11
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premise. Terzi90 describes light as a substantial component of requalification and restoration due to its capacity to enhance details, rebuild the relations between ensembles and allowing selecting what will be visible or invisible during the night time.