ITT Technical Institute
Environmental Impact of Aviation
Aviation contributes approximately 2 percent of total greenhouse gas emissions, a figure which is projected to grow through 2050. Although fuel efficiency has improved by nearly 16 percent since the 1990s, future technologies—including better flight patterns, more-efficient engines, and alternative fuels—have promise for further emissions reductions. The profitability challenges of the early twenty-first century, however, affect the industry's ability to invest in new technology. (Hill, 2010 17-22) Globally, air travel was estimated to be responsible for approximately 480 million tons (~435 million metric tons) of carbon dioxide emitted into the atmosphere in the year 2000. With the rapidly increasing onset of global warming, high carbon intensive industries (such as airlines) must find sustainable strategies to maintain growth and profitability or risk further damage to the world's environment. (Hill, 2010 17-22) Scientific analysis and debate concerning greenhouse gases and global warming have brought air quality to the forefront in the environmental community and general public concern. The future FAA 5050 Handbook will most likely consider assessment guidelines for potential impacts resulting from emissions of air toxics from aircraft engines, ground vehicles, and other point sources at airports. Although jet engines built after 1982 emit about 85 percent less unburned hydrocarbons than jet engines built in the 1970s, and CO emissions have decreased by 70 percent, increased operations have significantly affected air quality. Air carrier airports have begun to face the task of evaluating their contributions to air quality, in accordance with the EPA General Conformity Rule within nonattainment areas. EAs prepared in the new millennium will also focus on source emitters on the ground (idling aircraft, auxiliary power units, ground support equipment, vehicular traffic) as well as the aircraft emissions in cruise. Subsonic and supersonic aircraft emissions affect air quality in different manners, both of which have an impact on the global atmosphere. (Hill, 2010 17-22) Worldwide, passenger traffic is expected to grow 5% annually at least to 2015. Fuel use is only projected to grow 3% per year due to fuel efficiency improvements. The earth’s temperature could increase 1.6 degrees F by 2050, and the aviation contribution to that is estimated to be 0.09 degrees. Aircraft and engine technology improvements could increase fuel efficiency by 20% by 2015, and 40-50% by 2050. In particular there is work to reduce Nox emission by 70% during takeoffs and landings. Operational improvements may decrease fuel burned in aviation activities by 6-18%, with an additional 6-12% coming from air traffic management improvements. (Environmental Impact of Aviation Operations, 2005) The overall expected improvements in technology are not expected to completely offset the general increase in the numbers of flights and aircraft operations in the next 50 years. Fuel dumping, or jettisoning of fuel in-flight is performed in situations where the aircraft gross weights needs to be reduced in order to permit a safe landing. Many aircraft take off with gross weights above their designed landing weight. An emergency or diversion then could necessitate landing prior to their flight plan, leading to having to land over their gross weight. Fuel is then jettisoned in flight to reduce the weight of the aircraft. Most of the fuel that is dumped turns into vapor within a few minutes. If jettisoned above 5000 feet in above freezing temperature calculations show that 98% will evaporate before reaching the ground. The fuel vapors rapidly dissipate and diffuse. This could contribute to...