ERCD REPORT Air noise and NO x emissions for B departures at London Heathrow. D Rhodes C Walker* A Clough

Transcription

1 Environmental Research and Consultancy Department ERCD REPORT 0505 Air noise and NO x emissions for B departures at London Heathrow D Rhodes C Walker* A Clough * AEA Technology plc

2 Environmental Research and Consultancy Department ERCD REPORT 0505 Air noise and NO X emissions for B departures at London Heathrow D Rhodes C Walker* A Clough Summary This report highlights the relationships between air noise and NO x emissions for B operations at London Heathrow Airport. The results show that the relationship is highly complex, and is dependent on many factors. From the work undertaken, it is clear that a trade-off exists between noise and emissions, and significant reductions in noise contour area can be achieved. However, in the case of Heathrow, the potential noise benefits are offset by the impact of aircraft emissions on residential areas to the north of the airport. Local air quality is a significant issue at Heathrow and European legislation requires member states to meet stringent targets by As a consequence of these issues, the impact of increased noise or emissions resulting from operational changes to departure procedures at Heathrow must be considered very thoroughly in light of any benefits that may gained. April 2005 Page ii

3 This report has been produced by the CAA in accordance with the commercial offer detailed in a letter to BAA plc dated 12 July This report was jointly prepared by CAA and AEA Technology plc. Consequently, statements contained within this report do not necessarily reflect the views or policies of CAA or AEA Technology plc. CAA Copyright ISBN X Enquiries regarding the content of this publication should be addressed to: Environmental Research and Consultancy Department, Directorate of Airspace Policy, Civil Aviation Authority, CAA House, Kingsway, London, WC2B 6TE. April 2005 Page iii

4 Contents Glossary of Terms viii 1 Introduction 1 2 Assumptions and Approach 1 3 Air Noise Calculation Methodology 3 4 NO X Calculation Methodology NO X Emissions NO X Concentrations 4 5 Results Air Noise Footprints (SEL) Average Air Noise (Leq) NO X Emissions NO X Concentrations 14 6 Conclusions 21 References 23 Appendix A Trajectory Data 24 Appendix B Map of Departure Route and Receptor Points 30 April 2005 Page iv

5 Tables Table 1 Take-off weight and initial thrust settings 2 Table 2 Receptor Points 2 Table 3 Emission factors and fuel flow rates for a Rolls Royce 4 RB H-T Table 4 Change in Sound Exposure Level (db SEL) at receptor location 5 relative to Scenario 1c. Table 5 Change in Sound Exposure Level (db SEL) at receptor location 6 relative to Scenario 2c Table 6 Footprint area changes relative to Scenario 1c 7 Table 7 Population changes relative to Scenario 1c 7 Table 8 Footprint area changes relative to Scenario 2c 8 Table 9 Population changes relative to Scenario 2c 9 Table 10 Change in average summer day Leq relative to 2002 data 10 Table 11 Change in average summer day Leq relative to 2002 data 11 Table 12 Contribution to average summer day Leq by aircraft type 12 Table 13 Estimated NO X emissions from take-off and climb-out 13 Table 14 Absolute contribution relative to the LHR2 emissions monitor 14 Table 15 Increase in the contribution to ground-level annual mean NO X 15 concentration from B take-off and climb-out compared with scenario 1c Table 16 Increase in the contribution to ground-level annual mean NO X 16 concentration from B take-off and climb-out compared with scenario 2c Table 17 Total ground-level annual mean NO X concentrations (µg m -3 ) 17 Table 18 Increase in the total ground-level annual mean NO X concentration 18 compared with Scenario 1c Table 19 Increase in the total ground-level annual mean NO X concentration 19 compared with scenario 2c Table 20 Percentage contribution to total aircraft NO X emission in 2002 by 20 aircraft group Table 21 Breakdown of total NO X concentration by source (for 2002) 20 April 2005 Page v

6 Figures Figure 1 Differences in SEL at each receptor point relative to Scenario 1c 5 Figure 2 Differences in SEL at each receptor point relative to Scenario 2c 6 Figure 3 Change in area of SEL noise footprint relative to Scenario 1c 7 Figure 4 Change in area of SEL noise footprint relative to Scenario 2c 8 Figure 5 Change in average summer day Leq relative to Scenario 1c 10 Figure 6 Change in average summer day Leq relative to Scenario 2c 11 Figure 7 Contribution to average summer day Leq by aircraft type 12 Figure 8 Increase in the contribution to ground-level annual mean NO X 15 concentration from B take-off and climb-out compared with scenario 1c Figure 9 Increase in the contribution to ground-level annual mean NO x 16 concentration from B take-off and climb-out compared with scenario 2c Figure 10 Increase in the total ground-level annual mean NO x concentration 18 compared with Scenario 1c Figure 11 Increase in the total ground-level annual mean NO x concentration compared with Scenario 2c 19 April 2005 Page vi

7 Intentionally Blank April 2005 Page vii

8 Glossary of Terms aal agl amsl db dba EI F oo FDR Leq LTO mbar NO X SEL Above Airfield Above ground level Above mean sea level Decibel units describing relative changes of sound level. It is used in this report to represent changes measured on the dba scale. Used to denote the absolute level of noise measured on an A-weighted decibel scale. Emission factor (sometimes termed emission index ) Rated output of the engine (i.e. percentage of thrust) Flight data recorder Equivalent sound level of aircraft noise in dba, often called equivalent continuous sound level. Landing and take-off Unit of pressure, one thousandth of a bar equivalent to 100 pascals Term used to describe the sum of nitric oxide (NO), nitric dioxide (NO 2 ), and other oxides of nitrogen Sound exposure level generated by a single aircraft at the measurement point, measured in dba. This accounts for the duration of the sound as well at its intensity April 2005 Page viii

9 1 Introduction 1.1 This report describes the results of work undertaken by the Civil Aviation Authority s Environmental Research and Consultancy Department (ERCD) and AEA Technology plc in order to make comparisons between air noise and NO X emissions at London Heathrow Airport. 1.2 The aim of the study was to understand the relationships and whether any tradeoffs exist between the amount of air noise and associated NO X emissions for a particular aircraft at various take-off weights and thrust configurations. 1.3 In practical terms, the size of the study limited the number of aircraft types and corresponding take-off weight/thrust settings that could undergo noise and emissions modelling. Given the importance of determining the relationship between noise and emissions, it was decided to base the study on a single aircraft type, namely the Boeing This type accounts for a large number of movements at Heathrow, and due to its size and weight, produces significant air noise levels and NO X emissions. 1.4 For each B departure a 4-dimensional trajectory was calculated using manufacturer's supplied performance data (Ref 1). The position-time information was then used as an input to both the air noise and emissions modelling process. 2 Assumptions and Approach 2.1 Two take-off weight configurations were assumed, based on 95% and 100% of the s maximum structural weight limitation (396.9 metric tonnes) corresponding to and tonnes respectively. The former weight corresponds to the mean value reported during past noise assessments at London Heathrow Airport (Ref 2). 2.2 For the purpose of this study, Rolls Royce RB H-T engines were assumed, as these were one of the most common types 1 fitted to British Airways aircraft, the largest operator of B s at Heathrow in In terms of weather conditions, a surface temperature of 15 C, nil wind and a barometric pressure of mbar were assumed. 2.3 For each take-off weight configuration, three initial thrust settings were considered giving rise to six scenarios. Based on informal guidance provided by British Airways, the lowest possible take-off thrust setting was determined (given the runway length available and assumed weather conditions). This value is believed to be typical for many B operations, as lower take-off power settings extend engine lifetimes and reduce the cost of maintenance. 1 British Airways, Cathay Pacific, South African and Qantas B aircraft are fitted with the G, G-T, H and H-T variants of the RB engine. These variants have different maximum rated performance and changes are often made to satisfy operational requirements. Aircraft registration records show that the H-T variant was one of the most common in use at Heathrow in The H-T provides the greatest initial take-off power range, and hence was chosen as being the most suitable for investigating a possible relationship between noise and emissions. April 2005 Page 1

10 2.4 Two other thrust settings (100% rated thrust and the mid point between 100% and lowest possible take-off thrust) were also used. Weight and initial take-off thrust settings for each of the six scenarios modelled are summarised in Table 1. Table 1 Take-off weight and initial thrust settings Scenario % of max take-off weight % of take-off weight % of initial (take-off) thrust setting 1a. 100% t 100% 1b. 100% t 96% 1c. 100% t 92% 2a. 95% t 100% 2b. 95% t 93.5% 2c. 95% t 87% 2.5 For each scenario, a 4-dimensional trajectory was calculated using guidance set out in the proposed update to ECAC Document 29 (Ref 3). The methodology has been validated against FDR information for a number of different aircraft types including the Boeing The data identifies key points along the flight trajectory when thrust/profile changes occur, and the elapsed time (from start of roll) for the aircraft to reach each point to a height of 10,000 feet. This data can be found at Appendix A and the corresponding departure route flown is depicted as a magenta line on the map at Appendix B. 2.6 In addition to the production of standard graphical outputs to portray noise footprints and NO x emissions surrounding the airport, it was decided to calculate absolute levels at various receptor points near the airport, or beneath the departure flight path. This approach permits a more accurate comparison of the results for each scenario. Details of the receptor points are listed in Table 2, and their location is depicted on the map at Appendix B. Table 2 Receptor Points No Location. Eastings Northings Elevation amsl (m) Height agl (m) 1 LHR2 emissions monitor Poyle noise monitor Longford (river bridge) Aerodrome boundary Harmondsworth Church Harlington X Roads Datchet School Old Windsor (A308 Royal Gardens) April 2005 Page 2

11 3 Air Noise Calculation Methodology 3.1 The flight trajectory data in Appendix A was used as input to the noise modelling process. The CAA Aircraft Noise Model, ANCON version 2 (Ref 4 and 5) was used to estimate noise levels at the receptor locations listed in Table 2. In addition, single event noise exposure footprints for each weight/thrust departure scenario was generated. 3.2 Finally, Leq values were calculated for each of the receptor points to show the effect each configuration would have on average summer daytime noise levels hypothetically assuming all departures from Runway 27R/09L to be identical in terms of weight/thrust configuration. It should be noted that changes relating to B departures from other runways, or any B arrivals were considered in the Leq predictions. 4. NO X Calculation Methodology This can be described in two main sections namely Emissions (i.e. the quantity of NO X produced by a single aircraft departure event) and Concentrations (i.e. the annual concentration of NO X attributable to a particular type of aircraft at a given receptor point). 4.1 NO X Emissions For each scenario, the total quantity of NO x produced from the start of take-off roll until reaching a height of 1,000 metres aal was estimated. This part of the LTO cycle, from now on is referred to as take-off and climb-out, and comprises of three modes: take-off roll (start of roll to main wheels off) initial-climb (main wheels off to throttle back 2 ) climb-out (throttle back to 1000 m) The emissions (in kg) arising from a given mode of aircraft operation are given by the product of (i) the duration of the operation (seconds), (ii) the number of engines, (iii) the engine fuel flow rate at the appropriate thrust setting (kg of fuel per second) and (iv) the emission factor for the pollutant of interest (kg of pollutant per kg fuel) The emission factors (sometimes termed emission indices ) for aircraft engines vary from one engine type to another, and, for a given engine, depend on thrust setting Emission factors and fuel flow rates for a Rolls Royce RB H-T engine were obtained from the ICAO databank, which gives certification test results at four thrust settings (7%, 30%, 85% and 100%). The test-average emission indices are assumed to apply to in-service engines. 2 Assumed to occur at m (1,000 ft) April 2005 Page 3

12 Table 3 - Emission factors and fuel flow rates for a Rolls Royce RB H-T Thrust setting (% F oo ) Fuel Flow (kg s -1 ) NO x EI (g / kg fuel) Emission indices and fuel flow rates for other thrust settings were obtained by piecewise linear interpolation of the published data. For example, if the thrust lies between 85% and 100%, fuel flow rate and emission index are linearly interpolated between these two values. Similarly, if the thrust lies between 30% and 85%, the linear interpolation is carried out between these two values. This approach differs slightly from the ICAO (CAEP/6) methodology which had not been published at the time of 2002 emissions study. 4.2 NO X Concentrations This work draws upon work already undertaken for BAA (Ref 6). The BAA work gave total annual mean NO X concentrations for 2002, which have formed the baseline for comparison for this study This work has assessed only the contribution to NO x concentrations from B s departures. The contribution from non-aircraft sources, aircraft other than B s and B s for modes other than take-off and climb-out has been extracted directly from the BAA work (Ref 6) Air quality standards are set for NO 2 rather than NO X. However, this work stops short of calculating NO 2 concentrations, as its focus was the assessment of B departures, and the relationship between noise and NO X B s accounted for 23,298 departures at Heathrow in For each scenario, these have been substituted in the baseline with take-offs and climb-outs as specified for the weight and thrust configuration on a 1:1 basis and have been modelled using the same dispersion modelling techniques as used in work undertaken for BAA (Ref 6) The distribution of B take-offs and climb-outs on each runway is the same as for the work undertaken for BAA (Ref 6). However, it should be noted that this methodology is different to that for noise modelling, which only considered the B take-offs from runway 27R/09L. April 2005 Page 4

13 5 Results 5.1 Air Noise Footprints (SEL) Table 4 and Figure 1 show the relative differences in SEL experienced at each of the receptor points for the single take-off events at 100% take-off weight. Comparison is made against Scenario 1c, which has the lowest initial take-off power. A noise benefit is generally achieved at locations immediately beneath the flight path for the higher thrust scenarios. However, noise levels do increase with thrust at points immediately adjacent to the runway (e.g. Longford River Bridge and Harmondsworth Church). Table 4: Change in Sound Exposure Level (dba SEL) at receptor location relative to Scenario 1c. No. Location 1a 1b 1 LHR2 Emissions monitor Poyle noise monitor Longford (river bridge) Aerodrome boundary Harmondsworth church Harlington cross-roads Datchet school Old Windsor (A308 Royal Gardens) Figure 1: Differences in SEL at each receptor point relative to Scenario 1c 4 3 Scenario 1a Scenario 1b Relative Change (db SEL) LHR2 Emissions monitor Poyle noise monitor Longford (river bridge) Harmondsworth Aerodrome church boundary Harlington cross-roads Datchet School Old Windsor Royal Gardens -2-3 April 2005 Page 5

14 5.1.2 Table 5 and Figure 2 show the relative differences in SEL experienced at each of the receptor points for the single take-off events at 95% take-off weight. Comparison is made against Scenario 2c, which has the lowest initial take-off power. As with the 100% take-off weight configurations, a noise benefit is generally achieved at locations immediately beneath the flight path for the higher thrust scenarios. However, noise levels do increase with thrust at points immediately adjacent to the runway (e.g. Longford River Bridge and Harmondsworth Church). Table 5: Change in Sound Exposure Level (dba SEL) at receptor location relative to Scenario 2c No. Location 2a 2b 1 LHR2 Emissions monitor Poyle noise monitor Longford (river bridge) Aerodrome boundary Harmondsworth church Harlington cross-roads Datchet school Old Windsor (A308 Royal Gardens) Figure 2: Differences in SEL at each receptor point relative to Scenario 2c 8 6 Scenario 2a Scenario 2b Relative Change (db SEL) LHR2 Emissions monitor Poyle noise monitor Longford (river bridge) Aerodrome boundary Harmondsworth church Harlington cross-roads Datchet School Old Windsor Royal Gardens -4 April 2005 Page 6

15 5.1.3 Table 6 and Figure 3 show the changes in area of the SEL footprints associated with single take-off events at 100% take-off weight. Comparison is made against Scenario 1c, which has the lowest initial take-off power. This result shows that increased take-off thrust provides a consistent reduction in area. Table 6: Footprint area changes relative to Scenario 1c SEL contour 1a 1b >80 dba -1.7% -1.5% >85 dba -3.1% -2.2% >90 dba -4.6% -2.7% >95 dba -6.5% -4.0% >100 dba -3.4% -1.8% Figure 3: Change in area of SEL noise footprint relative to Scenario 1c Footprint (dba) 0% >80 >85 >90 >95 >100 Change in Area -1% -2% -3% -4% -5% -6% -7% Scenario 1a Scenario 1b Table 7 shows the relative change in population living within the SEL footprints associated with single take-off events at 100% take-off weight. Comparison is made against Scenario 1c, which has the lowest initial take-off power This clearly shows the effect of small noise level increases upon the densely populated areas immediately to the north of the airport (e.g. Harlington and Harmondsworth). Paradoxically, in some cases the size of the footprint decreases and the population within that footprint increases. This is caused by small changes to the shape of the footprint and variations in population density. April 2005 Page 7

16 Table 7: Population changes relative to Scenario 1c SEL contour 1a 1b 80 dba -12% -7% 85 dba +2% +1% 90 dba +14% +10% 95 dba +20% +6% 100 dba -11% -19% Table 8 and Figure 4 show the changes in area of the SEL footprints associated with single take-off events at 95% take-off weight. Comparison is made against Scenario 2c, which has the lowest initial take-off power. This result shows that increased take-off thrust provides a consistent reduction in area. Table 8: Footprint area changes relative to Scenario 2c SEL contour 2a 2b >80 dba -1.6% -1.3% >85 dba -3.8% -2.6% >90 dba -6.1% -4.1% >95 dba -10.4% -7.0% >100 dba -6.4% -5.0% Figure 4: Change in area of SEL noise footprint relative to Scenario 2c Footprint (dba) 0% >80 >85 >90 >95 >100 Change in Area -2% -4% -6% -8% -10% Scenario 2a Scenario 2b -12% April 2005 Page 8

17 5.1.7 Table 9 shows the relative change in population living within the SEL footprints associated with single take-off events at 95% take-off weight. Comparison is made against Scenario 2c, which has the lowest initial take-off power. In a similar way to the 100% take-off weight configurations, this result displays some increases in population with increasing take-off thrust for some of the contours. Again, this is due to the influence of the densely populated areas to the north of the airport. Table 9: Population changes relative to Scenario 2c SEL contour 2a 2b 80 dba -14% -8% 85 dba +6% +2% 90 dba +10% +13% 95 dba +23% +7% 100 dba +44% +25% 5.2 Average Air Noise (Leq) Table 10 and Figure 5 show the predicted changes in average summer day Leq values at each of the receptor points for the 100% take-off weight (Scenarios 1a and 1b), compared to Scenario 1c. In each case, all instances of B departures from Runway 27R/09L in the 2002 data have been substituted with departures conforming to the weight/thrust configuration of the scenario. The data shows that greatest noise benefits will occur immediately beneath the departure flight path (Aerodrome boundary and Poyle noise monitor). Small increases will occur at some of the residential areas to the north of the airport (Harmondsworth Church and Longford river bridge). Table 10: Change in average summer day Leq relative to Scenario 1c (based on 2002 movement data) No. Location 1a 1b 1 LHR2 Emissions monitor Poyle noise monitor Longford (river bridge) Aerodrome boundary Harmondsworth church Harlington cross-roads Datchet school Old Windsor (A308 Royal Gardens) April 2005 Page 9

18 Figure 5: Change in average summer day Leq relative to Scenario 1c (based on 2002 movement data 3 ) Relative Change (dba Leq) LHR2 emissions monitor Poyle noise monitor Longford (river bridge) Aerodrome boundary Harmondsworth Church Harlington cross-roads Datchet School Old Windsor Royal Gardens Scenario 1a Scenario 1b Table 11 and Figure 6 show the predicted changes in average summer day Leq values at each of the receptor points for the 95% take-off weight scenarios, compared to the values obtained from actual 2002 records (Ref 7). In each case, all instances of B departures from Runway 27R have been substituted with departures conforming to the weight/thrust configuration of the scenario. Table 11: Change in average summer day Leq relative to Scenario 2c (based on 2002 movement data 3 ) No. Location 2a 2b 1 LHR2 Emissions monitor Poyle noise monitor Longford (river bridge) Aerodrome boundary Harmondsworth church Harlington cross-roads Datchet school Old Windsor (A308 Royal Gardens) Based on hr summer daytime Leq data amended to exclude Concorde. April 2005 Page 10

19 Figure 6: Change in average summer day Leq relative to Scenario 2c (based on 2002 movement data 3 ) 0.6 Relative Change (dba Leq) LHR2 emissions monitor Poyle noise monitor Longford (river bridge) Aerodrome boundary Harmondsworth Church Harlington cross-roads Datchet School Old Windsor Royal Gardens Scenario 2a Scenario 2b Table 12 and Figure 7 show the contribution by aircraft type to overall noise energy at London Heathrow Airport over the period June-September Table 12: Contribution to average summer day Leq by aircraft type 3 No. Location B747 B747 B733 B777 EA32 Other -400 (other) types 1 LHR2 Emissions monitor 22% 3% 14% 7% 19% 35% 2 Poyle noise monitor 38% 4% 9% 7% 14% 28% 3 Longford (river bridge) 24% 2% 11% 9% 16% 38% 4 Aerodrome boundary 35% 5% 9% 7% 14% 30% 5 Harmondsworth church 19% 1% 12% 8% 23% 37% 6 Harlington cross-roads 25% 2% 14% 8% 20% 31% 7 Datchet school 44% 5% 9% 6% 13% 23% 8 Old Windsor (A308 Royal Gardens) 43% 3% 4% 10% 17% 23% 3 Based on hr summer daytime Leq data amended to exclude Concorde. April 2005 Page 11

20 Figure 7: Contribution to average summer day Leq by aircraft type Significance (%) 100% 90% 80% 70% 60% 50% 40% 30% 20% 10% 0% B747 (other) B777 B733 EA32 B Other types LHR2 Emissions monitor Poyle noise monitor Longford (river bridge) Aerodrome boundary Harmondsworth church Harlington cross-roads Datchet school Old Windsor (A308 Royal Gardens) April 2005 Page 12

21 5.3 NO X Emissions The total NO X emissions estimated for each scenario are shown in Table 13. Table 13: Estimated NO X emissions from take-off and climb-out Time (s) Thrust (% F oo ) Fuel (kg) NO x (kg) Scenario 1a Take-off roll Initial-climb Climb-out Total: Scenario 1b Take-off roll Initial-climb Climb-out Total: Scenario 1c Take-off roll Initial-climb Climb-out Total: Scenario 2a Take-off roll Initial-climb Climb-out Total: Scenario 2b Take-off roll Initial-climb Climb-out Total: Scenario 2c Take-off roll Initial-climb Climb-out Total: Compared with Scenario 1c, Scenarios 1a and 1b show a 6% and 3% increase in total NO X emissions respectively, and an 18% and 9% increase in ground-level (take-off roll) NO X emissions respectively. Ground-level emissions have a far greater impact on ground-level concentrations than do elevated emissions Compared with Scenario 2c, Scenarios 2a and 2b show a 12% and 6% increase in ground-level (take-off roll) NO X emissions respectively, and a 33% and 16% increase in ground-level NO X emissions respectively The benefits of shorter times in mode for the higher thrust scenarios are outweighed by the greater fuel flow rates and NO X emission factors. April 2005 Page 13

22 5.4 NO X Concentrations The absolute contribution to ground-level annual mean NO X concentration from B take-off and climb-out varies significantly from one location to another. Table 14 shows the absolute contribution for scenarios 1c and 2c relative to the LHR2 emissions monitor. Table 14: Absolute contribution relative to the LHR2 emissions monitor No. Location Eastings Northings 1c 2c 1 LHR2 emissions monitor % 100% 2 Poyle noise monitor % 3% 3 Longford (river bridge) % 15% 4 Aerodrome boundary % 10% 5 Harmondsworth Church % 10% 6 Harlington X Roads % 20% 7 Datchet School % 1% 8 Old Windsor (A308 Royal Gardens) % 1% For scenarios 1a and 1b, the increase in the contribution to ground-level annual mean NO X concentration from B take-off and climb-out compared with scenario 1c is shown in Table 15 and graphically in Figure 8. Table 16 and Figure 9 show the increase for scenarios 2a and 2b compared with scenario 2c Increases are shown relative to scenarios 1c and 2c, because, in terms of the amount of reduced thrust used, these scenarios more closely reflect the way B s are operated currently At LHR2, the contribution to ground-level annual mean NO X concentration from B take-off and climb-out is dominated by operations on runway 27R. Here, the increases in the contribution to ground-level annual mean NO x concentration in 1a and 1b compared with 1c, and in 2a and 2b compared with 2c, reflect the increases in ground-level emissions, with some additional increase due to the shortening of the take-off roll concentrating emissions near the monitor At the Poyle noise monitor, the changes in contribution reflect the increase in emissions compensated for by the shortening of the take-off roll shifting emissions away from the Poyle noise monitor in westerly operations At Longford (river bridge), the contribution to ground-level annual mean NO X concentration from take-off and climb-out decreases with increased thrust, this is due to the shortening of the take-off roll on runway 27R shifting emissions away from Longford (river bridge). The same is true at the Aerodrome boundary, but the effect is not so pronounced due to greater contribution from easterly operations here. April 2005 Page 14

23 Table 15: Increase in the contribution to ground-level annual mean NO X concentration from B take-off and climb-out compared with scenario 1c No. Location Eastings Northings 1a 1b 1 LHR2 emissions monitor % 11% 2 Poyle noise monitor % -1% 3 Longford (river bridge) % -9% 4 Aerodrome boundary % -5% 5 Harmondsworth Church % 5% 6 Harlington cross roads % 11% 7 Datchet School % 4% 8 Old Windsor (A308 Royal Gardens) % 7% Figure 8: Increase in the contribution to ground-level annual mean NO X concentration from B take-off and climb-out compared with scenario 1c 30% 25% 20% Scenario 1a Scenario 1b 15% 10% 5% 0% Poyle noise monitor Longford (river bridge) Aerodrome boundary -5% -10% LHR2 emissions monitor Harmondsworth Church Harlington cross-roads Datchet School Old Windsor Royal Gardens -15% -20% -25% At Harmondsworth Church, the changes in contribution reflect the increase in emissions being partially compensated by the shortening of the take-off roll shifting emissions away from Harmondsworth Church in westerly operations Like LHR2, the increases in contribution at Harlington Cross Roads reflect mainly the increases in emissions. April 2005 Page 15

24 Table 16: Increase in the contribution to ground-level annual mean NO X concentration from B take-off and climb-out compared with scenario 2c No. Location Eastings Northings 2a 2b 1 LHR2 emissions monitor % 21% 2 Poyle noise monitor % 1% 3 Longford (river bridge) % -19% 4 Aerodrome boundary % -4% 5 Harmondsworth Church % 8% 6 Harlington cross roads % 19% 7 Datchet School % 8% 8 Old Windsor (A308 Royal Gardens) % 13% Figure 9: Increase in the contribution to ground-level annual mean NO X concentration from B take-off and climb-out compared with scenario 2c 50% 40% Scenario 2a Scenario 2b 30% 20% 10% 0% -10% -20% LHR2 emissions monitor Poyle noise monitor Longford (river bridge) Aerodrome boundary Harmondsworth Church Harlington cross-roads Datchet School Old Windsor Royal Gardens -30% -40% Datchet School and Old Windsor show only a very small contribution from aircraft, and increases in contribution reflect the increase in emissions being partially compensated for by the shortening of the take-off roll shifting emissions to the east during westerly operations. April 2005 Page 16

25 Table 17 shows the total ground-level annual mean NO x concentrations for 2002 and for each scenario, with the assumption that all B take-offs and climbouts in the 2002 baseline are substituted on a 1:1 basis with take-offs and climb-outs as specified for the weight and thrust configuration. The contribution from other aircraft and B non take-off and climb-out modes, along with non-aircraft sources, are assumed to be unchanged from No account has been taken of the change in throughput this may cause. Table 17: Total ground-level annual mean NO X concentrations (µg m -3 ) No. Location Eastings Northings Baseline (2002) 1a 1b 1c 2a 2b 2c 1 LHR2 emissions monitor Poyle noise monitor Longford (river bridge) Aerodrome boundary Harmondsworth Church Harlington cross-roads Datchet School Old Windsor (A308 Royal Gardens) For Scenarios 1a and 1b, the increase in the total ground-level annual mean NO x concentration compared with Scenario 1c is shown in Table 18 and graphically in Figure 10. Table 19 and Figure 11 show the increase for Scenarios 2a and 2b compared with Scenario 2c Comparison of the total concentrations for each scenario reflect the changes due to the different operation of B s diluted by the contribution from other aircraft and non-aircraft sources, which remain unchanged from case to case Comparison of the scenarios with the baseline makes little sense because the baseline includes B with different engine fits and weight configurations. The baseline has been included only to establish normal concentration levels of NO X at each of the receptor points. Further, comparisons of Scenario 1a (b or c) with Scenario 2a (b or c) should not be made, as the weight configurations are different. April 2005 Page 17

26 Table 18: Increase in the total ground-level annual mean NO x concentration compared with Scenario 1c No. Location Eastings Northings 1a 1b 1 LHR2 emissions monitor % 1.2% 2 Poyle noise monitor % -0.0% 3 Longford (river bridge) % -0.5% 4 Aerodrome boundary % -0.1% 5 Harmondsworth Church % 0.2% 6 Harlington X Roads % 0.4% 7 Datchet School % 0.0% 8 Old Windsor (A308 Royal Gardens) % 0.0% Figure 10: Increase in the total ground-level annual mean NO X concentration compared with Scenario 1c 2.50% 2.00% 1.50% Scenario 1a Scenario 1b 1.00% 0.50% 0.00% -0.50% LHR2 emissions monitor Poyle noise monitor Longford (river bridge) Aerodrome boundary Harmondsworth Church Harlington cross-roads Datchet School Old Windsor Royal Gardens -1.00% -1.50% April 2005 Page 18

27 Table 19: Increase in the total ground-level annual mean NO X concentration compared with scenario 2c No. Location Eastings Northings 2a 2b 1 LHR2 emissions monitor % 1.8% 2 Poyle noise monitor % 0.0% 3 Longford (river bridge) % -0.8% 4 Aerodrome boundary % -0.1% 5 Harmondsworth Church % 0.2% 6 Harlington X Roads % 0.6% 7 Datchet School % 0.0% 8 Old Windsor (A308 Royal Gardens) % 0.1% Figure 11: Increase in the total ground-level annual mean NO X concentration compared with scenario 2c 4.00% Scenario 2a 3.00% Scenario 2b 2.00% 1.00% Longford (river bridge) Aerodrome boundary 0.00% -1.00% LHR2 emissions monitor Poyle noise monitor Harmondsworth Church Harlington cross-roads Datchet School Old Windsor Royal Gardens -2.00% April 2005 Page 19

28 Table 20 shows the percentage contribution to total aircraft NO X emission by aircraft group at London Heathrow Airport in After the B fleet, the next largest contributor to NO x emissions in 2002 are the B777s followed by the A320s. Table 20: Percentage contribution to total aircraft NO X emission in 2002 by aircraft group Aircraft Group NO x (% of total) A % A % A320 variants % A % A % B737 classic variants % B737 next generation variants % B % B747 other variants 2.53% B % B % B777 (all variants) 18.57% Others 22.58% Table 21: Breakdown of total NO X concentration by source (for 2002) Eastings Northings Aircraft Other airport sources Roads Background Total LHR2 emissions monitor Poyle noise monitor Longford (river bridge) Aerodrome boundary Harmondsworth Church Harlington cross roads Datchet School Old Windsor (A308 Royal Gardens) includes A319, A320 and A321 5 includes 200, 300, 400 and 500 series 6 includes 600, 700, 800 and 900 series 7 roads included in background April 2005 Page 20

29 6. Conclusions 6.1 The results clearly highlight some complex relationships between air noise and NO x emissions for B operations at London Heathrow Airport. B operations at London Heathrow are very significant as they account for over 30% of both air noise and NO X emissions produced by aircraft. 6.2 In the case of air noise, the results clearly show that there are significant overall benefits to be gained from using maximum thrust on take-off. With greater thrust, an aircraft will become airborne sooner and thereafter will climb away with greater vertical speed. These two factors both serve to reduce the area of the ground footprint and this should reduce the corresponding resident population within it. 6.3 With greater thrust, an aircraft will produce disproportionately more NO X (as can be seen in Table 3) and the fact that it becomes airborne sooner means that ground level emissions will be more concentrated. It is known that ground-level emissions have a far greater impact on ground-level concentrations than those emitted after take-off. Consequently, the results clearly show that there are significant benefits from using minimal take-off thrust and the benefits of shorter take-off times for the higher thrust scenarios are outweighed by the greater fuel flow rates and NO X emission factors. 6.4 The above theory is not universally true in practice, and there are instances where reduced take-off power results in less ground noise, and greater power results in lower emissions at some receptor points. One such case is the increase in air noise at receptor points to the north of the airport for the full power scenarios. However, in the majority of locations, the trends are well pronounced which gives rise to a dichotomy reduce the noise and increase the emissions or vice versa? 6.5 Figure 5 and Figure 6 show that a reduction in the region of 0.5 db in average summer daytime Leq levels could be achieved in some of the residential areas to the north of the airport if all B s were to use full power on take-off. Table 7 and Table 9 illustrate the significant reductions in residential population that can be achieved by using full power take-offs. Furthermore, if a uniform 0.5 db reduction of noise energy were to be assumed and applied to 2003 data, the resident population within the 57 db(a) contour would reduce by approximately 20,000. (2003 Heathrow data is used for this illustration, as it is not skewed by Concorde operations). 6.6 In terms of NO X, Figure 10 and Figure 11 show that such a change would correspond to an increase in annual NO X concentration of roughly 1% in the same residential areas. From Table 21 it can be seen that, beyond the airfield boundary aircraft are not the greatest contributor of NO X. Despite this, NO X emissions in many of these areas are already quite high due to road traffic, and it is questionable whether any increase would be acceptable. 6.7 There is no doubt that a trade-off exists between noise and emissions. For an airport located amongst residential areas where air quality is not an issue, significant noise reduction benefits can be achieved for a small reduction in air quality. However, many large airports also have local air quality issues, and this is particularly the case for London Heathrow. There is therefore, no obvious solution, and the benefits and disbenefits must be carefully considered before adopting any changes to operating procedures. April 2005 Page 21

30 6.8 It is not clear from this work whether similar results would exist for other aircraft types, particularly the A320, B733 and B777 fleets which are more numerous at Heathrow. Further work to identify whether any noise/no X trade-offs exist for these aircraft is recommended. April 2005 Page 22

31 References 1 "Proposal for Methodology for Computing Noise Contours Around Civil Airports", ECAC Document 29R (Draft V6.0) volume 2: Technical Guide Appendix G, 12 May Review of the Departure Noise Limits at Heathrow, Gatwick and Stansted Airports, Additional Study of Boeing 747 departures, CS Report 9539 Supplement, Prepared on behalf of the Department of Transport, Civil Aviation Authority, ECAC.CEAC Doc No. 29R (Draft v6.0), Proposal for Methodology for Computing Noise Contours Around Civil Airports, The CAA Aircraft Noise Contour Model: ANCON Version 1, DORA Report 9120, Civil Aviation Authority, November The UK Civil Aircraft Noise Contour Model ANCON: Improvements in Version 2, R&D Report 9842, Civil Aviation Authority, July Air Quality Modelling for Heathrow Airport 2002, Underwood B Y, Walker C T and Peirce M J. netcen/aeat/env/r/1694/ Issue 1, Noise Exposure Contours for Heathrow Airport 2002, ERCD Report 0301, Civil Aviation Authority, May April 2005 Page 23

32 Appendix A Trajectory Data A1. Scenario 1a Trajectory Data A1.1 B runway 27R departure - 100% MTOW and 100% initial thrust Time Distance Distance Eastings Northings Height Height Speed Speed Thrust (secs) (ft) (m) (m) (m) (ft) (m) (kts) (m/s) (%) April 2005 Appendix A Page 24

33 A2. Scenario 1b Trajectory Data A2.1 B runway 27R departure - 100% MTOW and 96% initial thrust Time Distance Distance Eastings Northings Height Height Speed Speed Thrust (secs) (ft) (m) (m) (m) (ft) (m) (kts) (m/s) (%) April 2005 Appendix A Page 25

34 A3. Scenario 1c Trajectory Data A3.1 B runway 27R departure - 100% MTOW and 92% initial thrust. Time Distance Distance Eastings Northings Height Height Speed Speed Thrust (secs) (ft) (m) (m) (m) (ft) (m) (kts) (m/s) (%) April 2005 Appendix A Page 26

35 A4. Scenario 2a Trajectory Data A4.1 B runway 27R departure - 95% MTOW and 100% initial thrust. Time Distance Distance Eastings Northings Height Height Speed Speed Thrust (secs) (ft) (m) (m) (m) (ft) (m) (kts) (m/s) (%) April 2005 Appendix A Page 27

36 A5. Scenario 2b Trajectory Data A5.1 B runway 27R departure - 95% MTOW and 93.5% initial thrust. Time Distance Distance Eastings Northings Height Height Speed Speed Thrust (secs) (ft) (m) (m) (m) (ft) (m) (kts) (m/s) (%) April 2005 Appendix A Page 28

37 A6. Scenario 2c Trajectory Data A6.1 B runway 27R departure - 95% MTOW and 87% initial thrust. Time Distance Distance Eastings Northings Height Height Speed Speed Thrust (secs) (ft) (m) (m) (m) (ft) (m) (kts) (m/s) (%) April 2005 Appendix A Page 29

38 Appendix B Map of Departure Route and Receptor Points Reproduced from Ordnance Survey digital map. Crown Copyright All rights reserved April 2005 Appendix B Page 30