TA: Ph. Danna
Date: Dec. 10.2014
In 1926 Edmund Germer came very close to developing the modern fluorescent lamp, but because of its ugly green color, it didn’t get any investors attention. Later, we concern the one which has real white phosphors, is stable, reliable, and the design has not changed much in 78 years is the first true fluorescent lamp by Richard Thayer, Eugene Lemmers, and Willard A. Roberts in 1934 (The Fluorescent Lamp- How It Works & History). Today fluorescent lighting sources are a large family of lighting sources which are incandescent, fluorescent, high-intensity discharge, and LED. It is the most common type of electrical light used in the United States. It is estimated that there are 1.5 billion fluorescent lamps in use nationwide, mostly in commercial setting such offices, factories, stores, and schools (Wyatt, Edward). Because of the advantage of raw materials glass, mercury, and phosphor low production cost, high luminous efficacy and various design however, fluorescent lighting sources become the most popular today; however, in a long-term whole life cycle of fluorescent lighting, these raw materials still exist some potential harms to the environment and human health.
The tube of fluorescent lamp is made of glass which takes the most part of quantity, but less cost because the raw material is cheap. The glass tube used in a compact fluorescent lamp is made from soda-lime glass which is most widely used glass for windows, bottles, light bulbs, and jars. Silica sand is the source for soda-lime which relatively close to the land surface ( roughly within 50ft). It is composed of grains that are nearly all quartz, typically greater than 95 percent, and is much rarer on the surface of the earth today. It is different from most sand which at the earth surface today is composed of grains of a number of different minerals. The reason why the glass is cheap is because the large volume in global world with large demand, consumption. For example, according to the statistic from the article World Industrial Silica Sand Market by PRN news, the global demand for silica sand is forecast to climb 4.4 percent annually through 2016 to 278 million metric tones. The large demand of silica sand is the consumption of glass market which is accounting for 37 percent of global silica sand consumption in 2011. Fortunately, we have the large volume of silica sand in global to remain the glass price cheap. Current world production of glass is estimated at 140-150 Mt per year. 56% of silica sand demand between 2011 and 2016 will share from the Asia/Pacific region, particularly in China and India. China will continue present the largest national market for industrial sand, accounting for 34 percent of all global demand in volume terms in 2016. According to my research the raw material of silica sand from Alibaba, the majority of suppliers can supply 5000 tons per month, and the price can be from 10 USD to 300 USD per ton which is FOB price and depends on the quantity of order (“World Industrial Silica Sand Market”).
Beyond that the feature of glass also allows to create various designs of fluorescent lightings. To understand the features of glass, we have to understand the characters with lower melting point and higher coefficient or expansion and contraction in the forming process. This is an important factor to consider different size, shape and color of the tube. Soda-lime glass is prepared by melting the raw material such as soda, lime, silica, alumina, and small quantities of fining agents in a glass furnace at temperatures locally up to 1675C. There are 3 import points. The first one is softening point. Soda-lime glass’ soften point is 726 C ( 1340 F). At this temperature glass will begin to sag. If the temperature is reduced slightly, the glass will remain in the sagged shaped. The second one is Annealing point which is 546 C (1015 F) for soda-lime glass. At this temperature glass will relieve stresses ( either compressive or tensile) in a matter of minutes. This is also the temperature in order to prevent “ cold-cracking” during quench. The third one is strain point which is 514 C ( 957 F) for soda-lime glass (“ The Fluorescent Lamp- How It Works & History”). At this temperature glass will relieve stresses over a period of hours. In short, soda-lime glass can be chemically tempered to increase mechanical strength, be heated strengthened or heat tempered to increase thermal shock resistance and mechanical strength, be bent laminated, machined, optically coated, chemically etched, sandblasted or colored. As the properties of soda-lime glass, fluorescent lamps have various designs of shape and size. The most common form of fluorescent lamp is a straight tube. The size range is from T2 to T17. Circles fluorescent lamps in the form of circles are called Circline lamps. Those with a T9 tube diameter are available with outside diameters of 6/2’’, 8’’ 12’’, or 16’’.
Mercury is an essential small amount in the fluorescent lighting as we see in the market, but we cannot ignore its harm to the environment in its life cycle. Mercury has been found in Egyptian tombs and used for cosmetic and medicinal purpose 1500 BC or even earlier. It is a naturally occurring element found in rocks, soil, water, air and living things. Mercury is the only metal that is liquid at room temperature. In its pure form (often called metallic or elemental), mercury is a shiny, silver-white, odorless liquid. Mercury is needed to make the inert gasses conductive at all temperatures and to make the lamp work properly and efficiently. When we turn on electricity, the arch which started in argon gas quickly warms up the mercury liquid stuck to the side of tube. The mercury boils or vaporizes into the arch stream. This creates UV light. However, like many heavy metals, mercury can be hazardous to the environment. If a CFL breaks, it can release some of its mercury although this is usually part of a solid constituent of the lamp at normal temperatures. Releasing mercury can be in our air, water, and land will cause environment pollution and human health problem.
Moreover according to the U.S Environmental Protection Agency, people in the U.S are mainly exposed to mercury, an organic compound, when they eat fish and shellfish that contain mercury. It will adversely affect a fetus’ growing brain and nervous system. Impacts on cognitive thinking, memory, attention, language, and fine motor and visual spatial kills have been seen in children exposed to mercury in the womb. Moreover, elemental mercury primarily causes health effects when it is breathed as a vapor where it can be absorbed through the lungs. Also the article, from Christian Science Monitor points out that most of the mercury that deep sea ocean fish are loaded with more mercury than are their counterparts in shallower waters. The difference in mercury levels in shallow and deep-water fish as the amount of sunlight to which the amount of sunlight to which the animals are exposed and proposes that most of the mercury that humans consume is produced in the deep ocean (Barber, Elizabeth). These expose mercury to the air, particularly in warm or poorly-ventilated indoor space. Symptoms include these: tremors; emotional changes, such as mood swings, irritability, nervousness, excessive shyness; insomnia; neuromuscular changes as weakness, muscle atrophy, twitching; headaches; disturbances in sensations; changes in nerve responses; performance deficits on tests of cognitive function. At higher exposures there may be kidney effects, respiratory failure and death. People concerned about their exposure to elemental mercury should consult their physician. The amount of mercury depends on the type of fluorescent lamp. They can contain a wide range of mercury, from greater than 0 up to 100 milligrams. According to the National Electrical Manufacturers Association (NEMA), about half of the fluorescent lamps manufactured by their members and sold in the U.S contain 5 to 10 mg of mercury. So, if a fluorescent tube breaks, the first thing to do is not to touch the mercury powder, but pick up the shattered glass, preferably with something to avoid direct contact, then wipe the heavy metal with a wet cloth and put it in a sealed container. Brooms and vacuums should be avoided at all the time, since they spread the mercury even more.
Phosphor is a substance displays the property of luminescence which provides various colors and light intensity for different marketing and decorative purpose. It is known for its use in radar screens and glow-in-the dark toys, whereas fluorescent materials are common in CRT screens, sensors, and white LEDs. In addition to primary colors, several shades of “White” are marketed by the fluorescent lamp manufacturers for general lighting use. These tend to fall into three shades: Warm white, Cool White and Daylight. The ratio of the phosphors used determines whether the produced light is perceived as Warm White, Cool White, or Daylight shades. The Warm White lamps have more red and orange light, and are marketed towards use in residential. The Cool White lamps are the “normal” fluorescent lamp color, with more green in the produced light. This is the most commonly-used lamp color by far for traditional fluorescent lamps. Compact Fluorescent Lamps are still targeted at the home. Daylight lamps have a blue tint and are supposed to mimic the color of light reflected from a clear sky. These tend to have a “cold” appearance. Furthermore, lamps that produce, red, green, blue and other colors are available. Green and blue lamps appear normal until illuminated. For other case of red and some of the other colors, a phosphor that produces a bright light is chosen and then the glass is tinted to the desired color. In recent years, some manufacturers have added a new specification to their near-white lamps, called the Color Rendition Index, or CRI. The higher the number, the better the light quality is supposed to be. In general, this means that the phosphors selected generate frequencies of light closer to what the cones in the human eye can most readily detect. Beside them, we need to understand the number of lumens, angstroms or nanometers, and Kelvin. Lumens measure how much light you are getting from a bulb. More lumens means it’s brighter light; fewer lumens means it’s a dimmer light. Astronomers use a tiny unit of distance called the “angstrom” to measure wavelengths. The “visible lights” corresponds to a wavelength range of 400-700 nm and a color range of violet through red. Human eyes are not capable of seeing radiation with wavelength outside of visible spectrum. Kelvin is measured for color temperature. Over 5000k are called cool colors, while lower color temperature are called warm colors (2700-3000k).
Starting Jan. 1, the United States will no longer manufacture or import incandescent bulbs, although stores can still sell what they have in stock. An incandescent bulb can cost as little as 70 cents. Meanwhile, a CFL bulb sells for at least a few dollars and an LED starts at 10. The main reason Fluorescent lamps won the market because of its energy-efficient than incandescent bulbs, and its low cost than LED. At the same time we should never ignore the harms of mercury using in CFL lamps. Recycling is the most important responsibility to keep our environment clean and having a healthy life style. And I believe the future of fluorescent lighting will be replaced by using mercury because today science have developed a revolutionary lighting technology that the common incandescent light bulb and does not contain mercury, making it environmentally safer than the compact fluorescent light (CFL)bulb.
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December 11, 2014
Waste and Emission of Fluorescent Lights
From hand held torches, to incandescent, to fluorescent lights, and LED or Light Emitting Diode; lights became more efficient as its lifespan increases and reduces the use of hazardous materials. With the mass production of LED, fluorescent light bulbs swiftly makes its way to either be recycled or into the landfill. Fluorescent light bulbs have a lifespan of 6,000 hours and by the end of their life, the “electricity use will have led to 462 kg of mercury emissions (from coal fired power plants)” (Greenfacts.org). If only 20% of fluorescent light bulbs are recycled, “an estimated 1130 kg of mercury would eventually be released by inappropriate disposal" (Greenfacts.org). In a report by Household Universal Waste Generation in California, August 2002, “there were 15,555,556 fluorescent lamps sold in California in the year 2001” and “only 0.21% of these lamps were recycled”(calrecycle.ca.gov). Meaning that at least 0.79% of the fluorescent light bulbs made its way into landfill or collecting dust and having a greater possibility of breaking inside homes. In the process of manufacturing fluorescent light bulbs, the materials used are all recyclable and reusable; such as glass, phosphor coating, and mercury. As more people invest in LED lights, which does not use any mercury, the improper disposal of fluorescent light bulbs accumulates into landfill releasing an amount of harmful mercury into the environment.
Glass tubes are the first component in making fluorescent light bulbs and those that does not reach requirements are recycled, burned, and reused at the manufacturer. Glass can be recycled infinite of times keeping its strength and functionality. During the process of melting raw materials to produce glass; carbon dioxide, sulfur dioxides, and nitrogen oxides are released into the air. Glass are made by melting silica, soda ash, and limestone together at a high temperature of 1700 Celsius. This is the start of the waste and emission in the production of fluorescent lights. The environmental impact of glass production are caused by melting these activities:
● “The combustion of natural gas/fuel oil and the decomposition of raw materials during the melting lead to the emission of CO2. This is the only greenhouse gas emitted during the production of glass.
● Sulphur dioxide (SO2) from the fuel and/or from decomposition of sulphate in the batch materials can contribute to acidification and formation of SMOG.
● Nitrogen oxides (NOx) due to the high melting temperatures and in some cases due to decomposition of nitrogen compounds in the batch materials also contribute to acidification.
● Evaporation from the molten glass and raw materials can cause release of particles in the atmosphere” (agc-glass.eu).
The glass tube is an important component to have since it is inside the tube that the excited argon and mercury react to produce light. It holds all the hazardous materials inside. When reusing crushed and recycled glass known as cullet, we avoid wasting materials of used glass and reduces the need for more raw materials into manufacturing the glass. Magnet, suction, and laser sorter are used to remove contamination and non-glass materials. Using cullet replaces carbonates and reduces Carbon Dioxide emission. For every 10% use of cullet, an estimated “2.5-3% in energy savings can be achieved" (britglass.org).
The glass tube then gets coated inside with phosphor that emits visible lights as it is excited by electrons of the mercury and argon gas.” When the UV [a dangerous exposure] rays hit the phosphor [which absorb the UV lights], they fluoresce, or glow [a visible, white light]" (energystar.gov). Phosphor does not have a huge environmental impact however it can cause blood clotting and prevent healing when injured from cut glass that are coated with phosphor. Phosphor in fluorescent light bulb can be separated from mercury and be reuse again. Through my research, there was limited information of phosphor used in fluorescent light bulb since it is not a major environmental impact.
Mercury, a colorless and odorless element, is essential in manufacturing fluorescent lights bulb because “the properties of these mercury atoms make them very efficient light emitters by fluorescence when they are struck by energetic electrons inside the tube" (hyperphysics). Mercury and argon gas is inserted inside the sealed glass tube and when electricity passes the filament of tungsten and contact with the mercury, it gives off lights. Mercury is highly toxic metal and harmful, when a bulb breaks the mercury escapes as vapor and as a fine powder. The vapor mercury can be inhaled while the powder settles on carpet. Mercury contaminates the atmosphere, surface water, and soil. The U.S. Environmental Protection Agency (EPA) reported “that lamps containing mercury contribute 3.8 percent of all mercury entering municipal solid waste (MSW) landfills" (doi.gov). Mercury are poisonous to the nervous system and the kidneys, yet there are not enough evidences to conclude that it causes cancer in human. However, during pregnancy if exposed to methyl mercury it may affect the unborn baby brain. Methyl mercury are health hazard as it is found in food such as fish and other seafood and is easily consumed through the stomach to the intestines. Although mercury that are ingested are not as hazardous as inhaling vapor mercury, inhaled vapor mercury are absorbed “into the body via the lungs and move easily from the bloodstream into the brain” (greenfacts.org). In contributing in contaminating the surface water, mercury are consumed by fishes and caused elevated concentrations in them. In warning of elevated levels of mercury in fish, thirty-four states have issued fish consumption advisories and eight advisories have issued in North Carolina as of November 1994.
Used fluorescent light bulbs are collected and gets recycled in recycling facility/management. All materials are recyclable and are separated by going through a crusher. The crusher separates the glass, metals, and phosphor with mercury. Chemical separation process are used to separate phosphor and mercury. Phosphor powder are reusable, while recovered mercury have to go through triple distillation process to be clean and be reusable.
Transport is a huge contributions to global warming producing more than half of carbon dioxides and nitrogen oxides. After completed processed and testing, fluorescent light bulbs are ready to be shipped to retailers/department stores. Through that, consumer are able to obtain the light bulbs. In the processes of getting the fluorescent light bulbs to the retailer/department stores and to the consumer, carbon dioxides are emitted into the atmosphere “during vehicle operation, refueling, manufacturing, and disposal” (ucsusa.org). With that gas and oil are constantly demanded, and so the pumping of oil are constantly on going. With the production of fluorescent light bulbs, we cannot stop transportation emission even if we change to LED because to get LED lights to the consumer, it also need some kind of transportation. If considering bicycle transportation, there are many downfall. Bicycle are not as efficient, as fast, and would not carry a huge quantity as vehicle. Also to be able to transport to longer distances, bicycle would not be efficient enough to make it to its destination, although it would be environment friendly.
There are very limited ways for us to prevent these hazardous due to the fact that we are living in a generation where technologies are improving at a rapid pace. With the topic of lights, it is always innovated for the better, yet there will always be something harmful or disliked by society about new innovation; therefore increasing the demand of new and better versions. Fluorescent light bulbs’ flaws are the materials it contains, that is the coating of phosphor and the minimal use of mercury, which are harmful to the environment and human’s health through a great amount as it accumulates.
With incandescent banned and LED making its way innovating the lights industry, fluorescent light bulbs are slowly pushed into landfill. Mercury accumulates into the atmosphere impacting in human health systems and taking up more lands as it continue to be improperly disposal. We can help prevent mercury being released into the environment by properly placing it in designated recycled trash. Then used and recycled fluorescent light bulbs are transported to certify recycling firms. From there they are able to be crushed, separated, and burned back into fluorescent light bulbs with minimal waste and emission. All we have to do is play our part in making sure we properly recycled our fluorescent light bulbs.
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