Landscape Architect & Specifier News

APR 2013

LASN is a photographically oriented, professional journal featuring topics of concern and state-of-the-art projects designed or influenced by registered Landscape Architects.

Issue link: https://landscapearchitect.epubxp.com/i/120967

Contents of this Issue

Navigation

Page 17 of 149

ordinances Lighting Design: Considering the Impacts of Light Pollution (Dark Sky) ���The problems of light pollution first became an issue in the 1970s when astronomers identified the degradation of the night sky due to the increase in lighting associated with development and growth. As more impacts to the environment by lighting have been identified, an international ���dark sky��� movement is advocating for the precautionary approach to outdoor lighting design.��� ��� Model Lighting Ordinance The International Dark-Sky Association (IDA) www.darksky.org has a ���Glare Metrics��� program www.darksky. org/outdoorlighting/83light-pollution-research, a joint effort between IDA and Ian Lewin, of Lighting Sciences, Inc. This program is designed to create a standard of accurately and uniformly measuring glare, primarily by looking at intensity, luminance, and luminance contrast. by Yvonne English, RLA, LEED AP, ASLA, IDA, IES What is light pollution? It's any adverse effects resulting from not properly shielded outdoor lighting. An unshielded light source allows light directed where it is not wanted���into people���s eyes and the night sky. There are four forms of light pollution: Sky glow: light shining into the night sky above the horizon. This is the brightening of the night sky by artificial light. Contributors are uplighting and reflected light. Light trespass: light directed into areas where it is not intended, wanted, or needed, such as poorly shielded or poorly aimed fixtures. Glare: light that shines into our eyes, causing visual discomfort and decreased visibility. Clutter: a combination of all three, bright, confusing, and excessive groupings of light sources, commonly found in over-lit urban areas Why Is Light Pollution a Threat? Light pollution causes multiple issues. Some are obvious, but many are not, and not easily related to light pollution. The obvious threats: 1. Our views of the skies have drastically changed over the past 60 years. The view from a mountain top may be similar to night sky views from the 1950s, but the views of the urban skies are much different. The children's song "Twinkle, Twinkle, Little Star" has little meaning during the night in urban cities. Views are impacted primarily by the sky glow and clutter of artificial light. 18 Landscape Architect and Specifier News 2. Light trespass is a violation of property rights. An example is the typical spot light on the side of a home, which usually produces light that crosses into the neighbor's property. Such lighting can penetrate bedroom windows and disrupt sleep. 3. Our safety is greatly impacted by glare, which can temporarily blind people, particularly youngsters and the elderly. Glare is harmful, not protecting. Our health, the health of wildlife (which impacts the health of our planet) and wasted energy are the less understood threats of light pollution. How does light pollution impact our health? Light affects our natural circadian biological rhythms, which in turn impacts our health. In 2012, the American Medical Association issued a report on the health effects of light pollution, which in part stated: "The natural 24-hour cycle of light and dark helps maintain precise alignment of circadian biological rhythms, the general activation of the central nervous system and various biological and cellular processes, and entrainment of melatonin release from the pineal gland. Pervasive use of nighttime lighting disrupts these ... processes and creates potentially harmful health effects ..." The report further states: ���More direct health effects of nighttime lighting may be attributable to disruption of the sleep-wake cycle and suppression of melatonin release. Even low intensity nighttime light has the capability of suppressing melatonin release. In various laboratory models of cancer, melatonin serves as a circulating anticancer signal and suppresses tumor (Continued on page 96)

Articles in this issue

Links on this page

Archives of this issue

view archives of Landscape Architect & Specifier News - APR 2013