Airports and Airlines are Taking a Variety of Actions to Reduce Emissions, Although Specific Impact of These Actions Unknown

Many of the nation’s busiest airports and airlines that serve them have  initiated voluntary emission reduction measures, such as converting  shuttle buses and other vehicles from diesel or gasoline fuels to cleaner  alternative fuels. While the actual impact of these measures is unknown,  some measures (such as shifting to new cleaner gas or diesel engines or  alternative fuels) have the potential to significantly reduce emissions, such  as nitrogen oxides, volatile organic compounds, particulate matter, and  carbon monoxide. Representatives from the aviation industry as well as federal and state  officials told us that the new air quality standards, combined with the  boost in emissions expected from increases in air travel, could cause  airports to be subject to more emission control requirements in the future. For example, a number of carriers at  Dallas/Fort Worth International and Houston airports have agreed to  voluntarily reduce emissions associated with ground service equipment by  up to 75 percent. Proposed Airport Projects Have Been Able to Conform to Current Air Quality Standards

In addition to facing control measures as part of state strategies to attain  the Clean Air Act’s ambient air quality standards, airports must also submit  most major construction project proposals for federal environmental  review, which includes an evaluation of the proposed project’s impacts on  air quality. The airport operators also indicated that having such a  program encourages airport sponsors to undertake efforts to reduce  emissions. However, the group has not defined specific objectives or established time  frames for achieving its goal of reducing aviation-related emissions. Two Countries Have Introduced Emission- Based Fees

Other countries use many of the same measures to reduce emissions at  airports as the United States and, in addition, two countries have imposed  landing fees based on the amount of nitrogen oxides emissions produced  by aircraft. Improvements in Aircraft and Engine Design Have Reduced Many Aircraft Emissions, but Nitrogen Oxides Emissions are Increasing

Although research and development efforts by NASA and aircraft and  engine manufacturers have led to engine and airframe improvements that  have increased fuel efficiency and lowered carbon dioxide and  hydrocarbon emissions, trade-offs among several factors, including engine  performance, have also resulted in increased nitrogen oxides emissions. Our analysis of data on aircraft emissions during landings and takeoffs  indicates that the newest generation of aircraft engines, while meeting  international standards, can produce considerably more nitrogen oxides  emissions than the older versions they are replacing. Our analysis of aircraft landing/takeoff emissions shows that newer  aircraft produce considerably more nitrogen oxides than older models. This TALON technology is being used on some aircraft in the U.S. In addition, more attention will be  focused on finding additional ways to reduce emissions from airports to  enable localities to meet more stringent ozone standards, which go into  effect in late 2003. Among the issues that the framework should address  are  the need for baseline information on the extent and impact of aviation- related emissions, particularly nitrogen oxides emissions;  the interrelationship among emissions and between emissions and noise;    options for reducing aviation-related emissions, including the feasibility,  cost, and emission reducing potential of these options;    goals and time frames for achieving any needed emission reductions;  the roles of NASA, other government agencies, and the aviation industry in  developing and implementing programs for achieving needed emission  reductions; and    coordination of emission reduction proposals with members of ICAO. A study of emissions at Los Angeles  International Airport is expected to shed some light on the subject. State environmental officials attribute this projected  increase in the airports’ ozone contribution to an expected doubling of  aircraft emissions coupled with a 50 percent decrease in emissions from  other sources. These air travel delays add to regional air quality problems  because idling aircraft contribute to pollution.
Why GAO Did This Study

Although noise has long been a problem around airports, the anticipated growth in demand for air travel has also raised questions about the effect of airport operations on air quality. Aviation-related emissions of nitrogen oxides, which contribute to the formation of ozone, have been of particular concern to many airport operators. A federal study at 19 airports estimated that, by 2010, aircraft emissions have the potential to significantly contribute to air pollution in the areas around these airports. GAO agreed to review efforts in the United States and other countries to reduce emissions at airports and the effect of improvements in aircraft and engine design on emissions.

What GAO Found

Many airports have taken measures to reduce emissions, such as converting airport ground vehicles from diesel or gasoline to cleaner alternative fuels. While the actual impact of these measures is unknown, some measures (such as shifting to cleaner alternative fuels) have the potential to significantly reduce emissions, such as nitrogen oxides. In some cases--such as at Los Angeles and Dallas/Fort Worth airports--the emission reduction measures have been imposed by federal or state agencies to bring severely polluted areas into attainment with the Clean Air Act's air quality standards or to offset expected increases in emissions from airport expansion projects. Many industry and government officials that GAO contacted said that new, stricter federal air quality standards that will go into effect in 2003, combined with a boost in emissions due to an expected increase in air travel, could cause airports to be subject to more federal emission control requirements. In 1998, a group of government and industry stakeholders was established to develop a voluntary nationwide program to reduce aviation-related emissions; however, thus far, the group has not agreed to specific objectives or elements of a program. Other countries use many of the same measures as the United States to reduce emissions at airports. Two countries have imposed landing fees based on the amount of emissions produced by aircraft. However, U.S. officials question the effectiveness of these fees. Research and development efforts by the federal government and the aircraft industry have improved fuel efficiency and reduced many emissions from aircraft, including hydrocarbons and carbon monoxide, but have increased emissions of nitrogen oxides, which are a precursor to ozone formation. As a result, many new aircraft are emitting more nitrogen oxides than the older aircraft they are replacing. For example, GAO's analysis of aircraft emission data shows that the engines employed on the newest models of a widely used jet aircraft, while meeting current standards for nitrogen oxide emissions, average over 40 percent more nitrogen oxides during landings and takeoffs than the engines used on the older models. Technologies are available to limit nitrogen oxide emissions from some other newer aircraft models. Many state and federal officials GAO contacted said that, in the long term, nitrogen oxide emissions from aircraft will need to be reduced as part of broader emission reduction efforts in order for some areas to meet federal ozone standards.