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ALAQS Trade-Off Feasibility Study and INM

import verification

EEC/SEE/2007/005

ALAQS - Trade-Off Feasibility Study and INM import verification This report was prepared for EUROCONTROL Experimental Centre ALAQS by: ENVISA Author(s): Nicolas Duchene, Ivan de Lepinay

ENVISA 38 rue des Gravilliers 75 003 PARIS [email protected] www.env-isa.com

Ian Fuller, EUROCONTROL Experimental Centre Review: ALAQS Peer Review Group. EEC Note : EEC/SEE/2007/005

© European Organisation for the Safety of Air Navigation EUROCONTROL 2007 This document is published by EUROCONTROL in the interest of the exchange of information. It may be copied in whole or in part providing that the copyright notice and disclaimer are included. The information contained in this document may not be modified without prior written permission from EUROCONTROL. EUROCONTROL makes no warranty, either implied or express, for the information contained in this document, neither does it assume any legal liability or responsibility for the accuracy, completeness or usefulness of this information.

ALAQS - Trade-Off Feasibility Study and INM import verification

EXECUTIVE SUMMARY

This report presents the outcome of a simple environmental trade-off study performed under contract ALAQS A03. The study evaluated the noise and emission impact of two different take-off / landing configurations at a medium-sized airport, using the ENHANCE / INM and ALAQS AV tools respectively. The study was carried out with aim of verifying the interoperability of those tools with a single set of operational data, as well as highlighting potential gaps in the trade-off methodology.

Results confirmed that data can be easily imported from INM into ALAQS AV and revealed the importance of specifying accurate meteorological time series data at the airport, notably when creating concentration maps. Recommendations are given for running advanced trade-off studies, including the use of real radar data or census data to be superimposed with noise and concentration contours.


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REPORT DOCUMENTATION PAGE

Reference: SEE Note No. EEC/SEE/2007/005

Security Classification: Unclassified

Originator: ENVISA 38 rue des Gravilliers 75003 PARIS - FR www.env-isa.com For Society, Environment, Economy Research Area

Originator (Corporate Author) Name/Location: EUROCONTROL Experimental Centre Centre de Bois des Bordes B.P.15 91222 BRETIGNY SUR ORGE CEDEX France Telephone: +33 1 69 88 75 00

Sponsor: EUROCONTROL EATM

Sponsor (Contract Authority) Name/Location: EUROCONTROL Agency Rue de la Fusée, 96 B –1130 BRUXELLES Telephone: +32 2 729 90 11

TITLE: ALAQS : Trade-Off Feasibility Study and INM import verification Authors : Nicolas Duchene, Ivan de Lepinay EEC Contact: Ian Fuller

Date Aug 07

Pages 30

Figures 11

Tables 6

Appendix 0

References 4

EATMP Task Specification -

Project ALAQS A03

Task No. Sponsor TRSA03PT/D7.2d

Period 2007

Distribution Statement: (a) Controlled by: EUROCONTROL Project Manager (b) Special Limitations: None © Copy to NTIS: YES / NO Descriptors (keywords): ALAQS, ENHANCE, INM, tradeoffs, trade-off, noise, emission, concentration

Abstract: This report presents the outcome of a simple environmental trade-off study performed under contract ALAQS A03. The study evaluated the noise and emission impact of two different take-off / landing configurations at a medium-sized airport, using the ENHANCE / INM and ALAQS AV tools respectively with the aim of verifying the interoperability of those tools with a single set of operational data, as well as highlighting potential gaps in the trade-off methodology.

Results confirmed that data can be easily imported from INM into ALAQS AV and revealed the importance of specifying accurate meteorological time series data at the airport, notably when creating concentration maps. Recommendations are given for running advanced trade-off studies, including the use of real radar data or census data to be superimposed with noise and concentration contours.


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EEC/SEE/2007/005 vii

TABLE OF CONTENTS

1 INTRODUCTION...................................................................................................1

1.1 Background ...............................................................................................................................1

1.2 Objectives of the Study .............................................................................................................2

1.3 Plan of the report.......................................................................................................................2

2 DEFINITION OF THE AIRPORT CASE STUDY...................................................3

2.1 Airport layout .............................................................................................................................3

2.2 Parameters Impacting Aircraft Noise and Emissions / Concentrations ....................................4

3 NOISE MODELLING.............................................................................................6

3.1 Aircraft Noise Modelling ............................................................................................................6

3.2 Noise Contours .........................................................................................................................6

3.3 Estimation of the Cost of Noise.................................................................................................7

4 LOCAL AIR QUALITY MODELLING....................................................................9

4.1 Airport Local Air Quality Modelling............................................................................................9

4.2 Emission Inventory Results.......................................................................................................9

4.3 LASAT Parameters .................................................................................................................10

4.4 Meteorology ............................................................................................................................10

5 COMMON REQUIREMENTS FOR NOISE / LAQ ..............................................11

5.1 Aircraft Tracks .........................................................................................................................11

5.2 Aircraft Profiles........................................................................................................................11

6 RESULTS AND DISCUSSION ...........................................................................14

6.1 Comparison of Noise and Concentration Maps ......................................................................14

6.2 Uncertainties and Error Quantification ....................................................................................15

7 CONCLUSIONS AND RECOMMENDATIONS...................................................17

8 REFERENCES....................................................................................................18


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LIST OF FIGURES

FIGURE 1: TRADE-OFF BETWEEN NOISE AND EMISSIONS ............................................................................. 1

FIGURE 2: CASE STUDY AIRPORT LAYOUT ....................................................................................................... 3

FIGURE 3: NORTH CONFIGURATION LDEN NOISE CONTOURS........................................................................ 6

FIGURE 4: SOUTH CONFIGURATION LDEN NOISE CONTOURS ........................................................................ 7

FIGURE 5: EXAMPLE OF AIRCRAFT TRACKS FROM INM IMPORTED IN ALAQS-AV (BLUE FOR DEPARTURE, RED FOR ARRIVAL) ................................................................................................... 11

FIGURE 6: CONTRIBUTION OF DIFFERENT EMISSION HEIGHTS TO THE NEAR-GROUND CONCENTRATION FOR A DEPARTING AIRCRAFT AT DIFFERENT DISTANCES ALONG THE START DIRECTION. DEPICTED IS THE RELATIVE CONTRIBUTION OF DIFFERENT HEIGHT SEGMENTS TO THE CLIMB-OUT PHASE (AFTER LIFT-OFF) TO THE NEAR GROUND CONCENTRATIONS (JANICKE CONSULTING, 2006 EXTENSION PROGRAMME OF FRANKFURT AIRPORT). ..................................................................................................................... 12

FIGURE 7: AIRCRAFT EMISSION BETWEEN 500-600M IN ALAQS-AV (NORTH CONFIGURATION)....... 13

FIGURE 8: AIRCRAFT EMISSION BETWEEN 500-600M IN ALAQS-AV (SOUTH CONFIGURATION) ....... 13

FIGURE 9: NOX CONCENTRATIONS FOR NORTH AND SOUTH CONFIGURATIONS (RESP. LEFT AND RIGHT).................................................................................................................................................... 14

FIGURE 10: LDEN NOISE CONTOURS (55-75 DBA) FOR NORTH AND SOUTH CONFIGURATIONS (RESP. LEFT AND RIGHT)................................................................................................................................ 14

FIGURE 11: AIRCRAFT EMISSIONS AT GROUND LEVEL IN ALAQS-AV (NORTH / SOUTH CONFIGURATION) ............................................................................................................................... 15

LIST OF TABLES

TABLE 1: PARAMETERS IMPACTING AIRCRAFT NOISE AND EMISSIONS .................................................. 4

TABLE 2: DESCRIPTION OF SIMPLE AND ADVANCED STUDIES USING ALAQS-AV AND INM............... 5

TABLE 3: NOISE CONTOUR AREAS (SQUARE KILOMETRES) ......................................................................... 7

TABLE 4: ALAQS-AV EMISSION INVENTORY PARAMETERS ......................................................................... 9

TABLE 5: AIRCRAFT EMISSION INVENTORY RESULTS................................................................................... 9

TABLE 6: LASAT DISPERSION MODEL PARAMETERS ................................................................................... 10


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ABBREVIATIONS

AIP Aeronautical Information Publication

ALAQS Airport Local Air Quality Studies

ALAQS-AV ALAQS-Arc View (EUROCONTROL tool)

CDA Continuous Descent Approach

ENHANCE European Harmonised Aircraft Noise Contour Modelling Environment (EEC)

INM Integrated Noise Model (FAA tool)

LAQ Local Air Quality

PNR Preferred Noise Route


EEC/SEE/2007/005 1

1 INTRODUCTION

1.1 Background

Increased concern about aviation environmental impacts at airports is becoming a major constraint to air transport growth. While implementing noise abatement procedures, other environmental concerns such as local air quality and green house gas emissions have often been neglected. As a consequence, it appeared important to investigate a harmonised way to calculate noise and emissions / concentrations at airports. The focus of this report is on noise and local air quality, however it is important to include climate change impact as well as the social and economic considerations are also of interest when dealing with trade-offs.

There are a number of cases for which the evaluation of trade-offs should take place at airports. Some of them are listed below:

� Continuous Descent Approach (CDA)

� Night restrictions

� Preferred Noise Routes (PNR)

� Mitigation scheme

� Preferred runway

� Approach with vertical guidance

� Concentration Vs dispersion

As shown in Figure 1, the costs vary in terms of noise and emissions of the various procedures above. Whilst the parameters shown in Figure 1 consider the emissions a mass of pollutant, the issue of air quality legislation requires the concentration at receptors be calculated and these are highly dependant on local conditions. Therefore the most sustainable solution for one airport might not be applicable for another airport.

Figure 1: Trade-off between noise and emissions


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Today, most trade-off studies insist on emissions rather than concentrations. However, in order to be able to evaluate the health effects of bad air quality, it is important to look at concentrations rather than total emissions. Concentrations are much more difficult to investigate than emissions, due to their variation with aircraft operations, airside and landside emission sources, as well as meteorological conditions. Nevertheless, EU legislation for NOx and NO2 requires that model concentrations be written in terms of annual average concentrations, putting the stress on the acute / chronic health effects of high NO2 concentrations. A different situation is encountered in the US where the total emissions of NOx are regulated.

1.2 Objectives of the Study

Obviously, the perception of aviation’s environmental impact is greater at airport locations, due to the proximity of people who are directly exposed to noise and air quality nuisances. In order to provide a better understanding of the interdependencies between noise and local air quality models, an interface was developed in the EUROCONTROL ALAQS (Airport Local Air Quality Studies) tool to import noise studies from an ENHANCE / INM (Integrated Noise Model) study.

The feasibility study presented in this report was conducted in a harmonised way between noise and local air quality. The objectives were as follow:

� Verify that ALAQS-AV could correctly import an INM study

� Identify technical issues linked to the interoperability of ALAQS-AV and INM

1.3 Plan of the report

The report’s structure is as follows:

� Definition of the airport case study

� Noise modelling

� Local air quality modelling

� Common requirements for noise and local air quality

� Results and discussion

� Conclusion and recommendations


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2 DEFINITION OF THE AIRPORT CASE STUDY

2.1 Airport layout

Figure 2: Case study airport layout

A simple trade-off study was set up with ENHANCE / INM and then imported into ALAQS-AV. A crossed runways airport was chosen for this case study, as shown in Figure 2. Only runways (11-29 and 15-33) were modelled in the noise and local air quality tools. For a complete study, it would be necessary to model other emission sources, such as the aircraft taxiing phase.

The traffic sample considered was monitored at the airport in September 2005. It consists of 352 aircraft, small commercial jets being the most represented (A319, A320, B737-300, B737-400, B737-500, Embraer 145) followed by turboprops (DHC-8-300).

Basically, the trade-off study set-up here evaluates two runway configurations for the airport depicted in Figure 2: North and South. The same aircraft traffic, profiles and tracks are used in INM and ALAQS-AV studies. The runway use corresponding to those two configurations are described below:

� North configuration: arrivals on runway 33 ; departures on runway 29

� South configuration: arrivals on runway 11 ; departures on runway 15

The objective is to identify the most environmentally-friendly configuration (if any) for days when the airport ATC has the choice between the two (calm weather conditions).


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2.2 Parameters Impacting Aircraft Noise and Emissions / Concentrations

Table 1: Parameters impacting aircraft noise and emissions

Remark / clarification Impact on noise

Impact on LAQ

Aircraft speed yes yes Aircraft altitude yes yes Engine thrust, power setting and age

Speed, weight, climb rate, configuration (flaps, undercarriage)

yes yes

Atmospheric conditions yes yes Turbulence Higher external forces mean higher engine power

and therefore higher noise and emissions yes yes

Aircraft frame yes no Aircraft slant distance Slant distance is the point to point distance between

the aircraft and the noise/emission measurement point (receptor)

yes no

Elevation angle Elevation angle is the angle between the aircraft-

receptor segment and horizontal ground yes no

It is worth noticing that in most cases, the same parameters impact both noise and emissions, in particular those related to aircraft movements, procedures and operating conditions. Based on the table above, it is possible to derive common parameters for the elaboration of a harmonised trade-off study on noise and emissions. In particular, the following items need a common definition:

� Aircraft profiles

� Aircraft tracks

� Aircraft / engine combinations

As a consequence, the ALAQS-INM import interface was designed with the objective of transforming the data from an ENHANCE / INM study into an ALAQS-AV format. However, a number of additional requirements are necessary to run a dispersion study, which could not be provided by INM and therefore had to be estimated. In particular, a movement table is necessary in ALAQS-AV, i.e. each aircraft movement must contain an arrival or a departure time. INM calculations are based on three periods of the day only (7am, 7pm and 11pm). Since ALAQS-AV calculations are based on hourly emissions and hourly 3d grids, a suitable assumption for ALAQS-INM was to consider that all movements from one period occurred during the same hour (i.e. all movements from the 7am period in INM occurred between 7am and 8am in ALAQS-AV).

Another solution would be to define a movement table with profiles, tracks and movement time prior to the trade-off evaluation, then run the INM study and finally import it into ALAQS-AV and link the INM data to the initial movement table. This would be particularly interesting for radar-based studies over a period of a day since it would allow variable meteo conditions to be considered (as opposed to the approach chosen here which is constant meteo over one hour). Such a movement table may be created by ENHANCE directly.

The two types of studies (simple and advanced) that could be run using both ALAQS-AV and INM are summarised in the next table:


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Table 2: Description of simple and advanced studies using ALAQS-AV and INM

Parameter Simple study Advanced study

Period of the study Not necessary to know which particular day was considered.

Specific day / week

Tracks Based on Aeronautical Information Publication.

Based on radar data. Each movement can have its own track.

Profiles ICAO standard A or B Based on radar data. Each movement can have its own profile.

ALAQS movement table

Grouped according to INM categories (day, evening, night)

Detailed movement table. Each aircraft has its own movement time.

Meteorology Constant over the hour modelled / "worst case" meteo conditions

Detailed METAR data monitored for the day of interest

Possible use General evaluation of trade-off studies. Feasibility studies.

Validation studies (comparison of measured / modelled values)

The feasibility study reported in this document belongs to the simple category.


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3 NOISE MODELLING

3.1 Aircraft Noise Modelling

The FAA’s Integrated Noise Model (INM) is a tool used worldwide for aircraft noise calculations around airports. The INM 6.1 version was chosen here as it is compatible with the version of ALAQS-AV used for the emission part.

ENHANCE is a tool developed by the EEC, initially to facilitate importing radar or simulator data into the INM. ENHANCE notably calculates the Corrected Net Thrust (CNT) per engine associated with each flight profile, using the aircraft performance data and algorithms available in the INM.

In this study, ENHANCE essentially has a data formatting role, since no radar data was used. It makes it possible to easily assign default standard (ICAO B) profiles to the AIP ground tracks on a flight-by-flight basis, and derives the day period of flights (day, evening or night) from their operational time.

Using default landing and take-off profiles is acceptable for the present trade-off study, for the objective is to compare two different runway configurations. For the same reason, International Standard Atmosphere (ISA) conditions were used for noise calculations.

Lden noise contours from 55 to 75 dB(A) were calculated, with a step of 5 dB(A) – in agreement with Directive 2002/49/EC.

3.2 Noise Contours

Hereunder are the two Lden noise contours for North and South configurations respectively:

55 dBA

60 dBA

65 dBA

70 dBA

75 dBA

Figure 3: North configuration Lden noise contours


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55 dBA

60 dBA

65 dBA

70 dBA

75 dBA

Figure 4: South configuration Lden noise contours

The corresponding noise contour areas in square kilometres are detailed hereafter:

Table 3: Noise contour areas (square kilometres)

Level (dBA) North South Delta 55.0 24.527 24.428 -0.40% 60.0 9.718 9.517 -2.07% 65.0 3.961 3.846 -2.90% 70.0 1.445 1.426 -1.31% 75.0 0.577 0.581 0.69%

As predicted, noise contour areas are very similar from one configuration to the other, since the same traffic with the same flight profile are used for both scenarios. Slight differences like those in 60 and 65 dB(A) noise contour areas are probably due to the asymmetry of the runway configuration.

3.3 Estimation of the Cost of Noise

For a single detailed airport case study, the following process should be followed when evaluating the noise cost:

� Set up the noise contours around the flight paths

� Identify the number of dwellings and people in each noise contour

� Identify the number of schools, hospitals, nurseries at each noise contour

� Evaluate the noise management cost (prevention, minimisation, mitigation and compensation)

� Evaluate the aircraft noise impact on house prices around the airport


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� Willingness to pay

� Etc.

However, when dealing with general procedures that could apply to a number of airports, the surface of the noise contours themselves can provide valuable information on the impact of a specific procedure. Moreover, the comparison of the surfaces of the noise contours resulting from various proposed procedures can also give good information. Monetary conversion is useful in the case of win-lose scenarios essentially (reducing noise increases emissions, and vice versa), as opposed to win-win scenarios.


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4 LOCAL AIR QUALITY MODELLING

4.1 Airport Local Air Quality Modelling

As mentioned previously in this report, the airport air quality was modelled using the ALAQS-AV emission inventory model combined with the LASAT dispersion model. The runways location, the aircraft tracks and profiles, as well as the movement table were all imported from the INM study using the ALAQS-INM import functionality. The import process took place without any particular problem. The following table summarises the parameters defined in ALAQS-AV to run the calculations:

Table 4: ALAQS-AV emission inventory parameters

Parameter ALAQS-AV

Version July 2007 Calculation type Movement table Number of movements 352 Simulation period 1 day (7am - 23pm)

Objects modelled Runway 11-29 Runway 15-33

Emission indices ICAO databank issue 15 Vertical profiles INM standard ICAO B Emissions cut-off altitude 3000 ft Horizontal tracks User defined Pollutants NOx Developed by EUROCONTROL

4.2 Emission Inventory Results

Results from the emissions inventory are presented in the table below. Note that the 7 - 8am time slot was extracted separately since it is the basis for the dispersion calculations rather than the full day. The total emissions calculated for both runway configurations are very similar for all pollutants, which was expected since the same aircraft traffic and operations were modelled in both cases.

Table 5: Aircraft emission inventory results

CO (kg) HC (kg) NOx (kg)

North configuration - all day 130.4 4.1 972.8

South configuration - all day 130.1 4.1 972.1

North configuration - 7am 90.8 3.0 717.1

South configuration - 7am 91.2 3.0 717.5


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4.3 LASAT Parameters

Table 6: LASAT dispersion model parameters

Parameter LASAT / ALAQS-AV

Version 3.0 Grid size 100m Particle emission rate 80 Meteorology Constant Period of simulation 1 hour (7 - 8 am) Number of movements 252 Method 3D grid source Terrain Flat Building effect No Aircraft wake effect No Calculation area 20 km x 20 km

Vertical intervals 32 intervals (20 of them below 150m)

Pollutant NOx NOx chemistry - Roughness length 0.5 Anemometer height 10m Boundary layer model version 2.1 LASAT default

Source dynamics "smooth and shift"

4.4 Meteorology

There are various ways of considering meteorology when dealing with a dispersion case study. Depending on the type of simulation and on the objectives of the study, different types of meteorology files can be the best fit. For example, one might want to focus on worst-case meteo conditions when evaluating the impact of a new procedure on the concentrations and therefore assume constant meteorological conditions over the simulation period (low wind speed, very stable atmosphere). On the contrary, the use of meteo data monitored at airports (e.g. METAR) is also possible if one wants to evaluate the concentrations in a more realistic way. METAR data is collected at most airports during the whole day with time intervals between one half-hour to one hour. It is possible to process METAR data so that it can be used in most dispersion models. Once again, the use of hourly meteorology or constant meteorology for the day depends on the objective of the study.

Considering the case study presented in this report, it was decided to use meteorological conditions that are likely to authorise movements for both runway configurations North and South, the objective being to use the same meteo conditions in both cases. Therefore, a wind direction from the West (270º) and a low wind speed were chosen. It was arbitrarily decided to model meteo conditions that are likely to give rise to the highest concentrations, i.e. a very stable atmosphere.


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5 COMMON REQUIREMENTS FOR NOISE / LAQ

5.1 Aircraft Tracks

Figure 5: Example of Aircraft tracks from INM imported in ALAQS-AV (blue for departure, red for arrival)

The tracks shown above were derived from the airport AIP (Aeronautical Information Publication) and imported in ALAQS-AV after their use in an INM study. As a consequence of their origin, those tracks are simple and clearly defined. This is not the case when radar is used. In such a case, it would be necessary to filter both profiles and tracks using ENHANCE prior to the INM study. In addition, thorough verification and validation of such data should be undertaken to ensure that the radar profiles are accurate enough to allow for reliable emission calculations.

5.2 Aircraft Profiles

Recent studies in air quality at airports focused on evaluating the contribution of aircraft emissions from various heights to the concentrations experienced at ground level. The objective was to provide a better understanding of the impact of aircraft emissions on ground concentrations as well as to identify the altitude up to which it is important to provide a detailed modelling of the aircraft and of its performance. The rest of this section highlights some key conclusions of those studies.

The impact of emissions on the concentration near the ground strongly decreases with increasing emission height. Figure 2 shows the contribution of different emission heights to the


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near-ground concentration for a departing aircraft at different distances along the start direction. Depicted is the relative contribution of different height segments of the climb-out phase (after lift-off) to the near-ground concentration. Emissions above 600m contribute less than 2% and even less when considering both takeoff (before lift-off) and climb-out emissions (Janicke Consulting, 2006).

In addition, it was shown in the course of the ALAQS project with Zurich airport that the difference in NO2 ground concentrations when considering aircraft emissions up to 915m instead of 304m is an increase of a maximum of 0.75 µg/m3. In addition, the marginal rise in pollution was limited to the area close to the runways where concentrations were already high - above 30 µg/m3 (EUROCONTROL, 2006).

Figure 6: Contribution of different emission heights to the near-ground concentration for a departing aircraft at different distances along the start direction. Depicted is the relative contribution of different height segments to the climb-out phase (after lift-off) to the near ground concentrations (Janicke Consulting, 2006 Extension programme of Frankfurt Airport).

From the analysis of the above graph, it is possible to conclude that emissions above a height of 600m contribute very little to ground concentrations (below 5% regardless of the distance from the emission points). The emissions for a height of 500-600m as calculated by ALAQS-AV are shown in Figure 7 and Figure 8 for the North and South configurations respectively. In both cases, the aircraft departures (in blue) are the same for all aircraft up to 600m. Differences start occurring between tracks after that height, therefore leading to the conclusion that for the case study airport chosen, the tracks only have a little impact on concentrations. A similar observation can be made for arrivals (in red) which are already on a straight line for approach at a height of 600m. The use of radar data to perform a trade-off analysis would probably be more realistic, providing good radar data can be obtained (ideally down to the ground level).

It should be noted that no re-circulation of the air down to the ground as an effect of atmospheric meteorology was considered in the LASPORT model that was used to obtain Figure 6.


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Figure 7: Aircraft emission between 500-600m in ALAQS-AV (NORTH configuration)

Figure 8: Aircraft emission between 500-600m in ALAQS-AV (SOUTH configuration)


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6 RESULTS AND DISCUSSION

6.1 Comparison of Noise and Concentration Maps

The concentrations maps obtained for the two configurations are shown in Figure 9 and the noise contours in Figure 10.

Figure 9: NOx concentrations for NORTH and SOUTH configurations (resp. left and right)

Figure 10: Lden noise contours (55-75 dBA) for NORTH and SOUTH configurations (resp. left and right)

It can be observed from the concentration maps that the two configurations lead to quite different concentration contours. While in the case of the North configuration it is possible to distinguish two areas (high concentration above and low concentration below), the south configuration leads to only one area with greater concentrations (in red and yellow on Figure 9). The analysis of the results for the noise calculations shows an inversion of the noise contours depending on the runway configuration, but in both cases, the contours have the same surface and shape, apart from slight differences due to the runway configuration’s asymmetry. This is not the case at all for the local air quality concentrations.

The explanation for the variation in concentration contours can be derived from the analysis of the location of ground emissions depicted in Figure 11. In the case of the South configuration, emissions from arrivals (on the left runway) and from departures (right runway) are at the same


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distance on the y axis. Since the wind direction applied was from the west, emissions from arrivals and departures are directly added to each other which lead to greater concentrations. On the contrary, in the case of the North configuration, emissions from departures are slightly above the arrival emissions on the y axis. Therefore the concentration contours are greater in surface but lower in concentrations than in the South configuration. However, the results obtained would differ for other meteo conditions. Therefore the choice of the meteorological conditions is also critical when evaluating noise / concentrations trade-offs.

This conclusion also highlights the importance of choosing the parameters to compare concentration results carefully. The dispersion calculations showed that in terms of the concentrations area, the North configuration has a greater impact on LAQ than the South configuration, but in terms of concentration peaks the South configuration has the worst impact. A suitable solution would be to decide on the concentration values that should be used to create concentration contours (similarly to what is done for noise) which would allow for meaningful comparisons of concentration maps. The comparison of the surfaces would then lead to meaningful results. However, this method is suitable for general analyses only. In the case of a detailed trade-off assessment for a specific airport, it would be necessary to plot population data to estimate the number of people impacted by various concentration levels.

Figure 11: Aircraft emissions at ground level in ALAQS-AV (NORTH / SOUTH configuration)

6.2 Uncertainties and Error Quantification

There are a number of uncertainties that are linked to air quality and noise calculations. For the air quality part, a distinction has to be made between the emission inventory and the dispersion process. The topics which are likely to contribute to uncertainties and errors are listed below:

Emission inventory uncertainties:

� Description of aircraft profiles, procedures and tracks (geographical and temporal location of the pollution)

� Emission factors for aircraft engine

Dispersion modelling uncertainties:

� Inherent to the type of dispersion: Lagrangian (particle transport) or Gaussian (plume)

� Description of aircraft plume dynamics (engine exhaust and wing vortices)

� Accuracy of meteorological data

Noise-related uncertainties

� Description of aircraft profiles, procedures and tracks


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� Noise-Power-Distance data for aircraft engine / airframe

� Atmospheric conditions


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7 CONCLUSIONS AND RECOMMENDATIONS

A trade-off feasibility study was conducted for a simplified airport using the ALAQS-AV and ENHANCE / INM tools. The case study concerned a crossed (secant) runway airport with 352 movements covering a mixture of regional and international traffic spanning 1 day for 7h to 23h. Two scenarios, a North configuration and South configuration, were defined to examine the impact on noise and emissions of two runway operating modes: The same traffic sample was applied in both cases. The profiles used for the study were the ICAO standard B, and the tracks originated from AIP documents.

The ALAQS-AV function to import INM data was verified for aircraft tracks, profiles and runway coordinates. An ALAQS-AV study was created from the INM study without any manual input. From the ALAQS-AV emission inventory results, a dispersion study was created using the LASAT software. Considering that the movements were grouped over the same hour, the meteorology data applied was constant and was chosen to allow for both North and South configuration operations to take place (i.e. low wind speed from the West direction, very stable atmosphere).

The comparison of the results of noise and local air quality led to quite different conclusions. While in the case of noise the contours had almost the same surfaces for the North and South configurations, the concentration maps were very different. The North configuration lead to two distinct concentration areas (one high, one low) as opposed to the South configuration which ended up in only one concentration area - smaller in surface but greater in concentrations. This was a direct consequence of the meteorological parameters applied in the course of the dispersion study. This result highlighted the importance of choosing carefully the parameters to compare for the analysis of concentration contours: peak concentrations, surface of specific pollution levels, hourly or daily average, hourly or daily maxima, etc. In addition, meteorology has a critical impact on the final concentrations and as such it should be defined according to the objectives of a trade-off study.

In the course of this feasibility study, two types of trade-off studies have been described when dealing with ALAQS-AV and INM interoperability: simple and advanced. The case study reported here belongs to the simple category. It would be interesting to evaluate the feasibility of running an advanced study. Such a study should focus on a limited number of aircraft for which detailed and accurate radar data is available (until the ground) so that reliable tracks and profiles could be derived in ENHANCE / INM and imported in ALAQS-AV. Moreover, this would make it possible to define the best meteorological conditions to be used for such trade-offs.


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8 REFERENCES

[Ref 1.] EUROCONTROL, 2006, ALAQS-AV User Manual

[Ref 2.] FAA, 1999, Integrated Noise Model (INM 6.0) User’s Guide

[Ref 3.] EUROCONTROL, 2006, Sensitivity analyses at Zurich airport in 2004, available online at http://www.eurocontrol.int/eec/gallery/content/public/documents/EEC_SEE_reports/EEC_SEE_2006_003.pdf

[Ref 4.] Janicke Consulting, 2006 Ausbau Flughafen Frankfur Main - Unterlagen zum Plantesstellungverfahren, Appendix B: Einfluss der Emissionshohe. / Frankfurt Airport Construction - Documents for Airport Masterplanning, Appendix B : Impact of aircraft emission altitude, available online at http://cmsbak1.fraport.de/ONLINE/planfeststellungUnterlagen07/Ordner%2060/003_G13_1.pdf

For more information about the EEC Society, Environment and Economy Research Area please contact: Ted Elliff SEE Research Area Manager, EUROCONTROL Experimental Centre BP15, Centre de Bois des Bordes 91222 BRETIGNY SUR ORGE CEDEX France Tel: +33 1 69 88 73 36 Fax: +33 1 69 88 72 11 E-Mail: [email protected] or visit : http://www.eurocontrol.int/

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