AVIATION & THE ENVIRONMENT Ian A. Waitz Professor and Deputy Head Department of Aeronautics and Astronautics Massachusetts Institute of Technology ? 2003 Waitz 1 LECTURE OUTLINE ? Overview of environmental effects of aircraft ? Aircraft noise – Impacts and regulatory issues – Technology trends ? Aircraft pollutant emissions – Impacts and regulatory issues – Technology and emissions trends ? Summary and references ? 2003 Waitz 2 Noise None applicable Compatibility with nearby land uses Air quality Most serious problem currently Most serious problem in the future Wetlands 29 AIRPORT Noise 22 RANKING OF ENVIRONMENTAL 12 Water quality ISSUES Water Quality 6 6 Air Quality Current and Future 16 2 Compatibility with Land-use limitations 4 1 None Applicable 0 0 Wetlands 2 0 5 10 15 20 25 30 35 Number of airports Most serious problem currently Most serious problem in future Source: GAO’s survey of the nation’s 50 busiest commercial service airports. ? 2003 Waitz (GAO, 2000) 3 CHARACTERISTICS OF NOISE AND EMISSIONS ISSUES ? Noise – Local – Persistence = minutes – Well-established metrics – Impacts: annoyance, sleep disturbance, domestic animals?, endangered species?, health impacts? ? Emissions – Local, regional, global – Effluents: CO 2 , H 2 O, NO x , CO, VOC’s, soot, others – Persistence = 1 day -1000 years – Drastic change in public/scientific perception and regulatory frameworks – Impacts: human health, ecosystem health ? 2003 Waitz 4 AVIATION ENVIRONMENTAL IMPACTS ? “EXTERNALITIES” – A large fraction of current aviation health and welfare impacts are real costs to society but are not accounted for by the providers or users of the service “The government’s objectives for aviation are that…the polluter should pay and aviation, like other industries, should meet its external costs, including environmental costs.” (From UK Department of Transport, Aviation and the Environment, Using Economic Instruments, March 2003) ? 2003 Waitz 5 EXTERNAL COSTS OF AVIATION VALUATION SOCIAL INSTITUTIONAL BASIS (industry + affected public) (regulatory policy) Impact Area (objective) Total $ $ / capita Total $ $ / capita % of Total $ addressed by regulation Noise $ 26B $ 2100 $ 2.9B $ 6000 11% (quiet environs) Air Quality $ 11B $ 140 $ 2.5B $ 30 22% (safe air) Climate Change ~$100B $ 345 $ 0.0B $ 0 0% (stable climate) TOTAL ~$137B $ 5.4B 5% ? Regulatory framework currently accommodates ~ 5% potential internalization of external costs ? Noise cost per capita greater than emissions aligns with public opinion and institutional attention – Most vociferous opposition to noise, but air quality becoming more of an issue (GAO 2000) >>PRELIMINARY ESTIMATES ONLY<< Lukachko, 2003 ? 2003 Waitz 6 GROWTH IN MOBILITY PROVIDED BY U.S. AVIATION INDUSTRY (DOT Form 41 data) Fastest Growing Mode of Transportation (4-6%/yr) Revenue Passenger Miles Performed by All Airlines Operating Aircraft with >60 Seats 8E+11 7E+11 6E+11 5E+11 4E+11 3E+11 2E+11 1E+11 0 1965 1970 1975 1980 1985 1990 1995 2000 2005 Year ? 2003 Waitz 7 AIR TRAVEL PROJECTED TO BE FASTEST GROWING MODE OF TRANSPORTATION (4-6%/yr) - DRIVEN BY POPULATION AND GDP GROWTH, AND AVAILABLE DAILY TRAVEL TIME - Automobiles Buses Railways Aircraft 1960 1990 2020 2050 5.5×10 12 RPK 23 ×10 12 RPK 54 ×10 12 RPK 105 ×10 12 RPK Source: Schafer et al. (1998), GDP/cap growth rates from IPCC IS92a Scenario ? 2003 Waitz 8 MOBILITY AND THE ENVIRONMENT “ Environmental issues are likely to impose the fundamental limitation on air transportation growth in the 21st century. ” U.S. National Science and Technology Council, 1995 72% 28% 25% 75% Expansion Projects Delayed due to Environmental Issues Source: GAO (2000) survey of 50 busiest commercial airports. N=33 for this question, 1 airport did not respond. 28% (9 airports) with no impact projects delayed at 72% (23 airports) Expansion Projects Cancelled or Indefinitely Postponed due to Environmental Issues 25% (12 airports) with at least 1 project affected no impact at 75% (36 airports) Source: GAO (2000) survey of 50 busiest commercial airports. N=50 for this question, 2 airports with no projects planned. ? 2003 Waitz 9 AIRPORTS ARE REACHING CAPACITY LIMIT Figure 2: Anticipated Date for Airports to Reach Capacity Number of airports 14 13 11 5 2 8 7 4 0 1 2 3 4 5 6 7 8 9 10 11 12 13 Already 1-2 years 3-4 years 5-6 years 7-9 years 10 or Other at or more above years capacity Estimated time to reach capacity Source: GAO’s survey of the nation’s 50 busiest commercial service airports. ? 2003 Waitz 10 DOD ENCROACHMENT ? External factors such as urbanization, increasing environmental restrictions, and competition with civilian demands on airspace, land, seaspace, and radio frequencies “The overall trends are adverse because the number of external inputs is increasing, and the readiness impacts are growing. Future testing and training needs will only further exacerbate these issues, as the speed and range of test articles and training scenarios increase…” (DOD Sustainable Ranges Outreach Plan, SROC) Examples: JSF basing, Oceana operations, Navy in Japan ? Senior Readiness Oversight Council (SROC) action plans: – Endangered species, ordnance, frequency encroachment, the maritime sustainability, airspace restrictions, air quality, airborne noise and urban growth ? House of Representatives proposal (2002): National Security Impact Statement with all Environmental Impact Statements ? 2003 Waitz 11 REGULATIONS: BALANCING PUBLIC GOALS ? Economy and Mobility vs. National Security vs. Environment ? State vs. National interests and control ? Federal Noise Control Act + local noise restrictions – Commercial yes – Military no (Nat. Sec. Exemption, but NEPA EIS) ? Federal Clean Air Act + State Implementation Plans – Military yes (General Conformity Rule) – Commercial “no” (Interstate Commerce & Trade exemption) ? Endangered Species and Marine Mammal Protection Acts – Military “yes” (Nat. Sec. Exemption, but never used) – Commercial yes ? 2003 Waitz 12 GROWTH OF ENVIRONMENTAL REGULATION Reflects increasing environmental impacts and increasing valuation of the environment Materiel Developer’s Guide for Pollution Prevention, Cumulative Number of Federal Environmental Laws World-wide Civil Aircraft Noise Restrictions NAP Charges Quotas Budgets CH2 PO CH2 Rest. CH3 Rest. 1970 0 50 100 150 200 250 300 350 400 1980 1990 Year Number of Restrictions 2000 Curfews Levels Army Acquisition Support Office, 1994 www.boeing.com ? 2003 Waitz 13 AIRCRAFT REGULATIONS - Local , National, International - ? Noise – Certification standards – Phase-outs – Curfews – Flight control – Landing fees – Ticket taxes ? Emissions – Certification standards – Phase-outs – Limited local rules in place ? 2003 Waitz 14 LECTURE OUTLINE ? Overview of environmental effects of aircraft ? Aircraft noise – Impacts and regulatory issues – Technology trends ? Aircraft pollutant emissions – Impacts and regulatory issues – Technology and emissions trends ? Summary and references ? 2003 Waitz 15 AIRCRAFT NOISE GENERATION AIRFRAME NOISE ENGINE NOISE SONIC BOOM? ATMOSPHERIC PROPAGATION SPECTRUM, MAGNITUDE, DIRECTIVITY, DURATION FREQUENCY OF OCCURENCE, TIME OF DAY, LOCATION HUMAN ANNOYANCE ? 2003 Waitz 16 NOISE EFFECTS ON PEOPLE (FICON, 1992) ? 2003 Waitz 18 Effects Hearing Loss Annoyance Day- Night Average Sound Level in Decibels Qualitative Description % of Population Highly Annoyed Average Community Reaction General Community Attitude Towards Area 75 and above May begin to occur 37% Very Severe Noise is likely to be most important of all adverse aspects of the community environment 70 Will not likely occur 22% Severe Noise is one of the most adverse aspects of the community environment 65 Will not occur 12% Significant Noise is one of the adverse aspects of the community environment 60 Will not occur 7% Moderate to slight Noise may be considered an adverse aspects of the community environment 55 and below Will not occur 3% Moderate to slight Noise considered no more important than various other environmental factors COMMERICAL AIRPORT NOISE EXPOSURE MAP (DNL levels) (INM, 1999) ? 2003 Waitz 19 NOISE IMPACT TRENDS ?Phase-out –55% of U.S. fleet –94% reduction in impact –During 6X mobility growth –$10B US cost – –TECHNOLOGY foundation ?$1B/yr in US for sound abatement – –Low cost effectiveness $43/person/DNLdB $960/person/DNLdB ? 2003 Waitz 20 COMMERCIAL AND MILITARY NOISE IMPACTS Norfolk Intl. Airport 210 TO/day Oceana 121 TO/day 7 FCLP/day Fentress 20 TO/day 354 FCLP/day http://www.norfolkairport.com, http://www.nasoceana.navy.mil/aicuz ? 2003 Waitz 21 AIRCRAFT NOISE TECHNOLOGY TRENDS ? 2003 Waitz 22 AIRCRAFT NOISE SUMMARY ? Difficult connection between human annoyance and physics – Public becoming more sensitive to aviation noise – Relatively mature regulatory history ? Step changes in fleet unlikely ? Increased commercial certification stringency likely but probably within current technological capabilities ? Growing problem for the military ? Local restrictions make noise a product differentiator – For GE-90 powered B-777 (-6EPNdB cumulative relative to other engines) twice as many t/o and landings allowed at Heathrow – Manufacturers willing to trade 2% fuel burn for 2 dB (A380) ? 2003 Waitz 23 LECTURE OUTLINE ? Overview of environmental effects of aircraft ? Aircraft noise – Impacts and regulatory issues – Technology trends ? Aircraft pollutant emissions – Impacts and regulatory issues – Technology and emissions trends ? Summary and references ? 2003 Waitz 24 EMISSIONS IMPACTS ? Local air quality (NO x , CO, UHC, PM) – Focus of current regulations ? Regional/global atmospheric effects 1) Stratospheric ozone depletion (time-scale=10 years) – Largely a concern for supersonic aircraft (NOx) 2) Climate change (time-scale = 100-1000 years) – Subsonic and supersonic aircraft – CO 2 and H 2 O – NO x through ozone production – Particulates (SO x and soot) through heterogeneous chemistry and cloud nucleation ? 2003 Waitz 25 AIRCRAFT ENGINE EXHAUST ? Composition – Reservoir and primary combustion products CO 2 , H 2 O, N 2 , O 2 : O(10000-100000) ppmv – Secondary products and pollutant emissions CO, NO x , HC, soot: O(1-100) ppmv – Trace species constituents NO y , SO x , HO x : O(0.0001-0.1) ppmv ? Most constituents play some role in atmospheric processes – e.g. If 100% of SO 2 in engine oxidizes to SO 3 it may double stratospheric ozone depletion – Primary and secondary species relatively well-understood – Relative magnitudes and engine/operations effects on trace species poorly characterized ? 2003 Waitz 26 LOCAL AIR QUALITY ? Approx. 1% of US mobile source NO x emissions are from aircraft ? NO x , particulate matter, VOCs, CO -- ozone – Lung function, cardiovascular disease, respiratory infection ? 2003 Waitz 27 28? 2003 Waitz PM-10 Lead CO Ozone SO2 Notes: Incomplete data, not classified, and Section 185(a) areas are not shown. Ozone nonattainment areas on map based on pre-existing ozone standard. Nonattainment designations based on revised 8-hour ozone standard will not be designated until 2000. PM-10 nonattainment areas on map are based on pre-existing PM-10 standards. Nonattainment designations based on revised PM-10 standards have not yet been made. Source: U.S. EPA, National Air Quality and Emissions Trends Report, 1997. LOCATION OF “NON-ATTAINMENT” AREAS FOR CRITERIA POLLUTANTS AS OF SEPTEMBER, 1998 (Chang, 1999) % reg mobile source emiss AIRCRAFT CONTRIBUTION TO REGIONAL MOBILE SOURCE NO X EMISSIONS AT SELECTED US CITIES IS ESTIMATED TO INCREASE Estimated commercial aircraft contribution to regional mobile source emissions of NOx 12 10 8 6 4 2 0 LA DC Atlanta Boston Charlotte Chicago Houston NY Phila. Phoenix 1990 2010 Source: Table 4-2, EPA 420-R -99-013, "Evaluation of Air Pollutant Emissions from Subsonic Commercial Jet Aircraf t," April, 1999 (Chang, 1999) ? 2003 Waitz 29 30? 2003 Waitz AIRCRAFT AND OZONE (NOAA, NASA, UNEP, WMO, “Scientific Assessment of Ozone Depletion: 1994”) ? Aircraft: NEGATIVE EFFECT AT ALL ALTITUDES – Subsonics: +0.9% total column ozone (global warming) – Supersonics (1000, < 5% of fleet): -1.3% total column ozone – Combined fleet: -0.4% total column ozone (IPCC, 1999) SCIENTIFIC UNDERSTANDING IN 2003 vs. 1999 Green bars are updated values, with arrows updated uncertainty. ? 2003 Waitz 32 NOTES ON CLIMATE CHANGE IMPACTS ? Burning a gallon of fuel at 11km has about double the radiative impact of burning a gallon of fuel at sea-level ? Burning a gallon of fuel at 19km has about 5 times the impact at sea-level ? CO 2 is not the biggest global concern (potential impacts from contrails and cirrus clouds are greater). ? Large imbalance between northern and southern hemisphere ? Improving engine efficiency tends to make NOx and contrails worse ? High uncertainty ? 2003 Waitz 36 THE ROLE OF TECHNOLOGY: CHARACTERISTICS OF AVIATION SYSTEMS ? Safety critical ? Weight and volume limited ? Complex ? 10-20 year development times ? $30M to $1B per unit capital costs ? 25 to 100 year usage in fleet ? Slow technology development and uptake ? 2003 Waitz 37 TECHNOLOGY CHOICES: BOEING “Boeing is focusing its product development efforts on a super efficient airplane. This is the airplane that airline customers around the globe agree will bring the best value to an industry in need of improved performance. The advanced technologies that allowed the Sonic Cruiser configuration to provide 15 to 20 percent faster flight at today’s efficiencies now will be used to bring 15 to 20 percent lower fuel usage at the top end of today’s commercial jet speeds. Boeing believes that in the future airlines will again be interested in faster flight and we will be ready with a concept and technologies to meet this need.” (www.boeing.com, March, 2003) ? 2003 Waitz 38 COMMERCIAL vs. MILITARY FLEET TRENDS ? Demand growth for civil aviation (3.8%/year in US) ? Military fleet contraction ? Ops tempo (4.3/day commercial, 0.35/day military) Number of Aircraft Flights/day ? 2003 Waitz 40 FUEL CONSUMPTION TRENDS Aircraft responsible for 2%-3% of U.S fossil fuel use ? 2003 Waitz 41 COMMERCIAL AIRCRAFT EFFICIENCY Average Age = 13 yrs ? 2003 Waitz 42 MILITARY AIRCRAFT FUEL BURN Average Age 21 yrs ? 2003 Waitz 43 ENERGY EFFICIENCY ? Function of performance of entire system – Aircraft technology (structures, aerodynamics, engines) – Aircraft operations (stage length, fuel load, taxi/take- off/landing time, flight altitude, delays, etc.) – Airline operations (load factor) ? Each component of system can be examined independently for reduced fuel burn and impacts on local air quality and regional/global atmospheric effects ? 2003 Waitz 44 ?? ?? RANGE EQUATION Technology and Operations Stage Length VLD g SFC W W W W fuel payload structure reserve = ( ) ? + + + ? ? ? ? ? ? ln 1 = Technology = Operations Efficiency W StageLength W ASK kg Stagelength seats payload fuel fuel W g f ∝ = , # Use data to separate effects and understand influences of technology ? 2003 Waitz 45 TRENDS IN LOAD FACTOR Load Factor 0.8 0.7 0.6 0.5 0.4 0.3 0.2 0.1 0.0 Regional Jets Turboprops Large Aircraft 1965 1970 1975 1980 1985 1990 1995 2000 Year Babikian, Raffi, The Historical Fuel Efficiency Characteristics of Regional Aircraft From Technological, Operational, and Cost Perspectives, SM Thesis, Massachusetts Institute of Technology, June 2001 ? 2003 Waitz 46 FLIGHT AND GROUND DELAYS Ratio 1.0 0.9 0.8 0.7 0.6 0.5 0.4 0.3 0.2 0.1 0.0 Airborne to Block Hours Minimum Flight to Airborne Hours Mininum Flight to Block Hours 1965 1970 1975 1980 1985 1990 1995 2000 Year ? 2003 Waitz 47 HISTORICAL TRENDS Aerodynamic Efficiency L/D max 25 20 15 10 5 0 1955 1960 1965 1970 1975 1980 1985 1990 1995 2000 abikian et al. (2002) Data Unavailable For: EMB-145 FH-227 BAE RJ85 SA-226 CV-600 DHC-7 Turboprops CV-880 Nihon YS-11 Regional Jets Beech 1900 DHC-8-100 Large Aircraft CV-580 L-188 DHC8-300 D328 J41 ATR42 BAE-ATP ATR72F27 BAC111-200/400 B767-200/ER S360 J31 SA227 S340A F28-1000 F28-4000/6000 BAE146-100/200/RJ70 B727-200/231A BAE-146-300 B757-200 F100 B747-400 RJ200/ER B777 B707-100B/300 B707-300B B737-100/200 L1011-1/100/200 A300-600 DC9-30 B737-300 DC10-40 MD11 B737-400 A320-100/200 A310-300 DC10-30 L1011-500 B767-300/ER B747-100/200/300 DC10-10 MD80 & DC9-80 EMB120 B737-500/600 B Year ? 2003 Waitz 48 HISTORICAL TRENDS Engine Efficiency TSFC (mg/Ns) 30 25 20 15 10 5 0 B707-300 B720-000 B727-200/231A F28-4000/6000BAC111-400 DC9-40 BAE146-100/200/RJ70 CV880 F28-1000 BAE-146-300 F100 RJ85 B737-100/200DC9-30 DC9-10 DC9-50 MD80 & DC9-80 B737-300 D328 EM170 RJ200/ER F27 CV600 DC10-30 DC10-40 L1011-500 B767-200/ER MD11 B747-400 B737-400 B737-500/600 A300-600 B767-300/ER B757-200 L1011-1/100/200 B747-100 B747-200/300 DC10-10 EMB145 EMB135 RJ700 J31L188A-08/188C A320-100/200A310-300 B777 D328 J41 ATR72 DHC7 S360 B1900 CV580 SA226 SA227 EMB120 ATR42 DHC8-300 BAE-ATP DHC8-100 DHC8-400 Turboprops S340A bikian et al. (2002)Ba Regional Jets Large Jets New Regional Jet Engines New Turboprop Engines 1955 1960 1965 1970 1975 1980 1985 1990 1995 2000 2005 Year ? 2003 Waitz 49 HISTORICAL TRENDS Structural Efficiency OEW / MTOW 0.70 0.60 0.50 0.40 0.30 0.20 0.10 0.00 DC9-40 B737-100/200 B727-200/231A DC9-10 DC10-10 BAC111-200 F28-1000 BAC111-400 F27 FH227 CV600 L188A-08/188C DC10-40 DC9-50 MD80 & DC9-80 B767-200/ER B777 B747-400 B737-400 B737-500/600 A320-100/200 A300-600 A310-300 B767-300/ER B737-300 B757-200 L1011-1/100/200 B747-200/300 F28-4000/6000 BAE146-100/RJ70 BAE146-200 BAE-146-300 F100 RJ85 RJ200/ER EMB145 DHC8-300 D328 J41 BAE-ATP ATR72 DHC7 S360 B1900 J31 DHC8-100 SA226 SA227 EMB120 S340A ATR42 DC9-30 CV880 L1011-500 DC10-30 MD11 B747-100 Turboprops B707-300B bikian et al. (2002)Ba Regional Jets Large Aircraft 1955 1960 1965 1970 1975 1980 1985 1990 1995 2000 Year ? 2003 Waitz 50 EFFICIENCY Regional Jets Versus Turboprops 6 Energy Usage (MJ/ASK) 5 Regional BAC111-400 Jet Fleet Regional 4 CV880 Aircraft Fleet BAC111-200 CV600 3 RJ200/ERB1900 F28-1000 L188A-08/188C BAE146-100 RJ85 F28-4000/6000 F27 J31 DHC7 SA226 S360 SA227 BAE-146-300 F100 EMB145 2 J41 D328 Turboprop BAE146-200 DHC8-300 Fleet DHC8-100 ATR72 S340A Babikian et al. (2002) EMB120 1 ATR42 BAE-ATP Turboprops Regional Jets 0 1955 1960 1965 1970 1975 1980 1985 1990 1995 2000 2005 Year ? 2003 Waitz 51 ENERGY USAGE Total Versus Cruise 0 1 2 3 4 5 MJ/ASK E U,CR Large Aircraft Total E U Large Aircraft E U,CR Regional Aircraft Total E U Regional Aircraft Babikian (2001) 1955 1960 1965 1970 1975 1980 1985 1990 1995 2000 Year 52 ? 2003 Waitz COMMERCIAL AIRCRAFT ENERGY INTENSITY TRENDS ? New technology energy intensity has been reduced 60% over last 40 years (jet age) – 57% due to increases in engine efficiency – 22% due to increases aerodynamic performance – 17% due to load factor – 4% due to other (structures, flight time efficiency, etc.) – Structural efficiency constant (but traded for aero, passenger comfort, noise and SFC) – Flight time efficiency constant (balance of capacity constraints and improved ATM) ? Fleet average energy intensity has been reduced 60% since 1968 – Lags new technology by 10-15 years ? 2003 Waitz 53 SHORT HAUL AIRCRAFT Facing Increasing Scrutiny E U (MJ/ASK) 3.5 3.0 2.5 2.0 1.5 1.0 0.5 0 Jets Turboprops Aircraft introduced during or after 1980 only (Babikian, 2002) 0 1000 2000 3000 4000 5000 6000 7000 8000 9000 Stage Length (km) Royal Commission on the Environment (2002) the prospect of continuing rapid increases in air transport, particularly an increase in short haul flights…” government should divert resources...encouraging and facilitating a modal shift from air to high- “…deeply concerned at “It is essential that the speed rail.” ? 2003 Waitz 55 IMPACT OF NASA TECHNOLOGY SCENARIOS Global CO 2 Emitted per Year Billion Kg Effect of Proposed Environmental CO 2 Goals 2000 1750 1500 1250 1000 750 500 250 0 1990 2000 2010 2020 2030 2040 2050 No Improvement Beyond 1997 Technology 25% Reduction Introduced in 2007 50% Reduction Introduced in 2022 Zero CO2 Emission A/C Introduced in 2027 Zero CO2 Emission A/C Introduced in 2037 +340% +140% +230% +40% Change Relative to 1990: Emission inventories U.S. DOE reported fuel use 1990-5% Level -20% ( - GA and Military Emissions based on Boeing forecast - IPCC IS92a based ICAO demand model - No retrofit of technologies) Kyoto Protocol Timing For Reductions Year J. E. Rohde, NASA 1999 ? 2003 Waitz 56 IMPACTS OF MISSION REQUIREMENTS (NOx & Noise) ? Range/payload ~ fuel efficiency (commercial and military) High pressures and – Thermal efficiency temperatures High NO x – Propulsive efficiency velocity change Large mass flow with small Low Noise ? Maneuverability (military) High energy conversion per – High thrust-per-weight, unit volume (high small compact engine temperatures and pressures) High NO x ? Supersonic flight (military) velocity change – Low drag, small compact engine Small mass flow with large High Noise ? 2003 Waitz 57 NO x EMISSIONS TECHNOLOGY TRENDS ? 2003 Waitz 58 NO x EMISSIONS TRENDS ? 2003 Waitz 59 HISTORICAL FLEET CRUISE EMISSIONS PER PASSENGER PER KILOMETER 1.0 Relative Emission / P ass-km 0.5 0 1975 1980 1985 1990 1995 NO x CO 2 , H 2 O CO HC Year (DuBois, Boeing) ? 2003 Waitz 60 TECHNOLOGY AND EMISSIONS ? Improvements will not keep up with growth ? Aircraft typically have greater impact per unit of fuel burned ? “Solutions” for global climate will require unprecedented action (demand management/regulations, electric vehicles, contrail avoidance, etc.) ? Current understanding is that hydrogen makes problem worse ? High uncertainty relative to global impacts ? Engine efficiency improvements exacerbate NO x and contrails ? Significant improvements in structural efficiency, aero and operations are possible – Improvements in these areas do not exacerbate other problems ? 2003 Waitz 61 SUMMARY ? Broad range of environmental impacts from aircraft – Social costs of same order as industry profits – Currently not internalized – Current technology path and regulations not aligned with social costs ? Strong growth in demand ? Increasing public concern/regulatory stringency ? High uncertainty ? Many competing trades – Environmental impacts – Design, operations ? 2003 Waitz 62 SELECTED REFERENCES ? Babikian, R., Lukachko, S. P. and Waitz, I. A. "Historical Fuel Efficiency Characteristics of Regional Aircraft from Technological, Operational, and Cost Perspectives,” Journal of Air Transport Management, Volume 8, No. 6, pp. 389-400, Nov. 2002 ? Lee, J. J., Lukachko, S. P., Waitz, I. A., and Schafer, A., “Historical and Future Trends in Aircraft Performance, Cost and Emissions,” Annual Review of Energy and the Environment, Volume 26, 2001. (Available on Waitz web page) ? Waitz, I. A., Lukachko, S. P., and J. J. Lee, "Military Aviation and the Environment: Historical Trends and Comparison to Civil Aviation," AIAA-2003-2620, invited contribution to AIAA/ICAS International Air and Space Symposium and Exposition, Dayton, Ohio, July 14-17, 2003. ? Marks, D. H., et al., "Mobility 2001", World Business Council for Sustainable Development, Switzerland, 2001. (Available on Waitz web page) ? Miake-Lye, R.C., Waitz, I.A., Fahey, D.W., Kolb, C.E., Wesoky, H.L., and Wey, C.C., “Aviation and Climate Change,” Aerospace America, September, 2000. (Available on Waitz web page) ? Penner et al., United Nations Environment Programme, Intergovernmental Panel on Climate Change (IPCC), Special Report on Aviation and the Global Atmosphere, 1999. (Summary for Policy Makers available on Waitz web page) ? RCEP, “The Environmental Effects of Civil Aircraft In Flight,” Royal Commission on Environmental Pollution (RCEP), England, December, 2003 ? Waitz web page: http://web.mit.edu/aeroastro/www/people/iaw/bio.html ? 2003 Waitz 63