Therefore, there is a gap in existing knowledge. The importance of airport facilities in determining the overall environmental result, and the likely extent of future growth is not well understood. Furthermore, there is concern about the lack of research effort that is directed towards arresting unsustainable development. This research addresses both these issues. Until now there has been no research to directly measure the relative significance of airport facilities upon the environmental impact associated with air transport growth.
Reference 1 (Andrew W. Brown and M.R. Pitt)
Sustainability:
Sustainability is an area increasing in importance for the construction industry in general. This being the case, it is reasonable to expect the contemporary facilities manager (FM) to possess a specific set of tools and knowledge concerning environmental efficient building design and operation.
Airport facilities are considered to be of prime importance here in due to the level of predicted aviation sector growth and the very public and political spotlight which is frequently placed upon the detrimental environmental impacts that are associated with airport growth and expansion.
Airport facilities:-
The contemporary airport is complex and the facilities required to support it are diverse, both in terms of differing levels of technical complexity and service provision. There are two main fronts of operation; aeronautical and non-aeronautical.
The identified problem:-
In general, the airport generates 50 per cent of its revenue from aeronautical operations and 50 per cent from non-aeronautical operations (ACI, 1998). Evidence suggests that airports compete with one another on the grounds of the facilities they offer to passengers and airlines (ACI-NA, 1998). Therefore, on an a priori basis it is reasonable to predict that airports will seek to improve the facilities they provide in order to maximise the revenue they generate from the expected increase in general air transport. This being the case, it is clear that there will be a cause and effect relationship between the general growth in aviation, the airport's facilities and the total environmental impact caused by an airport. There is a general perception that the environmental problems at airports are primarily caused by aeronautical activity or by
inappropriate infrastructure provisions (for example extensive car parking provision but limited public transport options).
-ACI (1998), Almost Half of Airport's Revenues are Non-aeronautical, Airports Council International, Geneva.
-ACI-NA (1998), Enforcement Policy Regarding Unfair Exclusionary Conduct in the Air Transportation Industry, Airports Council International, North America, Ref. OST-98-3713, Washington, WA.
The air transport sector has a number of known and well-quantified problems in relation to the
environmental impacts that are associated with its activity.
However, in general, only limited measures are available in connection with managing existing aeronautical facilities towards reducing the total environmental burden. Reducing the environmental burden associated with an airport's aeronautical activity remains largely dependent upon advances in aircraft technology which, of course, remains independent of the FM. However, the same situation does not apply in the case of managing the environmental burden associated with non- aeronautical facilities. These also have significant environmental impacts primarily in connection with energy consumption, pollution and waste.
Nevertheless, since it is typical for large well developed airports to generate approximately 50 per cent of total income from non-aeronautical facilities, it is predictable that airports will require a growing revenue earning property portfolio including terminal buildings with associated shopping areas and restaurants, airport hotels and office accommodation. The aeronautical facilities and the non-aeronautical facilities are, of course, interrelated, so that one group cannot be developed in total isolation from the other. This is logical as there is no benefit in providing for increased passenger numbers if the aeronautical facilities cannot supply the necessary capacity.
Facilitating growth at airports
First, the airport can improve its present facilities so that it can handle larger aircraft. There is a proposal to build Terminal 5, which is planned to cater for very large commercial transports (VLCT), for example, the Airbus A350 aircraft. This allows more passengers to pass through the airport facilities, thereby increasing revenue, without increasing the number of scheduled slots for flights arriving and departing. Consequently, in the main, the aeronautical facilities, such as runways, taxiways and ATM/CNS systems, do not require to be adjusted.
Sustainability
The design of sustainable facilities represents a complex problem and requires the examination of a wide range of variables across a wide range of construction disciplines. For facilities to be considered sustainable they must be capable of being supplied at a positive rate while ensuring that resource stocks are not compromised. Their delivery and subsequent operation must minimise the consumption of natural resources and must prevent pollution.
Smith et al. (1998) suggest that there are a number of practical attributes within the concept of sustainability that can be applied to projects in the built environment.
These are:
. environmental limits;
. demand management;
. environmental efficiency;
. welfare efficiency; and
. equity.
While all of these are important in the airport development case, we suggest that the FM needs to be primarily concerned with environmental efficiency. The EU define environmental efficiency as ``the achievement of the maximum benefit for each unit of resources and waste produced'' (EU, 1996). Achieving environmental efficiency may require a number of strategies ranging from reducing CO2, NOX, SO2 emissions, lowering annual energy costs, reducing resource depletion while increasing recycling, to preventing any loss of biodiversity and damaging effects on flora and fauna (Pullen, 1999; Morris and Therival, 1995; Smith et al., 1998). In practical terms, realising environmental efficiency from built facilities involves targeting the following five key areas:
(1) embodied energy;
(2) CO2, NOX and SO2 emissions;
(3) materials reuse and recycling;
(4) energy in use;
(5) natural resource depletion
Reference 2
Despite dramatic reductions over the years in the noise produced by individual aircraft, airport noise remains a critical public policy issue today. Moreover, given the expected increases in airline traffic and airport operations over the next decades, the noise issue will continue to be a source of dissension. While the expansion requires demolition of several hundred properties, it also reorients the airport's flight paths, so that a new set of households will be exposed to noise (see McMillen, 2004).
(McMillen, D., 2004. Airport expansions and property values: the case of Chicago O'Hare airport. Journal of Urban Economics 55, 627-640)
Reference 3
The long-term continuous growth of air transport demand and the consequent spatial expansion of many airports aiming to handle this demand safely, efficiently, and effectively, have also raised the question regarding the sustainable development of these airports. In many cases, the scope and content of such development, including the responsible actors have not been quite clear. In general, concept of sustainable airport development may imply either a permanent trade-off between the airport long-term direct and indirect overall benefits and costs of impacts, or only the reduction of the impacts, i.e. externalities. One important externality at all airports is local air pollution, which can be considered because of the nature of the impact, as an externality, and in terms of the available mitigating measures.
In general, the total air pollution in a given area is proportional to the number of polluting activities and the intensity of air pollution per activity. At airports, the number of activities is closely related to the volume of accommodated traffic, usually expressed as the number of passengers, ATM (Air Transport Movements), and freight shipments (1 ATM corresponds to either one arrival or one departure flight). In many cases, the passengers and freight shipments can be expressed by acommonunit - theWLU(Workload Unit) (1WLUis equivalent to 1 passenger or 100 kg of freight) [17]. The intensity of air pollution per activity depends on the quantity and type of the energy consumed to carry out the activity, and the characteristics of the applied technology. At airports, the air pollution activities can be those traffic-related activities in the airport airside and those in the airport landside area. In the former case, the air pollution of arriving and departing aircraft during the LTO (Landing and Take-Off) cycle is considered [27]. In the latter case, the air pollution generated by airport groundaccess systems, for both passengers and freight, is considered. In addition, the air pollution from movement of intra-airport vehicles, aircraft servicing at the apron/gate complex, the heating and lighting of the passenger and cargo terminals, and the administrative complexes is considered.
[17] Doganis R. The airport business. London, UK: Routledge; 1992.
[27] Janic M. The sustainability of air transportation: a quantitative analysis and assessment. Aldershot, UK: Ashgate Ltd Limited; 2007.
Some estimates indicate that the airports contribute about 5% of the total air pollution generated by the entire air transport system, i.e. about 30 million tons per year [1]. Since this amount certainly contributes to global warming and related climate change, many airports have already undertaken a range of measures to mitigate air pollution, being either under their direct or indirect control. The absolute objective is to reduce the airport-related air pollution overall.
The ultimate objective is to become ''carbon-neutral'' entities, without both constraining growth and imposing unnecessary air pollution charges. Some of these measures can be summarized as follows [1]:
_ Preventing access of the highly polluting aircraft;
_ Reducing aircraft fuel consumption during the LTO cycles and excluding use of APUs (Auxiliary Power Unit) while at the parking stands;
_ Reducing the overall number of vehicles accessing and operating at a given airport;
_ Encouraging use of low or zero emission vehicles within the airport area;
_ Stimulating use of alternative fuels;
_ Reducing energy consumption in all buildings;
_ Taking over the different schemes of charging externalities such as emission trading or taxation.
The above-mentioned measures are self-explanatory. This paper investigates the effect of introducing alternative fuels (Liquid Hydrogen - LH2) and a cryogenic aircraft fleet on the long-term mitigation of greenhouse gas emissions in the airside area of a large airport [28]. The effects of introducing Liquid Hydrogen (LH2) as an alternative fuel on the long-term reducing air pollution at a given airport.
[28] Janic M. The potential of liquid hydrogen for the future ''carbon-neutral air transport system''. Transportation Research D 2008;13(No. 8):428-35.
Fuels:
Conventional jet a fuel - kerosene
Conventional Jet A fuel - kerosene, which powers most of today's commercial jet aircraft, is a derivative of crude oil [38]. The most important characteristics of this jet fuel are the specific energy (MJ/kg) and the volumetric energy (MJ/dm3) content. In general, a given quantity of fuel with a higher specific energy enables an aircraft to carry more passengers and cargo over a given distance. In addition, this aircraft can cover longer distances while carrying the given passengers
and cargo. In addition, fuels with a higher volumetric content enable aircraft to fly on longer distances, and vice versa. The main greenhouse gases emitted by burning conventional jet A fuel are Carbon Monoxide (CO), Carbon-Dioxide (CO2), water vapour (H2O), Sulphur-Oxides (SOx), Nitrogen-Oxides (NOx), and particles. For the two most important, CO2 and H2O, the emission rates are constant, 3.18 g/g of Jet A fuel, and 1.26 g/g of Jet A fuel, respectively. The emission rates for the third important NOx mainly depend on the fuel burning temperature. For example, this rate is approximately about 0.015 g/g of Jet A fuel during the cruising phase of flight [26,27].
[26] IPCC. Aviation and the global atmosphere. Intergovernmental panel of climate change. Cambridge, UK: Cambridge University Press; 1999.
[27] Janic M. The sustainability of air transportation: a quantitative analysis and assessment. Aldershot, UK: Ashgate Ltd Limited; 2007.
[38] Wood HJ, Long GR, Morehouse DF. Long-term world oil supply scenarios: the future is neither as bleak or rosy as some asserts. Washington DC, USA: EIA- Energy Information Administration, http://www.eia.doe.gov; 2003.
Liquid Hydrogen (LH2)
Liquid Hydrogen (LH2) as an aviation fuel has been generally considered as an alternative long-term solution for the significant reduction of the direct emissions of greenhouse gases generated by the growing air traffic [25,28]. The main problem in manufacturing hydrogen is choosing a manufacturing method (raw materials (fuels) and processes), which does not emit CO2. The technologies and methods to produce hydrogen are already commercially available, but it is only used in a small niche market as a chemical substance and not as an energy commodity. Most
hydrogen is produced from chemically reformed natural gas. There are also many other methods of producing hydrogen [4]:
[10,25]. [28].
The main operational characteristics of Liquid Hydrogen relevant for its prospective use in commercial air transport are the high specific energy and the very low volume density. They imply that in an aircraft powered by Liquid Hydrogen, a relatively small amount in terms of the quantity (i.e., the energy content) and a relatively large space in terms of the volume will have to be provided. Liquid Hydrogen as an aviation fuel has obvious advantages in terms of reducing the emission of particular greenhouse gases compared with today's conventional Jet A fuel. Its
burning does not produce CO2 and SOx. However, an issue of concern is the increased emissions of NOx, which is however expected to be reduced by designing the appropriate combustion chambers in cryogenic jet engines. Table 1 gives some characteristic details about the characteristics of the conventional Jet A fuel and Liquid Hydrogen as aviation fuel.
As can be seen, in addition to the above-mentioned superiority in energy performance, hydrogen directly emits much less amounts of all greenhouse gases as compared with the emissions from conventional jet fuel, apart from H2O (about 2.6 times more). In general, hydrogen is considered as safe aviation fuel. Nevertheless, its main potential disadvantages are the explosive rate of 13-79% concentration in the air and the very low ignition energy (about only 0.02 mili joules). Hydrogen also mixes faster with air than the conventional jet fuel' vapour, and disperses rapidly through the air, in contrast to the conventional jet fuel, which pools on the ground. It burns with a nearly invisible, colourless and odourless flame, which is also an important safety concern [25,28]. Nevertheless, LH2 still remains to be considered as an alternative aviation fuel, which offers the potential for the long-term sustainable development of large airports, at least in terms of stabilizing the emissions of CO2 and NOx.
[25] IEA. Hydrogen production and storage: research & development priorities and gaps. Paris, France: International Energy Agency; 2006.
[28] Janic M. The potential of liquid hydrogen for the future ''carbon-neutral air transport system''. Transportation Research D 2008;13(No. 8):428-35.
[10] Chevron. Alternative jet fuels. Addendum 1 to aviation fuels technical reviews (FTR-3/A1). USA: Chevron Corporation; 2006.
[4] Bossel U, Eliasson B. Energy and the hydrogen economy, report ABB Switzerland Ltd. corporate research, Baden- Dattwil, Switzerland; 2003.
Reference 4
Reference 5
Economic:-
In recent years, national and local governments have often sought the development of airport infrastructure as part of wider economic development initiatives to stimulate employment opportunities and increase household income, as well as to generate more business opportunities. With these economic benefits, however, there are often negative local environmental effects such as aircraft noise nuisance, soil contamination, and air pollution. Here we look at some of the trade-offs between narrowly defined economic gains from airport investment and the wider social costs associated with their environmental impacts
Aircraft engine emissions
Differences in aircraft operations, engine types, emission rates and airport congestion are important in influencing the damage level of different pollutants. Givoni and Rietveld (2009), Morrell (2009), and others have, for example, looked at the implications of aircraft size on CO2. Aircraft operations also impact on local air pollution, at ground level during landings and take-offs. Since we focus only on the local and regional impacts of an airport operation, only the impacts of emissions from landings and take-offs and 30- minute cruise stages are evaluated in the later analysis.
The differences in the fundamental assumptions on the types of damage included, such as the effects on health, vegetation, materials, aquatic ecosystem, as well as on the climate change and the area considered (local, regional or global) also contribute to the differing results.
Aircraft engine emissions
Differences in aircraft operations, engine types, emission rates and airport congestion are important in influencing the damage level of different pollutants. Givoni and Rietveld (2009), Morrell (2009), and others have, for example, looked at the implications of aircraft size on CO2. Aircraft operations also impact on local air pollution, at ground level during landings and take-offs. Since we focus only on the local and regional impacts of an airport operation, only the impacts of emissions from landings and take-offs and 30- minute cruise stages are evaluated in the later analysis.
Reference 8
The historical relationship between economic growth and the growth of air transport has been strong (ICAO, 2002a). Aviation has experienced rapid expansion as the world economy has grown. Passenger traffic (expressed as revenue passenger-kilometres) has grown since 1960 at nearly 9% per year, 2.4 times the global average growth rate in gross domesticproduc t (GDP).
In Europe and the UK, forecasts for unconstrained air traffic grow th suggest that the number of passengers using airports could more than double over the next 20 years and almost treble by 2030 (CEC, 1994; DETR, 2000a; Grayling and Bishop, 2001).
This trend is unsustainable and must be reversed because of its impact on climate and the quality of life and health of European citizens (CEC, 1999).
The development of any airport gives rise to significant environmental impacts, including noise disturbance, emissions to air, water pollution and habitat destruction. Some impacts arise from the operation of the airport, others as a result of providing additional airport infrastructure. All have the potential to constrain future aviation growth.
The environmental sensitivity of an airport is dependent upon a number of factors, the most obvious of which is the number of people who can be disturbed by its operations, this being determined by the location of the airport relative to residential areas, its departure routes and the number and type of aircraft flown. Unfortunately the most popular airports with the travelling publicare often those closest to the major centres of population, with the result that it is these which in many respects are the most environmentally sensitive.
In a statistical study of complaints about aircraft operations at a major UK airport, Hume et al. (2001) found that the analysis of noise complaint data has been a relatively neglected subject in the literature. As expected, they found the number of complaints to be positively correlated with noise exposure, with twice the complaints per movement at 110-114 PNdB compared with 74-79 PNdB. Also confirmed was the expected relationship between time of day and number of complaints, with night flights being the subject of on average nearly five times the number of complaints as day/evening flights. Hume et al. suggest that airport planners and managers take note of the significance of the human circadian pattern in aircraft noise sensitivity in order to minimize community disturbance.
Airport capacity is thus a function of operational scale, management and environmental constraints. More particularly, it is a function of: the spatial capacity of on and off-site infrastructure (encompassing an array of engineered systems, from surface transport routes to jet fuel delivery); the management and intellectual skills used to deploy and enhance the productivity of that infrastructure; and the capacity and willingness of the airports natural and social environment to tolerate the consequences of that deployment. Put simply, the environmental capacity of an airport can be defined as and equated with the capacity of the receiving environment, both human and non-human, to tolerate the impacts of airport activity. Upham (2001a) has set out the theoretical aspects of environmental capacity in relation to aviation in more detail.
Aircraft noise
With respect to impacts in the locality of an airport, aircraft noise disturbance is probably the single most important issue affecting the operation and development of airports around the world, and hence their capacity. Aircraft noise is related to the frequency and noisiness of aircraft movements and the proximity of communities relative to the airport's arrival and departure routes. The control and monitoring of aircraft noise are issues that have received significant attention, and aircraft and engine manufacturers have made significant technological improvements over the years. However, the benefits of such actions have been offset by the growth in air travel such that today most of the world's major airports have operational constraints or capacity limits based upon aircraft noise. In many cases these relate either to restrictions upon the use of noisier aircraft, night curfews or operational limits based upon a noise budget or the extent of a noise exposure contour. It is common practice to model the current and future noise impact of air traffic and its growth, and from demographic information calculate the number of people who are or would be exposed to noise disturbance as the airport grows. This gives an indication of the potential noise sensitivity of a particular airport, although there are very significant social and cultural factors that affect the perception of what is nuisance (Moss et al., 1997). For example, it is likely that increasing affluence tends to bring less tolerance of environmental disturbance, such that levels of noise that are considered acceptable today may result in community opposition in the future. A critical issue for airport operators and governments alike is the need for more effective land use planning, to prevent more noise sensitive uses such as housing being built in noise sensitive areas around airports, thereby protecting future airport capacity.
However, land use planning is more often than not concerned with longer term issues. Shorter term noise mitigation measures can also be adopted, such as modifying air traffic control procedures. In this connection, Clarke (2001) has considered the potential benefits of automation in air trafficc ontrol for implementing noise abatement procedures during aircraft take-offs and approaches. Using simulations of flight approaches to JFK Airport, he shows that contraction of peak noise contours is theoretically attainable with automated assistance in flight sequencing and spacing.
Air quality
Air quality in the vicinity of an airport is determined by a number of factors. The major sources of pollution are ground transport, aircraft emissions and apron activities such as aircraft refuelling (Taylor, 1995). Over the next two decades, emissions per individual car are expected to fall significantly in many parts of the world. Near to airports where car traffic flows are staticor falling, growth of aviation means that aircraft will have greater relative importance with respect to local air quality than is currently the case.
In terms of human exposure, the importance of airport related emissions varies from one site to another depending upon the location of the airport relative to centres of human habitation. Although currently of most concern in the most technologically developed nations, it is clear that air quality limits will be regulated by regional, national and international legislation in an increasing number of countries in the future.
Third party risk Communities surrounding airports-and their politicians- are paying increasing attention to the risk of third party and direct fatalities arising from aircraft accidents. Accident rates tend to be higher along the approach and departure routes, where air traffic is concentrated. The growth in air traffic is offsetting the benefits of increasing safety, with the result that the risk of an air accident is increasing on a yearly basis (Caves, 1996). In the UK and in the Netherlands, risk contour modelling systems are used to predict areas of high risk in which it is considered 'unacceptable' for people to live and work (DETR, 1997). Continuing growth in traffic has the potential to increase the size of these zones. In consequence, further airport growth may be restricted or airports may be 'obliged' to purchase and demolish properties to remove people from the areas of highest risk. Again it can be anticipated that public awareness
and expectation will increase the priority given to dealing with third party risk in the future.
Biodiversity
Airports by their very nature cover large areas of land and create zones which are either hostile to wildlife (paved or built) or an ecological monoculture (such as mown grassland). The more distant areas surrounding airports can, however, often be of considerable ecological value, particularly if the airport is located in a green belt surrounding a major urban conurbation, as is
often the case. The ability of an airport to extend its boundaries or even build upon parts of its own land can be restricted by the value of the habitats threatened.
This problem is most acute in parts of Europe, where sites protected by national or international convention have often prevented or restricted airport development. Given the commitments made at the Rio Earth Summit to protect biodiversity, such constraints are likely to become more apparent in the future, even in less developed countries.
Community opposition to growth
While the benefits of the growth and development of an airport are spread over a large geographical area, the costs are borne by the residents of its neighbouring communities. Local community opposition can constrain growth and confound efforts to gain planning approval for further development. In addition to opposition arising from disturbance caused by aircraft
noise, other major issues raised in complaints to airports include local air quality (particularly the smell of aviation fuel), congestion and accidents on local roads and fear of air accidents (Thomas, 1995). It would seem reasonable to assume that if local people cannot see a
reason to tolerate the nuisance caused by airport operations, they are more likely to object to airport growth.
The key to managing local community opposition is to adopt a 'good neighbour' strategy which addresses the major issues of concern, in so far as this is possible while meeting commercial or economic objectives. It is important to provide information to local residents about what actions are being taken to resolve their perceived problems, to establish a system of public consultation, to set targets publicly for improvement and then implement transparent monitoring systems to
show that progress is being made. In addition to minimising the adverse effects, however, it is also important that airports develop strategies which seek to maximise the social and economic benefits of their continuing growth and target these towards areas of greatest need or areas worst affected by their operation.
Infrastructure and environmental capacity
The operational capacity of an airport is a function of many different factors, including: requisite airspace, number of runways, extent of taxiway and apron development, number and size of terminals and landside facilities and the ease of access. As stated, however, a number of environmental factors can also lead to constraints on growth and development, via community opposition or regulatory standards. Airport developers can invest substantially in new infrastructure (such as a terminal) but not have the environmental capacity (particularly the willingness to accept noise) to allow it to be put to full use. This has been the case at Amsterdam Schiphol and Düsseldorf airports. Long term planning, coupled with an analysis of the environmental implications of potential future developments and traffic growth, is the key to maximising the potential capacity of an airport site.
Conclusion is interesting
