HornWhyWorry?




 * [FLIGHT] **

** How the journey skyward could be altering the Earth left behind. Massive amounts of energy and material put into the construction and testing of airplanes, as well as normal operation. Massive infrastructure network that supports a form of transportation not much more efficient than single passenger automobile traffic. Detrimental interaction with organisms and pollution of local and global ecosystems. **


 * [FLIGHT - Introduction ] **

At first glance, air travel appears to be one of the most environmentally friendly forms of transportation. Air travel is the epitome of public transportation in a theoretical sense, meaning that massive groups of people use the same vehicle. However, there are many factors not analyzed or in some cases simply realized in common analysis of the environmental impact of air travel. Only recently, like in many areas of manufacturing, has the life cycle analysis of carbon footprint been explored, revealing new questions regarding airline infrastructure and traffic, not just technologies. There are also concerns in the areas of pollution and habitat intrusion. The key issue however rests with global trends showing an increase in air traffic volume. “Global air travel growth rates have been in the order of 5-6% per year in the period 1970-2000; air transport volume is now five times as large as it was in 1970. Globally, some 42% of all international tourist arrivals are now by air.” [1]


 * [FLIGHT – Energy Consumption ] **


 * [ MATERIAL ]**

Beginning the life cycle analysis of air travel requires an investigation as to the source of the materials that comprise the aircraft. Each aircraft is different but, “Jets used by airlines have more composite materials than ever before, although aluminum is still the major component in airliner construction.” [2] Briefly, aluminum is one of the most difficult and energy intensive metals to produce. It isn’t found in pure form and must be refined from ore, typically bauxite, which is gathered typically by a process of open-pit mining that destroys landscapes and ecosystems. To refine the aluminum, two high temperature, meaning high-energy input, processes transform it to its pre-molded powder form: the Hall-Heroult Process, and the Bayer Process. The move towards a higher percentage of composite materials decrees the aluminum required but also increases the role of petroleum through petroleum based materials.

**[ MANUFACTURING ]**

Because of the scale of the airplane, manufacturing is a very physically engaging process. Planes are assembled from larger manufactured pieces, many times pieces machined on premises. This means large staff is required to continuously operate on the behemoth machines, as well as large means of transportation of parts around company campuses and from other locations. “Aircraft manufacturing, infrastructure operation, and fuel production produce emissions from aircraft that are 1.2 times larger than operational emissions. The direct electricity requirements and truck and rail transport are the key components in aircraft manufacturing.” [3]

**[ OPERATION + INFRASTRUCTURE ]**

While “…in an average trip involving air transport, 60-95% of its contribution to global warming will be caused by the flight,” [4] the fact remains that there is a vast network of culture-less zones, airports, which involve transportation practices revolving around gas-powered automobiles. Except for a few new efficient airports, the buildings themselves are large constantly powered entities which draw massive amounts of energy for air-conditioning, lighting, and systems operations. The operational efficiency of an aircraft is difficult to compare to other forms of transportation because of the distances travelled and number of passengers aboard. However, “using this […] occupancy rate of 2 for comparison, the A380 [Airbus] uses an estimated 60% more fuel per passenger km than the small car used…” [5] Geography has a large part in fuel efficiency as well. European countries with interlocking boundaries all have separate air management systems, making it very difficult to fly in a straight line across countries.


 * [FLIGHT – Emissions ] **


 * [ GHG ]**

“…most emissions are released at 10-12 km height in the upper troposphere and lower stratosphere, where they have a larger impact on ozone, cloudiness and radiative forcing potential than they do at the earth’s surface.” [6] CO2 is actually not one of the primary concerns of aircraft emissions. However, Nitrous Oxides are because they are ozone depleting gases, whose effects are amplified due to the high altitudes at which they are released.


 * [ CONTRAILS ]**

The discussion regarding airplane contrails is an interesting one. While there is some debate over their actual impact on global warming, there are many studies that actually support it has a negative effect on warming. Because of the creation of atmospheric white clouds, more sunlight actually reflects off into space allowing less energy to be absorbed and reflected back into the atmosphere. Contrails are formed by the freezing of condensation left behind by the burning of hydrocarbons at high altitudes. One study conducted by a group at the University of Wisconsin analyzed data from the three days following 9-11 where plane traffic was grounded. They came to the conclusion that “the diurnal temperature range averaged across the United States was increased during the aircraft grounding period […] We argue that the absence of contrails was responsible for the difference between a period of above-normal but unremarkable DTR and the anomalous conditions that were reported.” [7] Essentially, during the period without contrails, more energy was absorbed during the day, creating hotter days and a greater diurnal shift in temperatures.


 * [FLIGHT – Pollution + Ecology ] **


 * [ DE-ICING TOXINS ]**

Large amounts of liquid de-icing spray are applied to the airplanes before every flight. Some of these sprays are designed to remain on the plane as an icing preventative, and it is these secondary sprays that contain unique compounds of which the toxicity is unknown. “The bases of all de-icing fluids are propylene and ethylene glycol, which are also used as antifreeze in cars, However, anti-icers include additional ingredients, which are manufacturer-specific trade secrets….” [8] This makes it difficult to determine the role these toxins are playing in local hydro-ecologies; however a number of samples from airports around the US are showing unusual signs of organism deformity, sickness, and death.


 * [ BIRD INTERFERENCE ]**

The most recent event of animal interference is of course the landing of the US Airways plane into the Hudson River. Luckily, a talented individual was able to safely land the plane, however the issue of who is being more impacted by these interactions remains in question. Airports have numerous measures in place to avoid bird-caused casualties of passengers; however the bird populations continuously appear to come second. While programs at airports are established to carefully control bird populations, they focus on relocation of habitats, not successful integrated design creating as light an impact as possible.


 * [ NOISE ]**

The primary pollutant recognized by the common public over the past 20 years has been noise pollution from airports. While the supersonic commercial jet, the Concord, is no longer operational, regular jet engines still add high-decibel audible noise to local areas surrounding airports, which is a considerable health hazard to individuals.


 * [FLIGHT – Solutions ] **

- More efficient engines like the new Pratt & Whitney geared turbofan engine, which is slated to burn 12 to 15 percent less fuel than previous engines. - Decrease in international air travel by focusing on rail and ground travel inside Europe - Smarter system of air traffic controlling and cooperation amongst bordering nations, creating more direct flights for decreased fuel consumption. - Some airports have taken critical steps towards fighting toxin run-off. “BWI’s runoff reclamation project cost the airport more than $10 million. But these pads reclaim up to 80 percent of the estimated 35,0000 gallons of fluid lost per day, which the airport can recycle – saving money, as well as helping the environment…” [9] - Increased Biofuel research. Specifically a project currently under the control of DARPA which is utilizing algae resources to create a 50% algal, 50% petroleum fuel for all military aircraft. The program is actually scheduled for a 2013 launch. - Decreased weight through material change. “Boeing says composite materials make up nearly 50 percent of the plane, which can carry as many as 330 people, making it far lighter than other planes its size. It is 20 percent more fuel-efficient and produces 20 percent fewer emissions than similarly sized aircraft, company officials say. [10]


 * [FLIGHT – SOURCES CITED ] **

**[1]** Gössling, Stefan, and Paul Peeters. "'It Does Not Harm the Environment!' An Analysis of Industry Discourses on Tourism, Air Travel and the Environment." //Journal of Sustainable Tourism// 15, no. 4 (July 2007): 402-417. //Business Source Premier//, EBSCO//host// (accessed September 13, 2010) **[2]**”Greener Flight.” (accessed September 13, 2010)  []

**[3]** Chester, and Arpad Horvath. “Environmental assessment of passenger transportation should include infrastructure and supply chains.” //Environmental Research Letters// 4,(June 8, 2009) (accessed September 13, 2010) **[4]** Gössling **[5]** Gössling **[6]** Gössling **[7]** Carleton, Travis, and Ryan Lauritsen. “Contrails reduce daily temperature range: A brief interval when the skys were clear of jets unmasked an effect on climate.” //Nature// 418 (August 8, 2002) (accessed September 13, 2010) **[8]** Sally Adee. “Anti-icers make airport runoff toxic.” //Geotimes// (January 29, 2007) (accessed September 13, 2010) **[9]** Sally **[10]** Dave Demerjian. “Greener Jet Engine Could Reduce Aviation’s Carbon Footprint,” (accessed September 13, 2010), []


 * [FLIGHT – ADDITIONAL SOURCES ] **

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 * [FLIGHT – IMAGES ] **

[|U.S. Airways Crash in Hudson]

[|Jet Contrails]

[|Boeing 777 Dreamliner Wing Test]



[|Boeing 777 Dreamliner Construction]

[|U.S. Flight-Path Visualization]