Design Life-Cycle

Mackenzie Payton Foley Phillips

Professor Cogdell 

TA: Amanda

Design 40 A, Winter Quarter

14 March 2016

The Life Cycle of a Snowboard: Materials

    Snowboards were first developed in the Muskegon, Michigan by Sherman Poppen. He named his sled-like invention the snurfer because the design was inspired by surf and skateboard technology. The snurfer was a monoski composed of hand-shaped plywood, which was ridden like a snowboard but did not have bindings [6]. Since Poppen’s invention of the snurfer, snowboard technology has evolved drastically. Burton, the world’s leading company in snowboard design and production improved Poppen’s design with the use of more durable materials like: steel, aluminum, plastic, epoxy and fiberglass. Due to the environmental effects of manufacturing these materials, the lifecycle of a snowboard from cradle to grave has a long-term impact on the earth. Additionally, the extraction of these materials is depleting earth’s finite resources and producing adverse byproducts, which increases global temperatures overtime. 

    The base material of snowboards is made from a polyethylene plastic called p-tex. There are two different types of p-tex: extruded and sintered. Extruded p-tex is “a low molecular weight polyethylene”, which is heated to 350 degrees Fahrenheit and is pressurized and fed through a slot to yield the desired thickness. Sintered p-tex is made from “ultra high molecular weight polyethylene powder”, which is condensed and formed into a large slab of plastic [2]. The desired thickness and shape of the snowboard’s base is then shaved off of the sintered p-tex slab. In the production of high performance snowboards, sintered p-tex is favored over extruded p-tex because sintered has 20-25% more efficiency in reducing friction and impact resistance. Additionally, sintered p-tex has the ability to absorb 3 times more wax, which also helps with the reduction of friction and promotes speed [2]. 

Often times, graphite and carbon are embedded in sintered p-tex to help promote electrical and thermal conductivity. These types of bases are called Electra bases. The implication of Electra bases helps dissipate the “frictional heat” throughout the entire snowboard; this prevents the frictional heat from building up in particular areas of the snowboard [2]. The dissipation of heat and friction is helpful because it allows the board to slide more smoothly across the snow in a variety of conditions. Although the use of p-tex is durable, it is not easy to recycle. In order for the p-tex to be properly recycled, the fused layers of the snowboard would have to be disassembled and sorted. Once the polyethylene is tediously extracted from the snowboard, it could then be melted, reused and repurposed. Aside from the difficult labor coinciding with disassembling a snowboard, the recycled p-tex would become brittle and less durable each time it is recycled [2].  Additionally, in order to extract the graphite used in p-tex, it must be mined from earth’s surface, which causes physical and environmental destruction.

Graphite is also used in snowboard wax as another way to reduce heat and friction. Although only small amounts of graphite are used in the production of snowboards and snowboard wax, the use of this material has detrimental impacts on the earth [12]. The extraction of graphite is completed through underground and open pit mining techniques. During the processes of open pit mining large equipment like bulldozers, dump trucks, and scrapers are used to deface the earth’s surface. These machines are powered by combustion engines that contribute to the emission of greenhouse gasses, leading to depletion of the ozone layer. 

The core of a snowboard is traditionally made of hand carved wood, which is usually then layered between epoxy resin and fiberglass in a heated press. The use of wood in the manufacturing of snowboards contributes to deforestation. Burton created an aluminum honeycomb core an alternative to wooden cores. The benefit to using aluminum instead of wood is that aluminum can be recycled and repurposed. However, due to the fact that the materials are heated and compressed in machine, extracting the aluminum becomes a very challenging and time-consuming task. This is why there are not many recycling programs in effect for snowboards. Although aluminum seems like a better alternative to using wood, extracting aluminum is an energy intensive process. 

Bauxite is the raw, organic ore which aluminum is made from. The extraction of bauxite and its conversion into aluminum requires “copious amounts of electricity, water and resources” [11]. Similar to graphite, bauxite is mined from earth’s surface by the open-pit mining method. As mentioned before, this mining method destroys earth’s vegetation and biodiversity, while emitting greenhouse gasses. Open pit mining also causes acid mine drainage, which severely damages the soil and earth’s underground water tables. Once bauxite is removed from the earth it is heavily processed and smelted, with the use of coal. Coal burns dirtily, emitting hazardous pollutants, acidic gasses and particulate matter into the air. When aluminum is smelted it releases perfluorocarbons, which are “9,200 times more harmful than carbon dioxide in terms of their affect on global warming” [11]. Greenhouse gasses and particulate matter are also released into the atmosphere, which compromises air quality; thus leading to respiratory disease. 

Epoxy and fiberglass are also important components of a snowboard, giving the board shape and keeping the materials together. Epoxy resin is an extremely strong adhesive, which is made with a chemical reaction of polyhydric phenols and aqueous inorganic hydroxide [8]. Creating epoxy is a complicated and particular process involving the elimination of salts and extraction of water. Although, the production of epoxy is complicated, the biggest challenge with making epoxy is finding a cost effective way to manufacture it. Fiberglass is important because it gives the board its shape. The production of glass for fiberglass is an energy intensive process, which is highly dependent on fossil fuels. There are more natural alternatives to the utilization of fiberglass. The production of natural fibers derived from plants would require 5-10 times less energy than that of glass fibers [1]. The incorporation of natural fibers in snowboard design would save energy and reduce hazardous emissions from fossil fuels. 

The top sheet of the snowboard is made from polybutylene terephthalate, also known as PBT. PBT is an insulating plastic that is also used in electronics due to its thermoplastic, or heat resistant properties. Polybutylene terephthalate performs well under high impact and varying temperatures, which makes it a good material for a snowboard. Similar to other plastics, PBT is made from oil, which also happens to be a fossil fuel and a non-renewable resource [9]. 

Steel is one of the most important materials in a snowboard because it is what makes the edges sharp, allowing the board to grip the snow. The strength and durability are two beneficial qualities that steel possesses. Steel is fairly easy to recycle and it maintains its strength and durability once it has been recycled. However, producing one ton of steel yields 1.8 tons of carbon dioxide, which contributes to the addition of greenhouse gasses in the atmosphere [5]. 

Overall, the production of snowboard materials is detrimental to the fragile ecosystems that this planet’s organisms have adapted to live in. The emission of greenhouse gasses through the production of these materials contributes to the greenhouse effect. Earth’s surface is warmed by the suns contact with the trapped heat and radiation in our atmosphere. Mining for graphite and bauxite defaces the surface and contaminates the air of our planet. The remaining materials used in snowboards such as: steel, epoxy resin, fiberglass, p-tex and PBT are produced by energy intensive, fossil fuel driven methods and are not benefitting our planet in any way, shape or form. Perhaps if mankind found less toxic methods of material extraction and production, our planet would not be suffering from rising global temperatures. 

Bibliography

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[2] "Base Repairs." Tognar Toolworks. Web. 5 Feb. 2016. <http://www.tognar.com/blog/base-repairs/>.

[3] "Basics of an Open Pit Mine." Basics of an Open Pit Mine. Web. 12 Feb. 2016. <http://www.mine-engineer.com/mining/open_pit.htm>.

[4] "Frequently Asked Questions." Where Does Aluminium Come From? Web. 14 Mar. 2016. <http://aluminium.org.au/FAQRetrieve.aspx?ID=42259>.

[5] "Local Environmental Issues." World Steel Association -. Web. 10 Feb. 2016. <https://www.worldsteel.org/steel-by-topic/sustainable-steel/environmental/local-issues.html>.

[6] "Materials and Design." 11 Jan. 2014. Web. 10 Feb. 2016. <http://www.donek.com/tech-info/materials-and-design/>.

[7] "Overview of Greenhouse Gases." Carbon Dioxide Emissions. Web. 10 Feb. 2016. <http://www3.epa.gov/climatechange/ghgemissions/gases/co2.html>.

[8] "Patent US20140336348 - Epoxy Resin Production." Google Books. Web. 10 Feb. 2016. <https://www.google.com/patents/US20140336348>.

[9] "Polybutylene Terephthalate (PBT)." Encyclopedia Britannica Online. Encyclopedia Britannica. Web. 14 Feb. 2016.

[10] "Ski and Snowboard Topsheet." Ski and Snowboard Topsheet. Web. 10 Feb. 2016. <http://snowboardmaterials.com/index.php/materials/top-sheet-material>.

[11] "What Aluminum Extraction Really Does to the Environment." RecycleNation. Web. 30 Jan. 2016. <http://recyclenation.com/2010/11/aluminum-extraction-recycling-environment>.

[12] "Your Ski and Snowboard Wax Could Be Seriously Harmful to You, Wildlife." TreeHugger. Web. 11 Feb. 2016. <http://www.treehugger.com/culture/your-ski-and-snowboard-wax-could-be-seriously-harmful-to-you-wildlife.html>.

Aspyn La Mond Walton 

Professor Christina Cogdell 

DES 40a

14-03-2016

Analyses of Embodied Energy of a Snowboard

    Snowboarding is arguably Americas favorite winter olympic sport, and has been a snowy past time for generations, originating around 1964 a surfer decided he wasn't going to let a little snow dampen his boarding spirit. His enthusiasm for the sport has grown into an international phenomenon and now millions of people worldwide enjoy shredding the snow with a variety of boards made with different techniques and disciplines. One snowboard manufacturer, Burton, is the forerunning producer and they experiment with many ways of making boards to try and reduce their environmental impact. Most people would be shocked to learn how much a single 11 lb board requires the same amount of energy to manufacture as charging an iPhone 13 times, and that isn’t even considering the energy used in materials transportation. What causes this seemingly mis-appropriation of power? To answer that question we must first go to the very beginning, at the very start of the universe itself. Okay, not that far, but to completely understand the energy needs of a snowboard, it must be understood what a rider needs from the board. 

    Good snowboards have a perfect mixture of rigidity and flexibility, and until recently the only material capable of this “goldy-locks” flex zone has been wood. The classic, age old, cut this down with axe wood, but companies like Burton recognize that if all seven billion of us go swing happy in the forrest we’ll run out oxygen faster than Sandra Bullock in Gravity, so they’ve spent countless hours developing a board that uses an alternative material yet remains energy efficient. Their solution to this complex problem is to use an aluminum honeycomb structure in the core of their snowboard dubbed, “Alumify.” Now, if you’re as up to date on the energy expenditure of basic construction materials as I now am (which since you're most like my TA, you are) then you're probably thinking to yourself, “wait a minute, aluminum is one of the most energy impactful material we use in the modern age,” and you’d be totally correct. However, because Burton is using purely recycled aluminum for their revolutionary core the energy usage plummets. This is because when recycling aluminum, the entirety of the metal can be reused [9], meaning the embodied energy rivals that of the classic wood core. 

    Even though Burton has solved their wood problem the energy expenditure remains the same. The rub here is sleeping with fishes. Well, bellow the fishes, in deep caverns of compressed carbon life that has decayed into what we call oil. We process that oil into plasticsfor various uses, in this case the top sheet and base of the snowboard. This is problematic because the process to change oil into plastic is so inefficient [12] it would make Mr. Scrooge beg for christmas future to make due on his promise of death. The 3 or so pounds of plastic protecting that recycled honeycomb pepsi core make up nearly 50% of the total embodied energy for the board weighing in around 85.3 MJ/kg and even worse than that is the oil based epoxy resin at 139.3 MJ/kg [8/11].  The most likely producer of this recycled fossil energy is DOW chemical, the largest producer and connoisseur of all things harmful to the planet. 

    Before delving even further down the tangent of mega corporations ruining the planet, let’s get a recap on the materials used in snowboard construction and their required energy. The manufacturing process starts with the core, in this case the aluminum core. Second, fiberglass is applied to both top and bottom of the core and adhered with the epoxy resin. Third the fiberglass coated core gets incased in a PBC (plastic) shell. Last is the application of the steel trim, and that completes the construction of a standard snowboard [10].

    So far we’ve been avoiding the inclusion of transportation into the energy calculation to focus purely on the energy encapsulated in the snowboard itself. But, what about all the other energy used in its life? Like transportation of its pieces or even the trips to the snow. For instance, the average rider can typically get 150-200 days [7] out of a standard quality board, and assuming this riders is a Davis resident (for example) that is around 40,000 miles, or 1569 gallons of gasoline with the 2015 average miles per gallon [cite]. 1569 is around 206683 MJ of embodied energy, or 11 million full iPhone charges [2/5/6]. The energy required for the manufacture of the actual board is negligible compared to outrageous amount of energy required to use it to full its full expectancy.  

    It doesn't stop there, however, once these boards have shredded their last flake of snow they often end up in local landfills for incineration which is an almost incalculable amount of energy. So by the time a snowboard makes it back to the ground it came from it has left a bigger footprint on this planet than the dinosaurs its plastic was made from.

[1]“Estimated Thickness, Weights, and Resin Amounts for Common Fiberglass Reinforcements." Fiberglass Coatings Inc. Web. 4 Mar. 2016. <https://www.fgci.com/pdf/commonmaterialthicknessesandweights.pdf>.

[2]“Convert Gallon to Megajoule - Conversion of Measurement Units." Convert Gallon to Megajoule. Web. 6 Mar. 2016.

[3]Hammond, Geoff. "INVENTORY OF CARBON & ENERGY (ICE)." University of BATH. Web. 4 Mar. 2016.

<http://perigordvacance.typepad.com/files/inventoryofcarbonandenergy.pdf>.

[4]“Fiberglass.” How Fiberglass Is Made. Web. 3 Mar. 2016. <http://www.madehow.com/Volume-2/Fiberglass.html>.

[5]Jeff. ": How Much Gas to Charge an IPhone?" Jeff's Lunchbreak. Web. 8 Mar. 2016.

[6]Naughton, Nora. "Average U.S. Mpg Edges up to 25.5 in May." Automotive News. 2015. Web. 7 Mar. 2016.

[7]SiKBOY. "Equipment Lifespan." Snowboarding Forum. Web. 6 Mar. 2016. <http://www.snowboardingforum.com/fashion/31540-            equipment-lifespan.html>.

[8]“Plastics and Energy Efficiency." The Plastic Industry Trade Association. The Plastic Industry Trade Association. Web. 6 Mar. 2016. <https://www.plasticsindustry.org/AboutPlastics/content.cfm?ItemNumber=792&navItemNumber=1124>.

[9]“Snowboard.” Wikipedia, the Free Encyclopedia. Web. 3 Mar.2016.

<https://en.m.wikipedia.org/wiki/Snowboard#Board_construction>.

[10]“Life Cycle of a Snowboard." Prezi.com. Web. 14 Mar. 2016. <https://prezi.com/uxpi4vjyzfo1/life-cycle-of-a-snowboard/>.

[11]Walsh, Justin M., and Gangaram Singh. "An eco-efficiency analysis of the snowboard manufacturing industry." International Journal of Sustainable Society 1.4 (2009): 364-382.

[12]Kelly, John M. "Ultra-High Molecular Weight Polyethylene*." Journal of Macromolecular Science, Part C: Polymer Reviews 42.3 (2002): 355-71. Web.

Marion Eng

Professor Cognell

DES 40A Winter 2016

March 14, 2016

Waste and Emission of the Life Cycle of Snowboards

Snowboarding is a popular wintertime sport that puts the joy of riding down a mountain at high levels of speed. Snowboarding is a relatively young sport; it has only been admitted to the Winter Olympic Games in 1998[1]. Since the beginnings of the sport, the production of snowboards increased due to rising popularity. Burton Snowboard, the leader of the snowboard manufacturing industry is the basis of this entire life cycle of materials, energy, and waste and emission[2]. With the increasing awareness of the depleting earth resources and the harm of production is to the environment, it is important to understand each step of the life cycle of goods. By understanding what goes into the different stages of the life cycle of the snowboard, which includes the extraction of raw materials, the production of secondary materials, the manufacture of the snowboard, the customers’ usages, and the disposal of the snowboard, the big picture of waste, byproducts, and emission on the unsustainability of production and its affects in the environment.

Acquiring the materials used to create a snowboards require extracting different compounds from the earth and refining them into usable ingredients. Both of these processes can release contaminants and harmful emission into the environment. In order to research the waste produced throughout the life cycle of a snowboard, the makeup of the snowboard must be known. Because there was no public information of where Burton Snowboard acquires their material for their snowboards, broad research of the different sources on the general materials was conducted. A typical snowboard is made up of different layers of various materials to optimize the flexibility, durability, and ability to pick up speed going down slopes. The multilayer configuration of the snowboard consist a core that can be made from wood or aluminum, fiberglass layers, a top sheet made of Ultra High Molecular Weight Polyethylene (UHMWPE), steel bindings at the side, vertical side walls made from acrylonitrile-butadiene-styrene (ABS)  and resin epoxy to hold everything together[1].

The core of the snowboard is made up of either a mixture of various woods or an aluminum honeycomb structure[1]. Depending on the type of snowboard, specific types of woods are used to enhance the flexibility and the weight of the boards. The extraction of the wood does not create any harmful waste, but the machinery used to cut down the tree uses electricity. Burning fossil fuels to create electricity releases CO2, nitrous oxides, and carbon monoxide. The aluminum honeycomb structure of is used to reduce the amount of aluminum used in the board. Aluminum processes require many steps, but the waste created are bauxite residue, mercury emission, and spent pot lining[3]. Bauxite residue is made up of varying level of iron oxides, titanium dioxide, silicon oxide, and other oxides.

The fiberglass layers sandwich the core to protect it and provide rigidity for a sturdy snowboard. Fiberglass is made from the melting of silica sand, limestone, kaolin clay, fluorspar, colemanite, and dolomite into liquid[4]. All of these are extracted from the earth by machinery that uses fossil fuel or electricity. The process of making fiberglass is typically clean with the exception of the release of styrene vapors when the resin dries[5].

The ABS side insulation layer also protects the core at the sides of the snowboard. ABS is created from the derivation of acrylonitrile, butadiene, and styrene[6]. Acrylonitrile is synthesized from propylene and ammonia, butadiene is created from fossil fuels, and styrene is med from ethylene and benzene. most the materials to make ABS is extracted from the raw material petroleum using stream cracking yielding the fuel oil, mixed C4, refined butadiene, hydrogen gas, ethane, propylene, benzene, ethylene, toluene, gasoline, and mixed xylene[7]. Many of these compounds are used in the other production of materials like UHMWPE. The ammonia used to make acrylonitrile is made from the Haber process[8]. Although this process creates no byproduct, the process is an energy glutton because it requires high temperate and high pressure in order to create ammonia. High energy means high gas emission from the production of energy. The burning of these materials deconstruct the structure and releases carcinogens into the air.

Metal production tend to the process that create the most waste and emission out of the snowboard materials. Steel is necessary for the side binding of the snowboard, but aluminum is optional for the core. Steel is made from iron ore heated with magnesium and oxygen; these raw materials are found on earth unaltered and is extracted using machinery. From the extraction of iron from the ore, it releases naphthalene, ammonium compounds, crude light oil, sulfur, and coke dust[9]. The impurity from the ore is the largest byproduct from the steel production. It consists of limestone and other impurities. This slag is typically sold to construction industry for reuse[10]. The last byproduct of steel production is the electric arc furnace (EAF) dust. This is sludge from steel production has three destinations: sold to other companies, end up being reused in factory, or dumped in the landfill[11].

The purpose of the UHMWPE base sheet is reduce the friction of the board to create a low traction, smooth riding snowboard [1]. UHMWPE is created by long chains of ethylene and its production does not have any byproducts[12]. Although, ethylene is extracted from steaming cracking fossil fuels which is mentioned in the ABS paragraph. The process of making UHMWPE leaves no residue and very cost effective[13].

The epoxy resin is used to permanently bind all the layers of the snowboard together. There are two parts to creating epoxy, a mixture of epichlorohyrin and bisphenol A, and a mixture of ammonia, ethylene dichloride, and sodium hydroxide[14]. Epichlorohyrin is made from a chloro-derivative of propylene extracted from petroleum and sodium hydroxide through a two-step process[15]. Byproducts from epichlorohyrin includes sodium chloride (commonly known as salt) and water. Both of these compounds are not harmful to the environment and used for production of different metals, and soda ash industry. The industrial production of alkyl-chloride byproducts only include hydrochloric acid which can be used for creating alkyl-chloride in a laboratory setting or for manufacturing of other materials. Sodium hydrochloride, the other material used to make epichlorohyrin, is produced by a chloralkali process. Sodium hydroxide byproducts include mercury and calcium carbonate[16]. The other compound to make the epoxy resin is bisphenol A. Bisphenol A, itself is harmful to the environment due to the interference of nitrogen fixing bacteria and is created from acetone and phenol[17]. Acetone and phenol are both created from benzene and propylene in the Cumene process[18]. As mentioned earlier on in this paper, these compounds are created from steam cracking from petroleum and byproducts are also noted. Together bisphenol A and epichlorohyrin makes the first part of the epoxy. The materials to the second part of the epoxy is mentioned throughout this paper.

During the manufacturing stage where all the materials are brought together to create a snowboard, no new compound is produced. Different types of machinery including band saw and drill are used to shape and form the snowboards. All of these tools are powered by burning of fossil fuel to created electricity. Like mention earlier on, burning of fossil fuels releases harmful gases into the air. Other waste includes the scraps of wood and epoxy shaved off the snowboard.  

After the snowboard has finished production, it has to be distributed to different sale outlets. The snowboards are shipped in freight boats, cargo planes, or ground shipping. The rate of fuel consumption depends on the weight of the snowboards. By using the fuel, gas emission is released into the air. Burton snowboards for example main market share is in the United States, but their factory is located in Austria[20]. The amount of fuel used to transport the snowboard internationally added up per snowboard making the rate of energy consumption higher than it was in Vermont.

At the end of the snowboard product life cycle, there are two options of disposal. Most snowboards tend to end up in landfill in its entirety due to the difficulty to dismantle the recyclable parts. If the snowboard can be dismantled, the UHMWPE, steel, aluminum can be recycled, while the epoxy and the ABS can be dumped in the landfill. The second option is incineration to decrease space in the landfill. Although this option reduces the amount of materials that goes into the landfill, the burning of the epoxy, UHMWPE, and ABS releases carbon monoxide, dioxins and furans into the air[21].

From the beginning and end of the life cycle of the snowboard, it shows the how unsustainability of production. Instead of being a life cycle, it is more like a linear line of where the snowboards will end up. By researching all that goes into making the different type of materials, the energy usage of manufacture and distribution, and the disposal of the snowboard the realization of the consumption of goods, cannot continue on without finding greener ways to reduce waste creating from manufacturing goods. Although there is a good overlap of the same raw material to make the secondary materials for the snowboard, unless the cycle goes full circle, this method of production cannot go on forever.

Bibliography

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[2]Marquardt, Katy. "Burton Snowboards Is King of the Hill." USA News, 19 Sept. 2008. Web. <http://money.usnews.com/money/business-economy/small-business/articles/2008/09/19/burton-snowboards-is-king-of-the-hill>.

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[7]Picciotti, Marcello. "Novel ethylene technologies developing, but steam cracking remains king." Oil and Gas Journal 95.25 (1997).

[8]Modak, Jayant M. "Haber process for ammonia synthesis." Resonance 7.9 (2002): 69-77.

[9]Russell, Clifford S., and William J. Vaughn. Steel production: processes, products, and residuals. Routledge, 2013.

[10]Shi, Caijun. "Steel slag-its production, processing, characteristics, and cementitious properties." Journal of Materials in Civil Engineering 16.3 (2004): 230-236.

[11]Southwick, Larry M. "Still no simple solution to processing EAF dust." Steel Times International 34.2 (2010): 43.

[12]Hinrichsen, G., et al. "Production and characterization of UHMWPE fibers/LDPE composites." Mechanics of composite materials 32.6 (1996): 497-503.

[13]Kelly, John M. "ULTRA-HIGH MOLECULAR WEIGHT POLYETHYLENE*." Journal of Macromolecular Science, Part C: Polymer Reviews 42.3 (2002): 355-371.

[14]Carlberg, Philip J., et al. "Epoxy resin production." U.S. Patent No. 8,907,137. 9 Dec. 2014.

[15]Kasai, Naoya, Toshio Suzuki, and Yoshiro Furukawa. "Chiral C3 epoxides and halohydrins: their preparation and synthetic application." Journal of Molecular Catalysis B: Enzymatic 4.5 (1998): 237-252.

[16]Kasai, Naoya, Toshio Suzuki, and Yoshiro Furukawa. "Chiral C3 epoxides and halohydrins: their preparation and synthetic application." Journal of Molecular Catalysis B: Enzymatic 4.5 (1998): 237-252.

[17]Sato, Yoshiki, et al. "Degradation behaviour and recovery of bisphenol-A from epoxy resin and polycarbonate resin by liquid-phase chemical recycling." Polymer degradation and stability 89.2 (2005): 317-326.

[18]Hamada, Rei, et al. "One-step gas-phase catalytic oxidation of benzene to phenol with molecular oxygen over Cu-supported ZSM-5 zeolites." Physical Chemistry Chemical Physics 5.5 (2003): 956-965.

[19]Huang, Y. Q., et al. "Bisphenol A (BPA) in China: a review of sources, environmental levels, and potential human health impacts." Environment international 42 (2012): 91-99.

[20]Bradstreet, Kailee. "Burton's Local Manufacturing Shifts To Austria Facility | Transworld Business." Transworld Business. 16 Mar. 2010. <http://business.transworld.net/news/burtons-local-manufacturing-shifts-to-austria-facility/>.

[21]Fu, P. Q., et al. "Molecular characterization of urban organic aerosol in tropical India: contributions of biomass/biofuel burning, plastic burning, and fossil fuel combustion." Atmos. Chem. Phys. Disc 9.21 (2009): 669-21.