Asbestos and Asbestos Health Effects
What is asbestos?
Asbestos is the name given to a number of naturally occurring fibrous minerals with high tensile strength, the ability to be woven, and resistance to heat and most chemicals. Because of these properties, asbestos fibers have been used in a wide range of manufactured goods, including roofing shingles, ceiling and floor tiles, paper and cement products, textiles, coatings, and friction products such as automobile clutch, brake and transmission parts. The current federal definition of asbestos is the asbestiform varieties of: chrysotile (serpentine); crocidolite (riebeckite); amosite (cummingtonite/grunerite); anthophyllite; tremolite; and actinolite.
What are the health effects of asbestos exposure?
Exposure to airborne friable asbestos may result in a potential health risk because persons breathing the air may breathe in asbestos fibers. Continued exposure can increase the amount of fibers that remain in the lung. Fibers embedded in lung tissue over time may cause serious lung diseases including: asbestosis, lung cancer, or mesothelioma. Smoking increases the risk of developing illness from asbestos exposure.
Three of the major health effects associated with asbestos exposure include: • Asbestosis – Asbestosis is a serious, progressive, long-term non-cancer disease of the lungs. It is caused by inhaling asbestos fibers that irritate lung tissues and cause the tissues to scar. The scarring makes it hard for oxygen to get into the blood. Symptoms of asbestosis include shortness of breath and a dry, crackling sound in the lungs while inhaling. There is no effective treatment for asbestosis.

• Lung Cancer – Lung cancer causes the largest number of deaths related to asbestos exposure. People who work in the mining, milling, manufacturing of asbestos, and those who use asbestos and its products are more likely to develop lung cancer than the general population. The most common symptoms of lung cancer are coughing and a change in breathing. Other symptoms include shortness of breath, persistent chest pains, hoarseness, and anemia.

• Mesothelioma – Mesothelioma is a rare form of cancer that is found in the thin lining (membrane) of the lung, chest, abdomen, and heart and almost all cases are linked to exposure to asbestos. This disease may not show up until many years after asbestos exposure. This is why great efforts are being made to prevent school children from being exposed.

Exposure to asbestos increases your risk of developing lung disease. That risk is made worse by smoking. In general, the greater the exposure to asbestos, the greater the chance of developing harmful health effects. Disease symptoms may take several years to develop following exposure. If you are concerned about possible exposure, consult a physician who specializes in lung diseases (pulmonologist). • Occupational Safety and Health Administration (OSHA) - An estimated 1.3 million employees in construction and general industry face significant asbestos exposure on the job. Heaviest exposures occur in the construction industry, particularly during the removal of asbestos during renovation or demolition. Employees are also likely to be exposed during the manufacture of asbestos products (such as textiles, friction products, insulation, and other building materials) and during automotive brake and clutch repair work. Asbestos is well recognized as a health hazard and is highly regulated. OSHA and EPA asbestos rules are intertwined.

This factory still stands in Bhopal like a hoary symbol of the worst tragedy of the industrial era. The Union Carbide factory and the face of then Union Carbide chairman Warren Anderson remained etched in the memory of millions of Indians as mascots of all that is wrong with transnational industrial corporations.
Surrounding the skeletal remains of the pesticide factory are maimed survivors of the nuclear winter of what a poet has called DeathSmog Day. After 20 years, there are as many questions unanswered as the number of people who have died since that fateful day.
Death seeped into the lives of Bhopal residents in the form of a white cloud. Methyl isocyanate gas leaked from the factory, affecting more than 500,000 people. Estimates say 7,000 people died within three days of the gas leak. Thousands have died since, many permanently maimed. The genetic and psychological scars threaten to take their toll on generations to come.
How did the factory's accident management systems fail? More importantly, who is to blame? Why, after 20 years, has the Indian government still not disbursed full aid to all the victims? Who is accountable for thousands of people having been denied the right to decent living due to procedural delays?
Thousands of children died or were permanently disabled. Investigations in the affected areas have revealed that 70 per cent of the children born before the disaster continue to suffer from respiratory diseases and 55 per cent from affected eyesight. Children born after the disaster have not been spared. Doctors warn worse effects remain to be seen. Parents are likely to pass on genetic aberrations caused by inhaling the noxious fumes to their children -- through breast milk and genetically. The terrible incident threatens to engender a generation of 'Carbide children', who will carry forward the toxic legacy of their parents in the form of genetic disorders.

About 120,000 to 150,000 residents of Bhopal continue to be ill. Clinics report a regular stream of patients complaining of diseases of the eyes, lungs, kidneys, liver, brain, reproductive and immune systems. The rate of TB among people exposed to the gas is four times higher than the national average, statistics gleaned from clinics revealed.
After the accident, many pregnant women suffered miscarriages, while others delivered still born or malformed babies. More than half the children exposed to the gas in their mothers' wombs died. Many others were born with deformities. In the post-gas era, such children were called 'gas kand ke bacchche, or 'Carbide children.'
Another terrifying condition is what one doctor called 'menstrual chaos' amongst women exposed to the gas. Among the problems that were reported were early menopause (some as early as age 27) and short and painful menstrual cycles. Bhopal is an unprecedented human rights tragedy. NGOs and gas victims' organisations have continued a relentless campaign to pressure the government, Union Carbide India Limited and Dow Chemicals to recognise the fact that compensation means more than just an aid package.
For instance, 20 years after the incident, Bhopal residents remain at risk of poisoning due to toxic material still stocked around the plant. Ground water tests have shown contamination levels hundreds of times higher than World Health Organisation limits. Union Carbide has questioned the test results, saying there is no evidence of ground water contamination outside the plant when it handed the site back to the state government in 1998.
It is up to the government to end the humanitarian crisis. As Amnesty International urged in a report released to coincide with the 20th anniversary of the tragedy, the authorities need to do an exhaustive assessment of the environmental and medical fallout from the incident. Or it risks creating another generation that will relive December 2-3, 1984 every day of their lives.

What readers commend about Bhopal Tragedy :
Bhopal Gas tragedy is a tragic reminder of the callousness of the collective Indian Psyche.It exposed the naked truth that our so called democracy does not have any room for the downtrodden-those who really suffered and instead did everything best to ptotect MNC's like Union Carbide or its successor like DOW Chemicals.
I was not aware at the time when this tragedy took place,since I was 2 year old child.But have heard so much about this tragedy,which makes me to feel angry on the US firms.It has been said that the Firm (Union Carbide)that is purely responsible for this tragedy has shown double standards in the safety arrangements made in it's factory in USA and in INDIA.And even now it says that it's not fully liable for that tragedy. This shows how the international laws are inadequate to bring justice. What will happen if the same has happened in USA in an Indian firms factory? The US departments would say this and that and will reach out inside India to close it factory in India also. I think the Indian government would here after take all the necessary steps to safe guard it citizens from these type of stupid firms.
And I feel very sad and pray to GOD that these tragedies should not happen ever again.
I think US company owes a lot of compensation to the poeple of Bhopal for their negligence on security measures and their irresponsiveness towards the tragedy. Above all US are still holding the fugitive Anderson who has missed trial in India on mass slaughter and still walking free in Florida. If lives of US people are valuable and so our the lives of our beloved people. I really admire those that are taking the initiative to bring justice to the people of Bhopal who are still bearing the consequences of the deadly MIC poison.
World's worst Industrial disaster, worlds worst train disaster, worlds worst Road record worlts worrst etc etc... and the list goes on.. whom to blame? India and its people. People learn by their mistake but "WE" dont...Its "sab chalta hai" style. If you look deep there are rumours that it was the work of American government who did it intentionally to check the effect of this lethal gas. where the hell was MP governement when a chemical plant was opened right in the heart of city? where the hell is our CID or these intellegance agency who couldnt find the REAL culprit? Imagine if there was an opposite situation an Indian firm was responsible such unjustiable event in some US cities like Denver..what were the consequences? still Americans are allowed to put pestisides in Coke manufactures in India itself. I am not surprised if there are some more of these tragedies happens. God bless India!

Effects of the Bhopal Tragedy
Bhopal: 20-years on, the gas tragedy survivors in Bhopal are demanding free treatment for their children and a monthly pension of Rs1,000 from the state government.
The survivors argued that exposure to the toxic gases from the Union Carbide plant led to birth defects among children in the area.
The Bhopal tragedy occurred on the night of Dec 2, 1984, when over 40 tonnes of lethal methyl iso-cyanate (MIC) leaked out of the pesticide plant—one of worst industrial accident that killed over 3,000 people and left long-lasting defects on the survivors and their generations. Over 15,000 people affected by exposure have died since then.

One of the activists said, "These children suffer from cerebral palsy, cleft lip, missing palate and disabilities related to vision, hearing and mental disorders. Their numbers could increase if an in-depth survey is conducted."

Medical specialists from Delhi and Bhopal, at a health camp in December 2006, confirmed the presence of several birth defects caused by pesticides, chemicals and heavy metals in the groundwater in and around the abandoned Union Carbide factory.
Studies by the MP Pollution Control Board have also shown that pesticides such as endrin, dieldrin, carbaryl, methoxychlor that can cause birth defects are still present in the groundwater samples collected from the area.

Bernardino Ramazzini (1633-11-03 - 1714-11-05) was an Italian physician.
Born in Carpi, Ramazzini was an early proponent of the use of cinchona bark (from which quinine is derived) in the treatment of Malaria. His most important contribution to medicine was his work on occupational diseases called De Morbis Artificum Diatriba (Diseases of Workers) which outlined the health hazards of chemicals, dust, metals, and other agents encountered by workers in 52 occupations. This was one of the founding and seminal works of occupational medicine and played a substantial role in its development. He served as professor of medicine at the University of Padua from 1700 until his death.
In regards to malaria, Ramazzini was one of the first to support the use of the quinine-rich bark cinchona. Many falsely claimed that quinine was toxic and ineffective, but Ramazzini recognized its importance. He is quoted, "It [quinine] did for medicine what gun powder did for war."[1]
He died in Padua in 1714.

Occupational Disease
The term "occupational disease" refers to those illnesses caused by exposures at the workplace. They should be separated, conceptually, from injuries that may also occur at workplaces due to a variety of hazards.
In 2001, some 137 million Americans were working, either full-time or part-time, out of a total population of some 280 million. Women make up 46 percent of the workforce.
Occupational diseases may occur in varying time frames, from the instantaneous development of illness following exposure to toxic chemicals to decades between onset of exposure and the development of disease, as occurs with many occupationally related cancers. Many time frames in between these extremes may be seen as well. Examples of varying time frames include instantaneous reactions to exposure to chemicals such as chlorine or ammonia gas; a delay of some six to twelve hours with fumes of aerosolized zinc, as occurs when welding on galvanized steel; a delay of weeks to months with lead poisoning; a delay of decades with occupational carcinogens; and even the finding of congenital malformations in children whose parents may have been exposed to hazardous materials.

Noise pollution
Noise pollution (or environmental noise) is displeasing human- or machine-created sound that disrupts the activity or balance of human or animal life. A common form of noise pollution is from transportation, principally motor vehicles.[1] The word "noise" comes from the Latin word nausea meaning "seasickness", referring originally to nuisance noise.[2
The source of most noise worldwide is transportation systems, motor vehicle noise, but also including aircraft noise and rail noise.[3][1] Poor urban planning may give rise to noise pollution, since side-by-side industrial and residential buildings can result in noise pollution in the residential area.
Other sources are office equipment, factory machinery, construction work, appliances, power tools, lighting hum and audio entertainment systems.
Noise health effects are both health and behavioral in nature. The disliked sound is called sound noise. This unwanted sound can damage physiological and psychological health. Noise pollution can cause annoyance and aggression, hypertension, high stress levels, tinnitus, hearing loss, sleep disturbances, and other harmful effects.[4][5][6] Furthermore, stress and hypertension are the leading causes to health problems, whereas tinnitus can lead to forgetfulness, severe depression and at times panic attacks.[5][7]
Chronic exposure to noise may cause noise-induced hearing loss. Older males exposed to significant occupational noise demonstrate significantly reduced hearing sensitivity than their non-exposed peers, though differences in hearing sensitivity decrease with time and the two groups are indistinguishable by age 79.[8] A comparison of Maaban tribesmen, who were insignificantly exposed to transportation or industrial noise, to a typical U.S. population showed that chronic exposure to moderately high levels of environmental noise contributes to hearing loss.[4]
High noise levels can contribute to cardiovascular effects and exposure to moderately high levels during a single eight hour period causes a statistical rise in blood pressure of five to ten points and an increase in stress[9] and vasoconstriction leading to the increased blood pressure noted above as well as to increased incidence of coronary artery disease.
Noise pollution is also a cause of annoyance. A 2005 study by Spanish researchers found that in urban areas households are willing to pay approximately four Euros per decibel per year for noise reduction.[10]

[edit] Health effects of aircraft noise

Main article: Noise health effects
The annoyance effects of aircraft noise are widely recognized; however, aircraft noise is also responsible for a significant amount of hearing loss as well as a contributor to a number of diseases. Only in the early 1970s did aircraft noise become a widespread topic of concern in the U.S. and federal regulations began to recognize the significance of abating these impacts in the vicinity of major commercial airports. High levels of aircraft noise that may exist near major commercial airports are known to increase blood pressure and contribute to hearing loss. Some research indicates that it contributes to heart diseases, immune deficiencies, neurodermatitis, asthma and other stress related diseases. Further research is being carried out to better understand these effects.
Research indicates that hearing loss is less a product of aging than a result of exposure to transportation related noise (Rosen, 1965). Any sound louder than normal conversation can damage the delicate hair cells in the cochlea, the structure in the inner ear that converts sound waves into auditory nerve signals. Initially damage to the cochlea may be temporary, but with repeated exposure, the damage becomes permanent and tinnitus may develop. More recently the Centers for Disease Control and Prevention's (CDC) National Center for Environmental Health (NCEH) conducted an analysis to determine the prevalence of hearing loss among children using data collected from 1988-1994 in the Third National Health and Nutrition Examination Survey. The analysis indicates that 14.9% of U.S. children have low or high frequency hearing loss of at least 16 dB hearing level in one or both ears.
From research of the National Institutes of Health, roughly 65 million Americans are exposed to sound levels that can interfere with their function at work or disrupt sleep, and 25 million are exposed to health risk (cardiovascular, immunological, etc.) from environmental noise.

[edit] Noise mitigation programs

Main article: Noise mitigation
In the United States, since aviation noise became a public issue in the late 1960s, governments have enacted legislative controls. Aircraft designers, manufacturers, and operators have developed quieter aircraft and better operating procedures. Modern high-bypass turbofan engines, for example, are quieter than the turbojets and low-bypass turbofans of the 1960s. First, FAA Aircraft Certification achieved noise reductions classified as 'Stage 3' aircraft; which has been upgraded to 'Stage 4' noise certification resulting in quieter aircraft. This has resulted in lower noise exposures in spite of increased traffic growth and popularity.
In the 1980s the U.S. Congress authorized the FAA to devise programs to insulate homes near airports. While this does not address the external noise, the program has been effective for residential interiors. Some of the first airports at which the technology was applied were San Francisco International Airport and San Jose International Airport in California. A computer model is used which simulates the effects of aircraft noise upon building structures. Variations of aircraft type, flight patterns and local meteorology can be studied. Then the benefits of building retrofit strategies such as roof upgrading, window glazing improvement, fireplace baffling, caulking construction seams can be evaluated.(Hogan, 1984).
Another idea to reduce aircraft noise on communities is floating airports which would be situated many miles out to sea. There are major drawbacks to this solution including expense, time and inconvenience to travelers in reaching such an airport. This includes the inability to integrate at-sea-airports with transport networks or proximity to business and cargo infrastructure.

[edit] Night flying restrictions

At Heathrow, Gatwick and Stansted airports in the UK, and Frankfurt Airport in Germany, night flying restrictions apply to reduce noise exposure at night.[2][3] 1. ^ a b "Aircraft Airframe Noise - Research Overview". Retrieved on 2008-07-13. 2. ^ Dept for Transport (June 2006). "Night flying restrictions at Heathrow, Gatwick and Stansted Airports". Retrieved on 2008-07-12. 3. ^ Dept for Transport (undated). "Night restrictions at Heathrow, Gatwick and Stansted (second stage consultation)". Retrieved on 2008-07-12. • C. Michael Hogan and Jorgen Ravnkilde, Design of acoustical insulation for existing residences in the vicinity of San Jose Municipal Airport, January 1, 1984, FAA grant funded research, ISBN B0007B2OG0 • U.S. Noise Control Act of 1972 United States Code Citation: 42 U.S.C. 4901 to 4918 • S. Rosen and P. Olin, Hearing loss and coronary heart disease, Archives of Otolaryngology, 82:236 (1965)

Mitigation and control of noise

Main article: Noise mitigation
[pic]
[pic]
The sound tube in Melbourne, Australia, designed to reduce roadway noise without detracting from the area's aesthetics.

Technology to mitigate or remove noise can be applied as follows:
There are a variety of strategies for mitigating roadway noise including: use of noise barriers, limitation of vehicle speeds, alteration of roadway surface texture, limitation of heavy duty vehicles, use of traffic controls that smooth vehicle flow to reduce braking and acceleration, and tyre design. An important factor in applying these strategies is a computer model for roadway noise, that is capable of addressing local topography, meteorology, traffic operations and hypothetical mitigation. Costs of building-in mitigation can be modest, provided these solutions are sought in the planning stage of a roadway project.
Aircraft noise can be reduced to some extent by design of quieter jet engines, which was pursued vigorously in the 1970s and 1980s. This strategy has brought limited but noticeable reduction of urban sound levels. Reconsideration of operations, such as altering flight paths and time of day runway use, have demonstrated benefits for residential populations near airports. FAA sponsored residential retrofit (insulation) programs initiated in the 1970s has also enjoyed success in reducing interior residential noise in thousands of residences across the United States.
Exposure of workers to Industrial noise has been addressed since the 1930s. Changes include redesign of industrial equipment, shock mounting assemblies and physical barriers in the workplace.

Noise mitigation

From Wikipedia, the free encyclopedia

Jump to: navigation, search
Noise mitigation is a set of strategies to reduce noise pollution. The main areas of noise mitigation or abatement, are: transportation noise control, architectural design, and occupational noise control. Roadway noise and aircraft noise are the most pervasive sources of environmental noise worldwide, and remarkably little change has been effected in source control in these areas since the start of the problem, a possible exception being the development of the hybrid vehicle.
Multiple techniques have been developed to address interior sound levels, many of which are encouraged by local building codes; in the best case of project designs, planners are encouraged to work with design engineers to examine tradeoffs of roadway design and architectural design. These techniques include design of exterior walls, party walls and floor/ceiling assemblies; moreover, there are a host of specialized means for dampening reverberation from special purpose rooms such as auditoria, concert halls, dining areas and meeting rooms. Many of these techniques rely upon materials science applications of constructing sound baffles or using sound absorbing liners for interior spaces. Industrial noise control is really a subset of interior architectural control of noise, with emphasis upon specific methods of sound isolation from industrial machinery and for protection of workers at their task stations.

Roadway noise mitigation

[pic]
[pic]
This Hybrid vehicle can operate 15 to 25 decibels more quietly than conventional autos at speeds less than 60 km/h

Source control in roadway noise has provided little reduction in vehicle noise, except for the development of the hybrid vehicle; nevertheless, hybrid use will need to attain a market share of roughly fifty percent to have a major impact on noise source reduction on city streets. (Highway noise is little affected by automobile type, since those effects are aerodynamic and tyre noise related.) Other contributions to reduction of noise at the source are: improved tire tread designs for trucks in the 1970s, better shielding of diesel stacks in the 1980s, and local vehicle regulation of unmuffled vehicles.
The most fertile area for roadway noise mitigation is in urban planning decisions, roadway design, noise barrier design[1], speed control, surface pavement selection and truck restrictions. Speed control is effective since the lowest sound emissions arise from vehicles moving smoothly at 30 to 60 kilometres per hour. Above that range sound emissions double with each five miles per hour of speed. At the lowest speeds, braking and (engine) acceleration noise dominates. Selection of surface pavement can make a difference of a factor of two in sound levels, for the speed regime above 30 kilometres per hour. Quieter pavements are porous with a negative surface texture and use medium to small aggregates; the loudest pavements have a transversely tined/grooved surface, and/or a positive surface texture and use larger aggregates. Obviously surface friction and roadway safety are important considerations as well for pavement decisions.
When designing new urban freeways or arterials, there are numerous design decisions regarding alignment and roadway geometrics[2], Use of a computer model to predict future sound levels from line sources has become standard practice since the early 1970s. In this way exposure of sensitive receptors to elevated sound levels can be minimized. An analogous process exists for urban mass transit systems and other rail transportation decisions. Early examples of urban rail systems designed using this technology were: Boston MTA line expansions (1970s), San Francisco Bay Area Rapid Transit System expansion (1981), Houston light rail system (1982), Portland, Oregon Beaverton light rail line (1983).
Noise barriers can be applicable for existing or planned surface transportation projects. They are probably the single most effective weapon in retrofitting an existing roadway, and commonly can reduce adjacent land use sound levels by ten decibels. A computer model is required to design the barrier since terrain, micrometeorology and other locale specific factors make the endeavor a very complex undertaking. For example, a roadway in cut or strong prevailing winds can produce a setting where atmospheric sound propagation is unfavorable to any noise barrier.

[edit] Aircraft noise abatement

[pic]
[pic]
A British Airways Airbus A321, on landing approach to London Heathrow Airport, showing proximity to homes.

As in the case of roadway noise, surprisingly little progress has been made in quelling of aircraft noise at the source, other than elimination of loud engine designs from the 1960s and earlier. Because of its velocity and volume, jet turbine engine exhaust noise defies reduction by any simple means. The most promising forms of aircraft noise abatement is through land planning, flight operations restrictions and residential soundproofing. Flight restrictions can take the form of preferred runway use; departure flight path and slope; and time of day restrictions. These tactics are sometimes controversial since they can impact aircraft safety, flying convenience and airline economics.
In 1979 the U.S. Congress authorized[3] the FAA to devise technology and programs to attempt to insulate homes near airports. While this obviously does not aid the exterior environment, the program has been effective for residential and school interiors. Some of the first airports at which the technology was applied were San Francisco International Airport[4], Seattle-Tacoma International Airport, John Wayne International Airport and San Jose International Airport[5] in California. The underlying technology is a computer model which simulates the propagation of aircraft noise and its penetration into buildings. Variations in aircraft types, flight patterns and local meteorology can be analyzed along with benefits of alternative building retrofit strategies such as roof upgrading, window glazing improvement, fireplace baffling, caulking construction seams and other measures. The computer model allows cost effectiveness evaluations of a host of alternative strategies.

Architectural solutions

Main article: Architectural acoustics
Beyond the interior acoustics cited above under aircraft noise, there has been a steady trend to design quieter buildings with regard to sources within and without the structure itself. In the case of construction of new (or remodeled) apartments, condominiums, hospitals and hotels many states and cities have stringent building codes with requirements of acoustical analysis, in order to protect building occupants. With regard to exterior noise, the codes usually require measurement of the exterior acoustic environment in order to determine the performance standard required for exterior building skin design. The architect can work with the acoustical scientist to arrive at the best cost effective means of creating a quiet interior (normally 45 dBA). The most important elements of design of the building skin are usually: glazing (glass thickness, double pane design etc.), roof material, caulking standards, chimney baffles, exterior door design, mail slots, attic ventilation ports and mounting of through the wall air conditioners.
Regarding sound generated inside the building, there are two principal types of transmission. Firstly, airborne sound travels through walls or floor/ceiling assemblies and can emanate from either human activities in adjacent living spaces or from mechanical noise within the building systems. Human activities might include voice, amplified sound systems or animal noise. Mechanical systems are elevator systems, boilers, refrigeration or air conditioning systems, generators and trash compactors. Since many of these sounds are inherently loud, the principal design element is to require the wall or ceiling assembly to meet certain performance standards[6] (typically Sound transmission class of 50), which allows considerable attenuation of the sound level reaching occupants.
The second type of interior sound is called Impact Insulation Class (IIC) transmission. This effect arises not from airborne transmission, but rather from transmission of sound through the building itself. The most common perception of IIC noise is from footfall of occupants in living spaces above. This type of noise is more difficult to abate, but consideration must be given to isolating the floor assembly above or hanging the lower ceiling on resilient channel.
Both of the above transmission effects may emanate either from building occupants or from building mechanical systems such as elevators, plumbing systems or heating, ventilating and air conditioning units. In some cases it is merely necessary to specify the best available quieting technology in selecting such building hardware. In other cases shock mounting of systems to control vibration may be in order. In the case of plumbing systems there are specific protocols developed, especially for water supply lines, to create isolation clamping of pipes within building walls. In the case of central air systems, it is important to baffle any ducts that could transmit sound between different building areas.
Designing special purpose rooms has more exotic challenges, since these rooms may have requirements for unusual features such as concert performance, sound studio recording, lecture halls. In these cases reverberation and reflection must be analyzed in order to not only quiet the rooms but prevent echo effects from occurring. In these situations special sound baffles and sound absorptive lining materials may be specified to dampen unwanted effects..

[edit] Industrial noise mitigation

This situation classically is thought to involve primarily manufacturing settings where industrial machinery produces intense sound levels[7], not uncommonly in the 75 to 85 decibel range. While this circumstance is the most dramatic, there are many other office type environments where sound levels may lie in the range of 70 to 75 decibels, entirely comprised of office equipment, music, public address systems, and even exterior noise intrusion. The latter environments can also produce noise health effects provided that exposures are long term.
In the case of industrial equipment, the most common techniques for noise protection of workers consist of shock mounting source equipment, creation of acrylic glass or other solid barriers, and provision of ear protection equipment. In certain cases the machinery itself can be re-designed to operate in a manner less prone to produce grating, grinding, frictional or other motions that induce sound emissions.
In the case of more conventional office environments, the techniques in architectural acoustics discussed above may apply. Other solutions may involve researching the quietest models of office equipment, particularly printers and photocopy machines. One source of annoying, if not loud, sound level emissions are certain types of lighting fixtures (notably older fluorescent globes). These fixtures can be retrofitted or analyzed to see whether over-illumination is present, a common office environment issue. If over-illumination is occurring, de-lamping or reduced light bank usage may apply.

[edit] References

1. ^ Benz Kotzen and Colin English, Environmental Noise Barriers: A Guide to Their Visual and Acoustic Design, Spon Press, United Kingdom (1999) ISBN 978-0-419-23180-6 2. ^ Myer Kutz, Handbook of Transportation Engineering,. McGrw-Hill (2004) ISBN 978-0-07-139122-1 3. ^ Aviation Safety and Noise Abatement Act of 1979 (ASNAA), 49 U.S.C. 47501-47510 4. ^ Final Report for the Aircraft Noise Insulation Project for San Francisco International Airport: Phase one Pilot Project, FAA funded and prepared for the city of South San Francisco, Earth Metrics Inc., Burlingame, Calif., July, 1986 5. ^ C.M. Hogan and Ballard George, Pilot Noise Residential Insulation Program, San Jose International Airport (1983) 6. ^ Cyril M. Harris, Noise Control in Buildings: A Practical Guide for Architects and Engineers (1994) 7. ^ Randall F Barron and Barron F Barron, Industrial Noise Control and Acoustics, Marcel Dekker, New York (2002) ISBN 978-0-8247-0701-9

Light pollution

From Wikipedia, the free encyclopedia

Jump to: navigation, search
This article is about light pollution in the visible spectrum. For information on pollution in the radio spectrum, see radio spectrum pollution.
Light pollution, also known as photopollution or luminous pollution, is excess or obtrusive light created by humans. Among other effects, and like any other form of pollution, it disrupts ecosystems, can cause adverse health effects, obscures the stars for city dwellers, and interferes with astronomical observatories. Light pollution can be construed to fall into two main branches: annoying light that intrudes on an otherwise natural or low light setting and excessive light, generally indoors, that leads to worker discomfort and adverse health effects. Since the early 1980s, a global dark-sky movement has emerged, with concerned people campaigning to reduce the amount of light pollution.
Light pollution is a side effect of industrial civilization. Its sources include building exterior and interior lighting, advertising, commercial properties, offices, factories, streetlights, and illuminated sporting venues. It is most severe in highly industrialized, densely populated areas of North America, Europe, and Japan and in major cities in the Middle East and North Africa like Cairo, but even relatively small amounts of light can be noticed and create problems. Like other forms of pollution, such as air, water and noise pollution, light pollution causes damage to the environment.
With recent advances in private spaceflight, the prospect of space-based orbiting billboards appearing in the near future has provoked concern that such objects may become another form of light pollution. With this in mind, the United States Federal Aviation Administration sought permission, in May 2005, to enforce a law prohibiting "obtrusive" advertising in earth orbit.[1][2] Similar intentions are yet to be expressed by authorities in most other countries.

Types of light pollution

[pic]
[pic]
Example of a light pollution source using a broad spectrum metal halide lamp pointing upward. Location: Uniqema Gouda the Netherlands
Light pollution is a broad term that refers to multiple problems, all of which are caused by inefficient, unappealing, or (arguably) unnecessary use of artificial light. Specific categories of light pollution include light trespass, over-illumination, glare, clutter, and sky glow. A single offending light source often falls into more than one of these categories.

[edit] Light trespass

Light trespass occurs when unwanted light enters one's property, for instance, by shining over a neighbor's fence. A common light trespass problem occurs when a strong light enters the window of one's home from outside, causing problems such as sleep deprivation or the blocking of an evening view.
A number of cities in the U.S. have developed standards for outdoor lighting to protect the rights of their citizens against light trespass. To assist them, the International Dark-Sky Association has developed a set of model lighting ordinances.[4] The Dark-Sky Association was started to reduce the light going up into the sky which reduces visibility of stars, see sky glow below. This is any light which is emitted more than 90 degrees above nadir. By limiting light at this 90 degree mark they have also reduced the light output in the 80-90 degree range which creates most of the light trespass issues. U.S. federal agencies may also enforce standards and process complaints within their areas of jursidiction. For instance, in the case of light trespass by white strobe lighting from communication towers in excess of FAA minimum lighting requirements the FCC maintains a database of Antenna Structure Registration information which citizens may use to identify offending structures and provides a mechanism for processing consumer inquiries and complaints. The US Green Building Council (USGBC) has also incorporated into their environmentally friendly building standard known as LEED, a credit for reducing the amount of light trespass and sky glow.
Light trespass can be reduced by selecting light fixtures which limit the amount of light emitted more than 80 degrees above the nadir. The IESNA definitions include full cutoff (10%), cutoff (10%), and semi-cutoff (20%). (These definitions also include limits on light emitted above 90 degrees to reduce sky glow.)
Ordinances have also been written to limit the amount of light at the property line and beyond, but may be unrealistic or vague. Realistic limits and clarity in measurement need to be provided. Stating "zero light at the property line" is too vague. Absolute zero means that even if a light fixture is a mile away and the light source is visible, it is in violation, and would require hoods to be placed over every light fixture. What is realistic may vary according to whether an area is residential or industrial, urban, suburban or rural. The credit offered by LEED provides limits at the property line and 10-15 feet beyond it. At the 10-15 foot distance LEED limits light to 0.01 fc. (For comparison, a full moon provides 0.03 fc and a moonless night 0.004 fc). This is a very difficult limit to comply with while providing even light on a parking lot and driveway. How is the light to be measured? Horizontal measurements are common for interior and exterior lighting calculations. However, for light trespass the concern is how much light shines into a person's eye. Measurements may be made at approximate eye level (5' high) of the vertical light level facing into the site, or aimed at the brightest light source. Exceptions might be allowed where drives enter the street. This would permit street lights at the drive entrance to make cars more visible as they pull into traffic. Limiting pole height is another common ordinance tactic to reduce light trespass. This becomes counterproductive when the ordinance also has max:min ratios for safety concerns. Reducing pole height will increase dark spots on a site. Increasing the number of poles is only viable to a certain point due to the width of the aisles & parking. Otherwise poles would need to be placed in the parking spaces and aisles to maintain even lighting.

[edit] Over-illumination

Main article: Over-illumination
[pic]
[pic]
Office building illuminated by high pressure sodium (HPS) lamps shining upward, of which much light goes into the sky and neighboring apartment blocks and causes light pollution. Location: Nijmegen, the Netherlands
[pic]
[pic]
Composite satellite image of the Earth at night.
Over-illumination is the excessive use of light. Specifically within the United States, over-illumination is responsible for approximately two million barrels of oil per day in energy wasted. This is based upon U.S. consumption of equivalent of 50 million barrels per day (7,900,000 m³/d) of petroleum.[5] It is further noted in the same U.S. Department of Energy source that over 30 percent of all energy is consumed by commercial, industrial and residential sectors. Energy audits of existing buildings demonstrate that the lighting component of residential, commercial and industrial uses consumes about 20 to 40 percent of those land uses, variable with region and land use. (Residential use lighting consumes only 10 to 30 percent of the energy bill while commercial buildings major use is lighting.[6]) Thus lighting energy accounts for about four or five million barrels of oil (equivalent) per day. Again energy audit data demonstrates that about 30 to 60 percent of energy consumed in lighting is unneeded or gratuitous.[7]
An alternative calculation starts with the fact that commercial building lighting consumes in excess of 81.68 terawatts (1999 data) of electricity,[8] according to the U.S. DOE. Thus commercial lighting alone consumes about four to five million barrels per day (equivalent) of petroleum, in line with the alternate rationale above to estimate U.S. lighting energy consumption.
Over-illumination stems from several factors: • Not using timers, occupancy sensors or other controls to extinguish lighting when not needed • Improper design, especially of workplace spaces, by specifying higher levels of light than needed for a given task • Incorrect choice of fixtures or light bulbs, which do not direct light into areas as needed • Improper selection of hardware to utilize more energy than needed to accomplish the lighting task • Incomplete training of building managers and occupants to use lighting systems efficiently • Inadequate lighting maintenance resulting in increased stray light and energy costs • "Daylight lighting" can be required by citizens to reduce crime or by shop owners to attract customers, so over-ilumination can be a design choice, not a fault. In both cases target achievment is questionable. • Substitution of old mercury lamps with more efficient sodium or metal halide lamps using the same electrical power • Indirect lighting tecniques, such as lighting a vertical wall to bouce photons on the ground.
Most of these issues can be readily corrected with available, inexpensive technology; however, there is considerable inertia in the field of lighting design and with landlord/tenant practices that create barriers to rapid correction of these matters. Most importantly public awareness would need to improve for industrialized countries to realize the large payoff in reducing over-illumination

[edit] Glare

Glare is often the result of excessive contrast between bright and dark areas in the field of view. For example, glare can be associated with directly viewing the filament of an unshielded or badly shielded light. Light shining into the eyes of pedestrians and drivers can obscure night vision for up to an hour after exposure. Caused by high contrast between light and dark areas, glare can also make it difficult for the human eye to adjust to the differences in brightness. Glare is particularly an issue in road safety, as bright and/or badly shielded lights around roads may partially blind drivers or pedestrians unexpectedly, and contribute to accidents.
Glare can also result in reduced contrast, due to light scattering in the eye by excessive brightness, or to reflection of light from dark areas in the field of vision, with luminance similar to the background luminance. This kind of glare is a particular instance of disability glare, called veiling glare.
Glare can be categorized into different types. One such classification is described in a book by Bob Mizon, coordinator for the British Astronomical Association's Campaign for Dark Skies.[9] According to this classification: • Blinding Glare describes effects such as that caused by staring into the Sun. It is completely blinding and leaves temporary or permanent vision deficiencies. • Disability Glare describes effects such as being blinded by an oncoming cars lights, or light scattering in fog or in the eye reduces contrast, as well as reflections from print and other dark areas that render them bright, with significant reduction in sight capabilities. • Discomfort Glare does not typically cause a dangerous situation in itself, and is annoying and irritating at best. It can potentially cause fatigue if experienced over extended periods.

[edit] Clutter

Clutter refers to excessive groupings of lights. Groupings of lights may generate confusion, distract from obstacles (including those that they may be intended to illuminate), and potentially cause accidents. Clutter is particularly noticeable on roads where the street lights are badly designed, or where brightly lit advertising surrounds the roadways. Depending on the motives of the person or organization who installed the lights, their placement and design may even be intended to distract drivers, and can contribute to accidents. Clutter may also present a hazard in the aviation environment if aviation safety lighting must compete for pilot attention with non-relevant lighting.[10] For instance, runway lighting may be confused with an array of suburban commercial lighting and aircraft collision avoidance lights may be confused with ground lights.

[edit] Sky glow

[pic]
[pic]
Mexico City at night, with a brightly illuminated sky. Main article: Sky glow
Sky glow refers to the "glow" effect that can be seen over populated areas. It is the combination of all light reflected from what it has illuminated escaping up into the sky and from all of the badly directed light in that area that also escapes into the sky, being scattered (redirected) by the atmosphere back toward the ground. This scattering is very strongly related to the wavelength of the light when the air is very clear (with very little aerosols). Rayleigh scattering dominates in such clear air, making the sky appear blue in the daytime. When there is significant aerosol (typical of most modern polluted conditions), the scattered light has less dependence on wavelength, making a whiter daytime sky. Because of this Rayleigh effect, and because of the eye's increased sensitivity to white or blue-rich light sources when adapted to very low light levels (see Purkinje effect), white or blue-rich light contributes significantly more to sky-glow than an equal amount of yellow light. Sky glow is of particular irritation to astronomers, because it reduces contrast in the night sky to the extent where it may even become impossible to see any but the brightest stars.
The Bortle Dark-Sky Scale, originally published in Sky & Telescope magazine,[11] is sometimes used to quantify sky glow and general sky clarity. The Bortle Scale rates the darkness of the sky and the visibility of night sky phenomena such as the gegenschein and the zodiacal band, easily masked by sky glow, on a scale of one to nine, providing a detailed description of each step on the scale.
Light is particularly problematic for amateur astronomers, whose ability to observe the night sky from their property is likely to be inhibited by any stray light from nearby. Most major optical astronomical observatories are surrounded by zones of strictly-enforced restrictions on light emissions.
"Direct" sky glow can be reduced by selecting lighting fixtures which limit the amount of light emitted more than 90 degrees above the nadir. The IESNA definitions include full cutoff (0%), cutoff (2.5%), and semi-cutoff (5%). "Indirect" skyglow produced by reflections from vertical and horizontal surfaces is harder to manage; the only effective method for preventing it is by minimizing over-illumination.

[edit] Measurement of light pollution and global effects

[pic]
[pic]
False colors show various intensities of radiation — both direct and indirect — from artificial light sources that reach space (Image credit: P. Cinzano)
Measuring the effect of sky glow on a global scale is a complex procedure. The natural atmosphere is not completely dark, even in the absence of terrestrial sources of light. This is caused by two main sources: airglow and scattered light.
At high altitudes, primarily above the mesosphere, UV radiation from the sun is so intense that ionization occurs. When these ions collide with electrically neutral particles they recombine and emit photons in the process, causing airglow. The degree of ionization is sufficiently large to allow a constant emission of radiation even during the night when the upper atmosphere is in the earth's shadow.
Apart from emitting light, the sky also scatters incoming light, primarily from distant stars and the Milky Way, but also sunlight that is reflected and backscattered from interplanetary dust particles (the so-called Zodiacal light).
The amount of airglow and zodiacal light is quite variable but given optimal conditions the darkest possible sky has a brightness of about 22 magnitude/square arcsecond. If a full moon is present, the sky brightness increases to 18 magnitude/sq. arcsecond, 40 times brighter than the darkest sky. In densely populated areas a sky brightness of 17 magnitude/sq. arcsecond is not uncommon, or as much as 100 times brighter than is natural.
To precisely measure how bright the sky gets, night time satellite imagery of the earth is used as raw input for the number and intensity of light sources. These are put into a physical model[12] of scattering due to air molecules and aerosoles to calculate cumulative sky brightness. Maps that show the enhanced sky brightness have been prepared for the entire world.[13]
Inspection of the area surrounding Madrid reveals that the effects of light pollution caused by a single large conglomeration can be felt up to 100 km away from the center. Global effects of light pollution are also made obvious. The entire area consisting of southern England, Netherlands, Belgium, west Germany, and northern France have a sky brightness of at least 2 to 4 times above normal (see above right). The only place in continental Europe where the sky can attain its natural darkness is in northern Scandinavia.
In North America the situation is comparable. From the east coast to west Texas up to the Canadian border there is very significant global light pollution.

[edit] Consequences of light pollution

[edit] Energy waste

Lighting is responsible for one-fourth of all energy consumption worldwide,[citation needed] and case studies have shown that several forms of over-illumination constitute energy wastage, including non-beneficial upward direction of night-time lighting. Piedmont, a northern region of Italy, allows 1/10 of lighting upwards in each municipality.[clarify] On a national basis the savings are estimated at about 80 billion Euros and about 600 GWh, according to an October 2007 press release by Terna.[citation needed]

[edit] Effects on human health and psychology

Medical research on the effects of excessive light on the human body suggests that a variety of adverse health effects may be caused by light pollution or excessive light exposure, and some lighting design textbooks[14] use human health as an explicit criterion for proper interior lighting. Health effects of over-illumination or improper spectral composition of light may include: increased headache incidence, worker fatigue, medically defined stress, decrease in sexual function and increase in anxiety.[15][16][17][18]
Common levels of fluorescent lighting in offices are sufficient to elevate blood pressure by about eight points. There is some evidence that lengthy daily exposure to moderately high lighting leads to diminished sexual performance.[citation needed] Specifically within the USA, there is evidence that levels of light in most office environments lead to increased stress as well as increased worker errors.[19][20] However, such high interior lighting levels are not typical outside North America.
Several published studies also suggest a link between exposure to light at night and risk of breast cancer, due to suppression of the normal nocturnal production of melatonin.[21][22]
In 1978 Cohen et al proposed that reduced production of the hormone melatonin might increase the risk of breast cancer and citing "environmental lighting" as a possible causal factor.[23]
Researchers at the National Cancer Institute (NCI) and National Institute of Environmental Health Sciences have concluded a study that suggests that artificial light during the night can be a factor for breast cancer.[24]
In 2007, "shiftwork that involves circadian disruption" was listed as a probable carcinogen by the World Health Organization's International Agency for Research on Cancer. (IARC Press release No. 180).[25] Multiple studies have documented a link between night shift work and the increased incidence of breast cancer.[26][27][28][29]
A good review of current knowledge of the health consequences of exposure to artificial light at night and an explanation of the causal mechanisms has been published in the Journal of Pineal Research in 2007.[30]

[edit] Disruption of ecosystems

Life exists with natural patterns of light and dark, so disruption of those patterns influences many aspects of animal behavior.[31] Light pollution can confuse animal navigation, alter competitive interactions, change predator-prey relations, and influence animal physiology.
Studies suggest that light pollution around lakes prevents zooplankton, such as Daphnia, from eating surface algae, helping cause algal blooms that can kill off the lakes' plants and lower water quality.[32] Light pollution may also affect ecosystems in other ways. For example, Lepidopterists and entomologists have documented that night-time light may interfere with the ability of moths and other nocturnal insects to navigate.[33] Night blooming flowers that depend on moths for pollination may be affected by night lighting, as there is no replacement pollinator that would not be affected by the artificial light. This can lead to species decline of plants that are unable to reproduce, and change an area's longterm ecology.
Migrating birds can be disoriented by lights on tall structures. Estimates by the U.S. Fish and Wildlife Service of the number of birds killed after being attracted to tall towers range from 4-5 million per year to an order of magnitude higher.[34] The Fatal Light Awareness Program (FLAP) works with building owners in Toronto, Canada and other cities to reduce mortality of birds by turning out lights during migration periods.
Other well-known casualties of light pollution are sea turtle hatchlings emerging from nests on beaches. It is a common misconception that hatchling sea turtles are attracted to the moon. They are not; rather, they find the ocean by moving away from the dark silhouette of dunes and their vegetation, a behavior with which artificial lights interfere.[35] Juvenile seabirds may also be disoriented by lights as they leave their nests and fly out to sea.
Nocturnal frogs and salamanders are also affected by light pollution. Since they are nocturnal, they wake up when there is no light. Light pollution may cause salamanders to emerge from concealment later, giving them less time to mate and reproduce.
A book that assembles various research on the subject was released in 2005.[36]

[edit] Loss of safety

It is generally agreed that many people require light to feel safe at night, but campaigners for the reduction of light pollution often claim that badly or inappropriately installed lighting can lead to a reduction in safety if measured objectively, and that at the very least, it is wrong to assume that simply increasing light at night will lead to improved safety.
The International Dark-Sky Association claims there are no good scientific studies that convincingly show a relationship between lighting and crime. Furthermore, the association claims that badly installed artificial lights can create a deeper contrast of shadows in which criminals might hide.[37] The New England Light Pollution Advisory Group claims that some light emitted by some fixtures can be a significant hazard to motorists, pedestrians, and bicyclists due to their scattering of light and glare.[38]
The specific effects of outdoor lighting on safety are still a topic of debate, and formal research in the area is not well established.

[edit] Effect on astronomy

|[pic] |Please help improve this section by expanding it. Further information might be found on the talk page or at requests for |
| |expansion. (August 2007) |

Skyglow reduces the contrast between stars and galaxies in the sky and the sky itself, making it more difficult to detect fainter objects. This is one factor that has caused newer telescopes to be built in increasingly remote areas. Some astronomers use narrow-band "nebula filters" which only allow specific wavelengths of light commonly seen in nebulae, or broad-band "light pollution filters" which are designed to reduce (but not eliminate) the effects of light pollution by filtering out spectral lines commonly emitted by sodium- and mercury-vapor lamps, thus enhancing contrast and improving the view of dim objects such as galaxies and nebulae. Unfortunately this affects color perception, so these filters cannot be used to visually estimate variable star brightness, and no filter can match the effectiveness of a dark sky for visual or photographic purposes. Due to low surface brightness, the visibility of diffuse sky objects such as nebulae and galaxies is affected by light pollution more than are stars. A simple method for estimating the darkness of a location is to look for the Milky Way.
Light trespass can impact observations when stray light enters the tube of the telescope from off-axis, and is reflected from surfaces other than the telescope's mirrors (if any) so that it eventually reaches the eyepiece, causing a glow across the field of view since it has not been focused. The usual measures to reduce this glare, if reducing the light directly (e.g. by changing one's location or having the light turned off) is not an option, include flocking the telescope tube and accessories to reduce reflection, and putting a light shield (also usable as a dew shield) on the telescope to reduce light entering from angles other than those near the target. In one Italian regional lighting code this effect of stray light is defined as "optical pollution", due to the fact that there is a direct path from the light source to the "optic" - the observer's eye or telescope.

[edit] Reducing light pollution

Reducing light pollution implies many things, such as reducing sky glow, reducing glare, reducing light trespass, and reducing clutter. The method for best reducing light pollution, therefore, depends on exactly what the problem is in any given instance. Possible solutions include: • Utilizing light sources of minimum intensity necessary to accomplish the light's purpose. • Turning lights off using a timer or occupancy sensor or manually when not needed. • Improving lighting fixtures, so that they direct their light more accurately towards where it is needed, and with less side effects. • Adjusting the type of lights used, so that the light waves emitted are those that are less likely to cause severe light pollution problems. • Evaluating existing lighting plans, and re-designing some or all of the plans depending on whether existing light is actually needed.

[edit] Improving lighting fixtures

[pic]
[pic]
A flat-lens cobra luminaire, which is a full-cutoff fixture, may be effective in reducing light pollution. It ensures that light is only directed below the horizontal, which means less light is wasted through directing it outwards and upwards.
[pic]
[pic]
This drop-lens cobra luminaire allows light to escape sideways and upwards, where it may cause problems.
The use of full cutoff lighting fixtures, as much as possible, is advocated by most campaigners for the reduction of light pollution. It is also commonly recommended that lights be spaced appropriately for maximum efficiency, and that lamps within the fixtures not be overpowered.
A full cutoff fixture, when correctly installed, reduces the chance for light to escape above the plane of the horizontal. Light released above the horizontal may sometimes be lighting an intended target, but often serves no purpose. When it enters into the atmosphere, light contributes to sky glow. Some governments and organizations are now considering, or have already implemented, full cutoff fixtures in street lamps and stadium lighting.
The use of full cutoff fixtures may help to reduce sky glow by preventing light from escaping unnecessarily. Full cutoff typically reduces the visibility of the lamp and reflector within a luminarie, so the effects of glare may also be reduced. Campaigners also commonly argue that full cutoff fixtures are more efficient than other fixtures, since light that would otherwise have escaped into the atmosphere may instead be directed towards the ground. However, full cutoff fixtures may also trap more light in the fixture than other types of luminaires, corresponding to lower luminaire efficiency.
The use of full cutoff fixtures may allow for lower wattage lamps to be used in the fixtures, producing the same or sometimes a better effect, due to being more carefully controlled. In every lighting system, some sky glow also results from light reflected from the ground. This reflection can be reduced, however, by being careful to use only the lowest wattage necessary for the lamp, and setting spacing between lights appropriately.[39]
A common criticism of full cutoff lighting fixtures is that they are sometimes not as aesthetically pleasing to look at. This is most likely because historically there has not been a large market specifically for full cutoff fixtures, and because people typically like to see the source of illumination. Due to the specificity with their direction of light, full cutoff fixtures sometimes also require expertise to install for maximum effect.
The effectiveness of using full cutoff roadway lights to combat light pollution has also been called into question. According to computer simulations, luminaires with full cutoff distributions (as opposed to cutoff or semi cutoff, compared here) have to be closer together to meet the same light level, uniformity and glare requirements specified by the IESNA.[40][41][42][43] These simulations attempted to optimize the height and spacing of the lights while constraining the overall design to within the IESNA requirements, and then compared total uplight and energy consumption of different luminaire designs and powers. Cutoff designs paradoxically performed better than full cutoff designs. This indicates that, in roadway installations, over-illumination required by full cutoff fixtures may be more detrimental than direct uplight created by fewer cutoff fixtures. Therefore, existing systems could be improved more by reducing the number of luminaires than by switching to full cutoff designs.

Adjusting types of light sources

Several different types of light sources exist, each having different properties that affect their appropriateness for certain tasks, particularly efficiency and spectral power distribution. It is often the case that inappropriate light sources have been selected for a task, either due to ignorance or because more sophisticated light sources were unavailable at the time of installation. Therefore, badly chosen light sources often contribute unnecessarily to light pollution and energy waste. By re-assessing and changing the light sources used, it is often possible to reduce energy use and pollutive effects while simultaneously greatly improving efficiency and visibility.
Some types of light sources, in order of energy efficiency, are:

|Type of light source |Color |Luminous Efficacy |
| | |(lumens per watt) |
|Low Pressure Sodium (LPS/SOX) |yellow/amber |80 - 200 |
|High Pressure Sodium (HPS/SON) |pink/amber-white |90 - 130 |
|Metal Halide |bluish-white/white |60 -120 |
|Mercury-Vapour |blue-greenish white |13 - 48 |
|Incandescent |yellow/white |8 - 25 |

Noise Pollution: A Modern Plague

Lisa Goines, RN; Louis Hagler, MD Southern Medical Journal 2007;100(3):287-294. ©2007 Lippincott Williams & Wilkins

Abstract and Introduction

Abstract

Noise is defined as unwanted sound. Environmental noise consists of all the unwanted sounds in our communities except that which originates in the workplace. Environmental noise pollution, a form of air pollution, is a threat to health and well-being. It is more severe and widespread than ever before, and it will continue to increase in magnitude and severity because of population growth, urbanization, and the associated growth in the use of increasingly powerful, varied, and highly mobile sources of noise. It will also continue to grow because of sustained growth in highway, rail, and air traffic, which remain major sources of environmental noise. The potential health effects of noise pollution are numerous, pervasive, persistent, and medically and socially significant. Noise produces direct and cumulative adverse effects that impair health and that degrade residential, social, working, and learning environments with corresponding real (economic) and intangible (well-being) losses. It interferes with sleep, concentration, communication, and recreation. The aim of enlightened governmental controls should be to protect citizens from the adverse effects of airborne pollution, including those produced by noise. People have the right to choose the nature of their acoustical environment; it should not be imposed by others.

Noise Pollution: A Modern Plague

... in duration (4 h) and frequency (four times/yr).[1] The threshold for pain is ... This form of noise is underestimated with the usual types of sound ... wind-watch.org/documents/.../uploads/goineshagler-noisepollution.html – dd9-9-2008-09-09

Noise pollution - Wikipedia, the free encyclopedia

Other types of pollution ... 4 Mitigation and control of noise. 5 Legal status ... equipment, shock mounting assemblies and physical barriers in the workplace. ... en.wikipedia.org/wiki/Noise_pollution - Cached

noise pollution: Definition from Answers.com

Other types of pollution ... moderately high levels of environmental noise.[4] ... equipment, shock mounting assemblies and physical barriers in the workplace. ... www.answers.com/topic/noise-pollution - 91k - Cached

Noise Pollution: A Modern Plague

... in duration (4 hours) and frequency (four times/year).1 The threshold for pain ... This form of noise is underestimated with the usual types of sound ... www.nonoise.org/library/smj/smj.htm - 91k - Cached
9.9.2008