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Noise metrics comparison and its use on urban zoning in airport surveys: A Brazilian case study
Journal of Air Transport Management 14 (2008) 304–307
Contents lists available at ScienceDirect
Journal of Air Transport Management journal homepage: www.elsevier.com/locate/jairtraman
Noise metrics comparison and its use on urban zoning in airport surveys: A Brazilian case study Te´o C. Revoredo, Jules G. Slama* Department of Mechanical Engineering/COPPE/UFRJ, Universidade Federal do Rio de Janeiro, C.P. 68503, Rio de Janeiro 21945-970, Brazil
a b s t r a c t Keywords: Airport noise control Balanced approach Noise metrics Sensitivity studies
This paper considers the environmental acoustics metrics conversion problem in relation to airport noise. In many countries, there is a need to change the metrics used in airport noise studies and to establish the relation between two different metrics, like day night sound level DNL, used in airport noise zoning and LAeq used in urban areas. Here we present a practical method for airport noise metrics conversion. We present the theoretical basis for a practical way to compare DNL and LAeq as well as case study examples. Ó 2008 Elsevier Ltd. All rights reserved.
1. Introduction
main issues when dealing with airport zoning is the impact of noise on surrounding areas, and how to quantify this in the formulation of noise control policies (Nogueira and Slama, 2005). Here we introduce a way of evaluating noise around airports that is both cost and time efficient. The integrated noise model (INM), software version 6.0c developed by the US Federal Aviation Administration (FAA) (1999) is used to determine a relationship between noise metrics, and to help in the prediction of noise annoyance near airports sites. Brazil offers a useful case study of its potential application. Globally, the legislation that regulates noise pollution, especially around airports, varies by country and even between locations within countries. We use Brazilian legislation regarding noise pollution control at airport as an example of some of the problems that may arise.
Noise is one of the major external effects associated with modern transport. It regularly emerges as one of the top three public concerns in surveys and, despite reductions in noise per vehicular movement due to suppression and better design, the problem of noise annoyance persists.1 Commercial air transport, because of the concentration of traffic around airports, has been a focal point of public concerns. This in spite of increasingly stringent measures regarding engine and aircraft noise, and the use of more socially conscious take-off and landing paths and flight timings around airports. In most countries there are legal requirements regarding the noise that is permitted around airports, and many have curfews, usually during the night hours, when flying is banned. Internationally, entities such as the European Union are introducing similar ideas of noise measurement and control across groups of nations.2 The general standards used internationally being agreed by the International Civil Aviation Organization.3 As in other countries, airport noise is an issue in Brazil, and defining optimal noise zones, however, is challenging. One of the
* Corresponding author. Tel.: þ55 2125627875; fax: þ55 2125628383. E-mail address: [email protected] (J.G. Slama). 1 The economic literature provides both evidence on the social effects of airport noise (Van Praag and Baarsma, 2005) and the impacts that it can have on local residential property values (Levesque, 1994; Nelson, 2004). 2 Directive 2002/49/CE du Parlement europe´en et du Conseil du 25 juin 2002 relative a` l’e´valuation et a` la gestion du bruit dans l’environnement. 3 These noise Standards and procedures are reflected in Annex 16 – Environmental Protection, Volume I – Aircraft Noise and the Environmental Technical Manual on these of Procedures in the Noise Certification of Aircraft (Doc 9501). 0969-6997/$ – see front matter Ó 2008 Elsevier Ltd. All rights reserved. doi:10.1016/j.jairtraman.2008.08.003
Aeronautical legislation – portaria 1141 DG5 that uses day night sound level (DNL) is used to define airport zoning; The Conselho Nacional de Meio Ambiente (National Council of Environment) (CONAMA) resolution, March 8th 1990, refers to the Associaça˜o Brasileira de Normas Te´cnicas (Brazilian Association of Technical Standards – ABNT) NBR10151 standard, that uses LAeq metric (equivalent continuous A-weighted sound pressure level) for noise surveys and in zoning (Slama et al., 2006). The differences between the two metrics, however, can be considerable (Quilliou et al., 2003). The DNL value is defined for a 24 h period while the LAeq may change values frequently during the same period, depending on the time of evaluation. It is thus not possible to establish a relationship between DNL and equivalent LAeq in the same day (Revoredo and Slama, 2005). Initially an evaluation period for LAeq is defined that can be compared with DNL. Because the noise environmental legislation
T.C. Revoredo, J.G. Slama / Journal of Air Transport Management 14 (2008) 304–307
based on LAeq takes into account two different periods, diurnal and nocturnal, a diurnal period corresponding to the LAeqD metric, beginning at 7 am and ending at 10 pm, is defined along with a nocturnal period beginning at 10 pm and ending at 7 pm the next day, corresponding to the LAeqN. A relationship between these metrics for noise levels at a given location can then be seen using, LAeq, the equivalent continuous A-weighted sound pressure level (dB) calculated for 24 h; LAeqD, LAeq calculated during the day (7 am to 22 pm); and LAeqN, LAeq calculated during the night (from 22 pm to 7 am). Fig. 1 shows the relationships between the noise levels calculated using DNL, LAeq, LAeqD and LAeqN for a location lateral to Recife’s airport and their evolution during the day. The LAEQ levels are calculated using the types of aircraft using the airport over the 24hour period. It can be seen that DNL levels alone do not represent the entire noise annoyance around the airport; there are periods of the night, for example, from 3 am to 5 am when no aircraft movement takes place and thus no noise is generated by the airport (other than possibly by ground activities). The relationship between DNL and LAeq levels near an airport also varies as a function of size of the area around the airport that is affected. Both DNL and LAeq levels depend on this while, in addition, LAeq, also depends on the time period and duration considered.
2 LAeqD
1 6 ¼ 10 log10 4 3600 15
2 1 6 LAeqN ¼ 10 log10 4 3600 9
The day night sound level (DNL), the LAeqD and the LAeqN may be expressed as a function of the instantaneous sound level, LA(t), as
2
0
1 6 B DNL ¼ 10 log10 @ 4 3600 24
þ
Z
Z
10 pm
LA ðtÞ 10
10
dt
7 am
31 7 am
10 10 pm
LA ðtÞþ10 10
7C dt 5A
(1)
Z
Z
3
10 pm
LA ðtÞ 10
10
7 am
7 dt 5
(2)
3 7 am
10 10 pm
LA ðtÞ 10
7 dt 5
(3)
where LA(t) is the instantaneous sound level. From this it is possible to relate DNL to LAeqD and LAeqN as
DNL ¼ 10 log10
LAeqD LAeqN 1 15 10 10 þ 90 10 10 24
(4)
If we consider LAeqN to be equal to LAeqD D, it is possible to establish a direct relationship between DNL and LAeqD
DNL ¼ 10 log10
LAeqD LAeqD D 1 15 10 10 þ 90 10 10 24
(5)
that leads to
DNL ¼ LAeqD þ 10 log10 2. Relationship between DNL and LAeqD
305
i D 1h 15 þ 90 10 10 24
(6)
Hence, if D ¼ 10 then DNL ¼ LAeqD an if D ¼ 0 then DNL ¼ LAeqD þ 6.4 dB. If only one type of aircraft using the airport is considered, a sound exposure level (SEL1) is generated, and the following may be considered:
SELD SELN LAeqD LAeqN LAeqD LAeqN
SEL1 þ 10 log10 ND SEL1 þ 10 log10 NN SELD 10 log10 ðTD Þ SELD 10 log10 ðTN Þ SEL1 þ 10 log10 ND 10 log10 ðTD Þ SEL1 þ 10 log10 NN 10 log10 ðTN Þ N T D ¼ 10 log10 D N NN TD D NN 15 ¼ 1010 ND 9 ¼ ¼ ¼ ¼ ¼ ¼
(7)
Hence
D ¼ 10 log10
ND TN TD NN
LAeqD LAeqN ¼ 10 log10
Fig. 1. Noise levels during the day at Recife Airport. Note: The data is for one day during the week with the highest number of aircraft operations in the busiest moth of 2004.
ND N 10 log10 N TD TN
(8)
where SEL1 is the sound exposure level generated by one touch and go (TGO) movement of an airport’s representative aircraft; SELD is the global sound exposure level on a receiver, generated by aircraft movements during daytime (15 h); SELN is the global sound exposure level on a receiver, generated by aircraft movements during night time (9 h); ND is the number of daytime aircraft movements; NN is the number of night aircraft movements; TD is the duration of the daytime period and TN is the duration of night period. The idea is to consider all aircraft movements as if they were from the same type of aircraft. Since sound exposure is additive, it is possible to use a mean value and that is done by ‘‘converting’’ the noise generated by the other aircrafts to a normalized format, based on the noise generated by the representative aircraft, because when it comes to noise, the number of aircraft movements alone does not mean anything, once every aircraft represents a different noise exposure. This way, the representative aircraft’s noise becomes the
306
T.C. Revoredo, J.G. Slama / Journal of Air Transport Management 14 (2008) 304–307
Table 1 Difference between DNL and LAeqD. NN/ND (%)
DNL LAeqD (dB)
10 20 30 40 50 100
1.0 2.7 4.0 4.9 5.7 8.4
‘‘unit’’ on which the others will be represented. From this, it is seen what matters is the number of aircraft movements per hour during the day and night periods. Finally we get
DNL ¼ LAeqD þ 10 log10
15 N 1 þ 10 N 24 ND
(9)
which leads to Table 1. What can be represented graphically as follows (Fig. 2): the relation will vary from one location to another in the vicinity of the airport due to aircraft trajectory dispersion. Fig. 3. Affected area noise levels at Congonhas Airport.
3. Using INM to compare metrics The INM is a tool developed by the US FAA that generates noise curves based on information about the airport in study such as temperature, runway identifiers and coordinates, type of aircraft that operates on the airport and number of movements. INM also calculates the affected area by a particular noise level and outputs other types of information. One practical way of evaluating equivalence between noise metrics at an airport is to use INM to generate a noise footprint for the particular airport and then compare the areas affected by different noise levels when using different metrics. Similar affected area means equivalent levels. The two metrics are equivalent if they have the same environmental impact in terms of the affected area.
AðDNL ¼ aÞ ¼ A LAeq ¼ b 0DNL ¼ azLAeq ¼ b
(10)
where A(DNL ¼ a) is the area of the footprint defined by DNL ¼ a and A(LAeq ¼ b) is the area of the footprint defined by LAeq ¼ b. As an example, Figs. 3 and 4 show the approximate noise levels equivalence between DNL and LAeqD (Tables 2and 3).
Fig. 2. The relationship between DNL and LAeqD.
Congonhas and Guarulhos airports are major facilities in Brazil. Both are situated in Sa˜o Paulo with Guarulhos having approximately 390 movements (5% at night) and Congonhas 600 movements (10% at night) during a week day. Guarulhos is the country’s busiest airport by passenger traffic and is located in the neighborhood of Cumbica, in the city of Guarulhos, 25 km from Sa˜o Paulo’s downtown. Major expansions to the airport are planned. Congonhas Airport is situated 8 km from the Sa˜o Paulo’s downtown in the Campo Belo district. In 2007, it was the busiest airport in Brazil in terms of aircraft movements and the second busiest in terms of passengers. The graphs show the large differences between DNL and LAeqD levels at the airports; at Congonhas Airport, DNL is about LAeqD þ 1 dB, a difference of 6 dB when compared to Guarulhos. 4. Airport zoning To establish a method of airport zoning compatible with urban zoning in the adjacent neighborhoods, LAeqD and LAeqN noise footprints are generated to replace the DNL curves because urban zoning standards refers to both the diurnal and nocturnal periods.
Fig. 4. Affected area noise levels for Guarulhos Airport.
T.C. Revoredo, J.G. Slama / Journal of Air Transport Management 14 (2008) 304–307
307
Table 2 Equivalence between DNL and LAeqD at Congonhas Airport. DNL
LAeqD
DNL
LAeqN
55 60 65 70 75
53 58 63 68 73
55 60 65 70 75
46 51 56 60 65
Table 3 Equivalence between DNL and LAeqD for Guarulhos Airport. DNL
LAeqD
DNL
LAeqN
55 60 65 70 75
49 54 59 64 69
55 60 65 70 75
49 54 58 64 68 Fig. 5. LAD and LAN compared to DNL zoning using INM generated noise footprints.
Using these curves, compatibility between airport and urban zoning is automatic with both referring to the same criterion (Table 4). Airport zoning is defined in terms of LAeqD and LAeqN. In the cases of Congonhas Airport
LAeqD ¼ DNL 0:5 dBðAÞ/LAeqN ¼ DNL 19:5 dBðAÞ/LAeqD LAeqN ¼ 19 dBðAÞ
These newly defined permissible areas coordinate with the urban zoning, leading to fewer potential conflicts between authorities and local populations, and to a more optimal development of both the city and airport. An example of this zoning is show in Fig. 5.
and for Recife Airport 5. Conclusions
LAeqD ¼ DNL 6:6 dBðAÞ/LAeqN ¼ DNL 6:3 dBðAÞ Taking 58 dB(A) and a mixed, predominantly residential area for Congonhas Airport one finds an LAeqD level of 57.5 dB(A) and LAeqN of 38.5 dB(A) suggesting that the diurnal condition LAeqD 55 dB(A) is not verified. In Recife Airport, a DNL level of 58 dB(A) corresponds to an LAeqD level of 51.4 dB(A) and an LAeqN of 51.7 dB(A). In this case the nocturnal condition LAeqD 50 dB(A) is not verified. Thus, the use of the condition DNL 58 dB(A) may lead to different conditions in different airports. Thus, one may generate permissible areas for each land use defined in Table 4. These areas can be represented by the complimentary of the union of both INM generated LAeqN and LAeqD noise footprints corresponding to each standard class
Class A : LAD > 70 dbðAÞWLAN > 60 dbðAÞ
Noise nuisance is a major and mounting problem for airports near large urban areas. To plan successfully it is important to have good interfaces between airport planning and residential planning and this means common bases of information. The paper presented a method for establishing relationships between two widely used noise metrics, DNL and LAeq, for evaluating annoyance. The need for reconciliation is because different metrics are often used on airport zoning and for areas around the facility. The case study of Brazil provides a basis for developing a more harmonious approach to airport planning whereby the various local stakeholders can discuss issues on a common footing. Acknowledgments
Class B : LAD > 65 dbðAÞWLAN > 55 dbðAÞ
The authors would like to thank CNPq and INFRAERO supporting this work.
Class C : LAD > 60 dbðAÞWLAN > 55 dbðAÞ References
Class D : LAD > 55 dbðAÞWLAN > 50 dbðAÞ Class E : LAD > 50 dbðAÞWLAN > 45 dbðAÞ Class F : LAD > 40 dbðAÞWLAN > 35 dbðAÞ
Table 4 NBR10151 areas and levels for urban zoning, in db(A). Area types
Day
Night
Class
Predominantly industrial areas Recreational mixed areas Commercial and administrative mixed areas Predominantly residential mixed areas Strictly urban residential, school or hospital areas Rural and farmland areas
70 65 60 55 50 40
60 55 55 50 45 35
A B C D E F
Federal Aviation Administration, 1999. Integrated Noise Model 6.0 User’s Guide Available from: www.faa.org. Levesque, T.J., 1994. Modelling the effects of airport noise on residential housing markets. Journal of Transport Economics and Policy 28, 199–210. Nelson, J.P., 2004. Meta-analysis of airport noise and hedonic property values: problems and prospects. Journal of Transport Economics and Policy 38, 1–28. Nogueira, R.C.C., Slama, J.G., 2005 Implementing the balanced approach for airport noise control in developing countries: the case of Brazil. In: Proceedings of the Internoise, Rio de Janeiro. Quilliou, T., Slama, J.G., Revoredo, T.C., 2003. Airport noise sensitivity studies. Anais do DINCON 1, 1–6. Revoredo, TC, Slama, JG., 2005. Metrics conversion in airport noise. In: Proceedings of the 18th International Congress of Mechanical Engineering, 1, pp. 1–4. Slama, J.G., Nogueira, R.C.C., Revoredo, T.C., Gama, A.P., Azevedo, C., Magina, R.F., Morais, L.R., 2006. Novos Resultados nos Estudos do Grupo de Estudos em Ruı´do Aeroportua´rio da COPPE. In: V Congresso Iberoamericano de Acu´stica, 1, pp. 20–28. Van Praag, B.M.S., Baarsma, B.A., 2005. Using happiness surveys to value intangibles: the case of airport noise. Economic Journal 115, 224–246.
Contents lists available at ScienceDirect
Journal of Air Transport Management journal homepage: www.elsevier.com/locate/jairtraman
Noise metrics comparison and its use on urban zoning in airport surveys: A Brazilian case study Te´o C. Revoredo, Jules G. Slama* Department of Mechanical Engineering/COPPE/UFRJ, Universidade Federal do Rio de Janeiro, C.P. 68503, Rio de Janeiro 21945-970, Brazil
a b s t r a c t Keywords: Airport noise control Balanced approach Noise metrics Sensitivity studies
This paper considers the environmental acoustics metrics conversion problem in relation to airport noise. In many countries, there is a need to change the metrics used in airport noise studies and to establish the relation between two different metrics, like day night sound level DNL, used in airport noise zoning and LAeq used in urban areas. Here we present a practical method for airport noise metrics conversion. We present the theoretical basis for a practical way to compare DNL and LAeq as well as case study examples. Ó 2008 Elsevier Ltd. All rights reserved.
1. Introduction
main issues when dealing with airport zoning is the impact of noise on surrounding areas, and how to quantify this in the formulation of noise control policies (Nogueira and Slama, 2005). Here we introduce a way of evaluating noise around airports that is both cost and time efficient. The integrated noise model (INM), software version 6.0c developed by the US Federal Aviation Administration (FAA) (1999) is used to determine a relationship between noise metrics, and to help in the prediction of noise annoyance near airports sites. Brazil offers a useful case study of its potential application. Globally, the legislation that regulates noise pollution, especially around airports, varies by country and even between locations within countries. We use Brazilian legislation regarding noise pollution control at airport as an example of some of the problems that may arise.
Noise is one of the major external effects associated with modern transport. It regularly emerges as one of the top three public concerns in surveys and, despite reductions in noise per vehicular movement due to suppression and better design, the problem of noise annoyance persists.1 Commercial air transport, because of the concentration of traffic around airports, has been a focal point of public concerns. This in spite of increasingly stringent measures regarding engine and aircraft noise, and the use of more socially conscious take-off and landing paths and flight timings around airports. In most countries there are legal requirements regarding the noise that is permitted around airports, and many have curfews, usually during the night hours, when flying is banned. Internationally, entities such as the European Union are introducing similar ideas of noise measurement and control across groups of nations.2 The general standards used internationally being agreed by the International Civil Aviation Organization.3 As in other countries, airport noise is an issue in Brazil, and defining optimal noise zones, however, is challenging. One of the
* Corresponding author. Tel.: þ55 2125627875; fax: þ55 2125628383. E-mail address: [email protected] (J.G. Slama). 1 The economic literature provides both evidence on the social effects of airport noise (Van Praag and Baarsma, 2005) and the impacts that it can have on local residential property values (Levesque, 1994; Nelson, 2004). 2 Directive 2002/49/CE du Parlement europe´en et du Conseil du 25 juin 2002 relative a` l’e´valuation et a` la gestion du bruit dans l’environnement. 3 These noise Standards and procedures are reflected in Annex 16 – Environmental Protection, Volume I – Aircraft Noise and the Environmental Technical Manual on these of Procedures in the Noise Certification of Aircraft (Doc 9501). 0969-6997/$ – see front matter Ó 2008 Elsevier Ltd. All rights reserved. doi:10.1016/j.jairtraman.2008.08.003
Aeronautical legislation – portaria 1141 DG5 that uses day night sound level (DNL) is used to define airport zoning; The Conselho Nacional de Meio Ambiente (National Council of Environment) (CONAMA) resolution, March 8th 1990, refers to the Associaça˜o Brasileira de Normas Te´cnicas (Brazilian Association of Technical Standards – ABNT) NBR10151 standard, that uses LAeq metric (equivalent continuous A-weighted sound pressure level) for noise surveys and in zoning (Slama et al., 2006). The differences between the two metrics, however, can be considerable (Quilliou et al., 2003). The DNL value is defined for a 24 h period while the LAeq may change values frequently during the same period, depending on the time of evaluation. It is thus not possible to establish a relationship between DNL and equivalent LAeq in the same day (Revoredo and Slama, 2005). Initially an evaluation period for LAeq is defined that can be compared with DNL. Because the noise environmental legislation
T.C. Revoredo, J.G. Slama / Journal of Air Transport Management 14 (2008) 304–307
based on LAeq takes into account two different periods, diurnal and nocturnal, a diurnal period corresponding to the LAeqD metric, beginning at 7 am and ending at 10 pm, is defined along with a nocturnal period beginning at 10 pm and ending at 7 pm the next day, corresponding to the LAeqN. A relationship between these metrics for noise levels at a given location can then be seen using, LAeq, the equivalent continuous A-weighted sound pressure level (dB) calculated for 24 h; LAeqD, LAeq calculated during the day (7 am to 22 pm); and LAeqN, LAeq calculated during the night (from 22 pm to 7 am). Fig. 1 shows the relationships between the noise levels calculated using DNL, LAeq, LAeqD and LAeqN for a location lateral to Recife’s airport and their evolution during the day. The LAEQ levels are calculated using the types of aircraft using the airport over the 24hour period. It can be seen that DNL levels alone do not represent the entire noise annoyance around the airport; there are periods of the night, for example, from 3 am to 5 am when no aircraft movement takes place and thus no noise is generated by the airport (other than possibly by ground activities). The relationship between DNL and LAeq levels near an airport also varies as a function of size of the area around the airport that is affected. Both DNL and LAeq levels depend on this while, in addition, LAeq, also depends on the time period and duration considered.
2 LAeqD
1 6 ¼ 10 log10 4 3600 15
2 1 6 LAeqN ¼ 10 log10 4 3600 9
The day night sound level (DNL), the LAeqD and the LAeqN may be expressed as a function of the instantaneous sound level, LA(t), as
2
0
1 6 B DNL ¼ 10 log10 @ 4 3600 24
þ
Z
Z
10 pm
LA ðtÞ 10
10
dt
7 am
31 7 am
10 10 pm
LA ðtÞþ10 10
7C dt 5A
(1)
Z
Z
3
10 pm
LA ðtÞ 10
10
7 am
7 dt 5
(2)
3 7 am
10 10 pm
LA ðtÞ 10
7 dt 5
(3)
where LA(t) is the instantaneous sound level. From this it is possible to relate DNL to LAeqD and LAeqN as
DNL ¼ 10 log10
LAeqD LAeqN 1 15 10 10 þ 90 10 10 24
(4)
If we consider LAeqN to be equal to LAeqD D, it is possible to establish a direct relationship between DNL and LAeqD
DNL ¼ 10 log10
LAeqD LAeqD D 1 15 10 10 þ 90 10 10 24
(5)
that leads to
DNL ¼ LAeqD þ 10 log10 2. Relationship between DNL and LAeqD
305
i D 1h 15 þ 90 10 10 24
(6)
Hence, if D ¼ 10 then DNL ¼ LAeqD an if D ¼ 0 then DNL ¼ LAeqD þ 6.4 dB. If only one type of aircraft using the airport is considered, a sound exposure level (SEL1) is generated, and the following may be considered:
SELD SELN LAeqD LAeqN LAeqD LAeqN
SEL1 þ 10 log10 ND SEL1 þ 10 log10 NN SELD 10 log10 ðTD Þ SELD 10 log10 ðTN Þ SEL1 þ 10 log10 ND 10 log10 ðTD Þ SEL1 þ 10 log10 NN 10 log10 ðTN Þ N T D ¼ 10 log10 D N NN TD D NN 15 ¼ 1010 ND 9 ¼ ¼ ¼ ¼ ¼ ¼
(7)
Hence
D ¼ 10 log10
ND TN TD NN
LAeqD LAeqN ¼ 10 log10
Fig. 1. Noise levels during the day at Recife Airport. Note: The data is for one day during the week with the highest number of aircraft operations in the busiest moth of 2004.
ND N 10 log10 N TD TN
(8)
where SEL1 is the sound exposure level generated by one touch and go (TGO) movement of an airport’s representative aircraft; SELD is the global sound exposure level on a receiver, generated by aircraft movements during daytime (15 h); SELN is the global sound exposure level on a receiver, generated by aircraft movements during night time (9 h); ND is the number of daytime aircraft movements; NN is the number of night aircraft movements; TD is the duration of the daytime period and TN is the duration of night period. The idea is to consider all aircraft movements as if they were from the same type of aircraft. Since sound exposure is additive, it is possible to use a mean value and that is done by ‘‘converting’’ the noise generated by the other aircrafts to a normalized format, based on the noise generated by the representative aircraft, because when it comes to noise, the number of aircraft movements alone does not mean anything, once every aircraft represents a different noise exposure. This way, the representative aircraft’s noise becomes the
306
T.C. Revoredo, J.G. Slama / Journal of Air Transport Management 14 (2008) 304–307
Table 1 Difference between DNL and LAeqD. NN/ND (%)
DNL LAeqD (dB)
10 20 30 40 50 100
1.0 2.7 4.0 4.9 5.7 8.4
‘‘unit’’ on which the others will be represented. From this, it is seen what matters is the number of aircraft movements per hour during the day and night periods. Finally we get
DNL ¼ LAeqD þ 10 log10
15 N 1 þ 10 N 24 ND
(9)
which leads to Table 1. What can be represented graphically as follows (Fig. 2): the relation will vary from one location to another in the vicinity of the airport due to aircraft trajectory dispersion. Fig. 3. Affected area noise levels at Congonhas Airport.
3. Using INM to compare metrics The INM is a tool developed by the US FAA that generates noise curves based on information about the airport in study such as temperature, runway identifiers and coordinates, type of aircraft that operates on the airport and number of movements. INM also calculates the affected area by a particular noise level and outputs other types of information. One practical way of evaluating equivalence between noise metrics at an airport is to use INM to generate a noise footprint for the particular airport and then compare the areas affected by different noise levels when using different metrics. Similar affected area means equivalent levels. The two metrics are equivalent if they have the same environmental impact in terms of the affected area.
AðDNL ¼ aÞ ¼ A LAeq ¼ b 0DNL ¼ azLAeq ¼ b
(10)
where A(DNL ¼ a) is the area of the footprint defined by DNL ¼ a and A(LAeq ¼ b) is the area of the footprint defined by LAeq ¼ b. As an example, Figs. 3 and 4 show the approximate noise levels equivalence between DNL and LAeqD (Tables 2and 3).
Fig. 2. The relationship between DNL and LAeqD.
Congonhas and Guarulhos airports are major facilities in Brazil. Both are situated in Sa˜o Paulo with Guarulhos having approximately 390 movements (5% at night) and Congonhas 600 movements (10% at night) during a week day. Guarulhos is the country’s busiest airport by passenger traffic and is located in the neighborhood of Cumbica, in the city of Guarulhos, 25 km from Sa˜o Paulo’s downtown. Major expansions to the airport are planned. Congonhas Airport is situated 8 km from the Sa˜o Paulo’s downtown in the Campo Belo district. In 2007, it was the busiest airport in Brazil in terms of aircraft movements and the second busiest in terms of passengers. The graphs show the large differences between DNL and LAeqD levels at the airports; at Congonhas Airport, DNL is about LAeqD þ 1 dB, a difference of 6 dB when compared to Guarulhos. 4. Airport zoning To establish a method of airport zoning compatible with urban zoning in the adjacent neighborhoods, LAeqD and LAeqN noise footprints are generated to replace the DNL curves because urban zoning standards refers to both the diurnal and nocturnal periods.
Fig. 4. Affected area noise levels for Guarulhos Airport.
T.C. Revoredo, J.G. Slama / Journal of Air Transport Management 14 (2008) 304–307
307
Table 2 Equivalence between DNL and LAeqD at Congonhas Airport. DNL
LAeqD
DNL
LAeqN
55 60 65 70 75
53 58 63 68 73
55 60 65 70 75
46 51 56 60 65
Table 3 Equivalence between DNL and LAeqD for Guarulhos Airport. DNL
LAeqD
DNL
LAeqN
55 60 65 70 75
49 54 59 64 69
55 60 65 70 75
49 54 58 64 68 Fig. 5. LAD and LAN compared to DNL zoning using INM generated noise footprints.
Using these curves, compatibility between airport and urban zoning is automatic with both referring to the same criterion (Table 4). Airport zoning is defined in terms of LAeqD and LAeqN. In the cases of Congonhas Airport
LAeqD ¼ DNL 0:5 dBðAÞ/LAeqN ¼ DNL 19:5 dBðAÞ/LAeqD LAeqN ¼ 19 dBðAÞ
These newly defined permissible areas coordinate with the urban zoning, leading to fewer potential conflicts between authorities and local populations, and to a more optimal development of both the city and airport. An example of this zoning is show in Fig. 5.
and for Recife Airport 5. Conclusions
LAeqD ¼ DNL 6:6 dBðAÞ/LAeqN ¼ DNL 6:3 dBðAÞ Taking 58 dB(A) and a mixed, predominantly residential area for Congonhas Airport one finds an LAeqD level of 57.5 dB(A) and LAeqN of 38.5 dB(A) suggesting that the diurnal condition LAeqD 55 dB(A) is not verified. In Recife Airport, a DNL level of 58 dB(A) corresponds to an LAeqD level of 51.4 dB(A) and an LAeqN of 51.7 dB(A). In this case the nocturnal condition LAeqD 50 dB(A) is not verified. Thus, the use of the condition DNL 58 dB(A) may lead to different conditions in different airports. Thus, one may generate permissible areas for each land use defined in Table 4. These areas can be represented by the complimentary of the union of both INM generated LAeqN and LAeqD noise footprints corresponding to each standard class
Class A : LAD > 70 dbðAÞWLAN > 60 dbðAÞ
Noise nuisance is a major and mounting problem for airports near large urban areas. To plan successfully it is important to have good interfaces between airport planning and residential planning and this means common bases of information. The paper presented a method for establishing relationships between two widely used noise metrics, DNL and LAeq, for evaluating annoyance. The need for reconciliation is because different metrics are often used on airport zoning and for areas around the facility. The case study of Brazil provides a basis for developing a more harmonious approach to airport planning whereby the various local stakeholders can discuss issues on a common footing. Acknowledgments
Class B : LAD > 65 dbðAÞWLAN > 55 dbðAÞ
The authors would like to thank CNPq and INFRAERO supporting this work.
Class C : LAD > 60 dbðAÞWLAN > 55 dbðAÞ References
Class D : LAD > 55 dbðAÞWLAN > 50 dbðAÞ Class E : LAD > 50 dbðAÞWLAN > 45 dbðAÞ Class F : LAD > 40 dbðAÞWLAN > 35 dbðAÞ
Table 4 NBR10151 areas and levels for urban zoning, in db(A). Area types
Day
Night
Class
Predominantly industrial areas Recreational mixed areas Commercial and administrative mixed areas Predominantly residential mixed areas Strictly urban residential, school or hospital areas Rural and farmland areas
70 65 60 55 50 40
60 55 55 50 45 35
A B C D E F
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