ON NOISE MAPPING AND ACTION PLANS IN PORTUGAL

Transcription

1 23 rd International Congress on Sound & Vibration Athens, Greece 0- July 206 ICSV23 ON NOISE MAPPING AND ACTION PLANS IN PORTUGAL José Luis Bento Coelho and Diogo Alarcão Group of Acoustics and Noise Control, Instituto Superior Técnico, University of Lisboa, Portugal Experience on noise mapping and action plans of agglomerations and transport infrastructures in recent years in Portugal is presented and discussed with a focus on the requirements of the European Noise Directive. Issues concerning data management, calculation procedures, validation of results, and the estimation of exposure of people to noise are addressed. Methodologies adopted in the preparation of noise action plans are portrayed, detailing the drawing of acoustic sensitivity maps, acoustic zoning, conflict identification, together with noise management issues. Noise abatement measures are highlighted with specific examples presented and discussed. Strategies related to the preservation as well as to the development of quiet areas in urban areas are also addressed.. Introduction Recognising that noise, especially from transportation, can be a problem when it becomes excessive, thereby hindering the population s quality of life [], the Portuguese Noise Act of 2000, updated in 2007 [2], requires that all cities and transport infrastructures draw noise maps and prepare noise reduction plans where needed. Large agglomerations with more than 00,000 inhabitants and with a population density of at least 2,500 inhabitants per km 2 as well as large airports, roads, or railways are required to follow the European Noise Directive (END) 2002/9/EC of 25 June 2002 relating to the assessment and management of environmental noise [3] and its more complete set of requirements. Compliance of national regulations in Portugal thus meant that both city councils and transport authorities had to include noise mapping and noise abatement plans in their environmental policies. Since no national calculation methods fit for noise mapping purposes were available, the END interim methods were adopted as from the END transposition in Using the RMR96/SRMII method for railway noise calculation showed some technical difficulties due to its inadequate database. Therefore, a thorough study of the national rolling stock was conducted in order to investigate the possibility of accommodating the use of the railway interim calculation method and its database. In urban areas, noise assessment is crucial, but the management of the quality of the acoustic environment that correlates with annoyance or with well-being, of how people perceive the overall sound composition in context especially during day-time also becomes important. The city s soundscape is much a part of its signature, as it is its visual landscape, lights, or smells. All these issues were taken into account in action plans, incorporating short and long term policies for the management of the acoustic environment []. The Acoustics and Noise Control Group at the University of Lisbon have been working on large scale noise mapping and on action plans of all transport infrastructures and of large cities in Portugal (namely Lisbon, Albufeira, Almada, Funchal, Loures, and Odivelas) since the early 990 s. The first noise maps for the Lisbon airport were drawn in 993 [5]. The city of Lisbon large scale noise map was started in the mid 990 s and was completed by the year 2000 [6].

2 2. NOISE MAPPING 2. Railway noise modelling Since no national calculation methods were available in Portugal for noise mapping, though simple but well calibrated national transportation noise prediction programs had been developed, the END recommended interim methods were adopted as from 2006 when the Directive was transposed, except for railway noise where alternative methods were allowed. In general, the use of the END recommended Dutch RMR/SMRII method in those countries that have not adopted a national method has proved somewhat difficult, since the railway vehicles are usually quite different from country to country and the RMR/SRMII method includes a very specific database with a limited number of vehicle classes, corresponding to the Dutch trains, though new classes can be added. Nevertheless, since the RMR/SRMII propagation algorithm is quite flexible, allowing for a vast number of corrections and adjustments to account for the different acoustical effects found in real situations, which was found to be a valuable asset, a thorough study was carried out in order to make the method applicable. A vast program of measurements of pass-by sound pressure levels and /3 octave band spectra for each type of train vehicle and for different speeds was carried out. An averaging technique was applied, by using samples for different passages of the same type of vehicles, under similar conditions. The /3 octave band reference spectra for the different vehicle classes in the RMR/SRMII database were drawn, for the same conditions. These curves were calibrated for the measured overall noise values. A curve fitting procedure was then followed to find the curve (train class) that best fitted the measured one. This curve fitting procedure was pursued for all types of trains and conditions, to determine the emission values. Corrections were performed for track types, namely long welded or with joints, and conditions, such as rail roughness. The database of emission reference values for all types of vehicles under different conditions of speed and number of wagons was used together with the results of the new measurements. Figure shows the measured /3 octave spectrum curve for a type of suburban train, together with those of different RMR/SRMII classes. 60,0 50,0 0,0 30,0 20,0 0,0 Measured C09 C03 C08 C09r C03m C09+C09r C03+C03m C03+C09 0, Figure : Curve fitting for a type of suburban train. An equivalence table (see Table ) was then drawn between the Portuguese rolling stock and the RMR/SRMII database classes with corresponding corrections making the method possible. A validation procedure showed typical average deviations to be below 2 db [7-8]. Field work on various railway lines later showed a good consistency between measured values and calculations for all the national rolling stock according to this procedure. 2 ICSV23, Athens (Greece), 0- July 206

3 The 23rd International Congress on Sound and Vibration Table : Equivalence between Portuguese rolling stock and RMR/SRMII database classes. Rolling Stock n. units Category RMR96/SRMII Factor rolling stock unit / cat. RMR96/SRMII unit C02 C02 C02 C08 C03 C05(diesel) C06 C09(railcar) C09(carriage) C08 C05(diesel) C03(motor) C05(diesel) C0 C0,, 3,3 3,65 2,00 2,50 UQE 350 UQE 3250 UQE 2300/UQE 200 UQE 3500 UTE 220 UDD 50 CPA 000 UQE 300 UTD 600 LOC5600/2600 LOC930/960 Corail/Sorefame carriage Freight wagon (0m) Units of RMR96/SRMII category per trainset 3,,6 2,5,6 3,0,0,0 2,0,0,0 6,0,0,0 2,5,0 2.2 Strategic and detailed noise maps Strategic noise mapping has been conducted for large transport infrastructures and for large agglomerations to assess the influence of the major noise sources on the overall acoustic environment and to evaluate the population exposure to noise, fulfilling the END requirements. The strategic maps represent a level of information which is quite important for the definition of acoustic environment quality policies by the city councils and by the transportation responsible bodies. They are also instrumental in the macroscopic assessment stage and for the management of noise issues by planners and acousticians. They further became required instruments in new land use plans and in land development plans for licensing purposes in most municipalities. Noise maps are also efficient tools for communication with the population and with decision makers. Most noise maps are available online and some cities provide extracts of the maps with values for the noise indicators (Lden and Ln) corresponding to the areas or buildings specified by the user. Noise abatement studies, developed at the action planning level, however usually require more detailed information than that provided by strategic noise maps. Urban noise management in general also requires information which is not usually included at the strategic level. This calls for a more detailed mapping exercise, with most streets in the urban area and more detailed data on the noise sources being included in the database. Figure 2 compares samples of the strategic and of the detailed noise maps for the central area in the city of Loures, the old city quarters and the downtown area where services and commerce as well as residential areas can be found. Figure 2: Samples of the strategic noise map (left) and of the detailed noise map (right) of the municipality of Loures. Most differences in the two map formats regard road traffic densities. For the strategic noise map calculations, only roads with at least three million vehicle passages a year were considered, according to the END criteria. For the detailed map in the figure, traffic flow densities as low as 350,000 vehicle passages a year were included in the database. For some other cities, a figure of 550,000 passages a ICSV23, Athens (Greece), 0- July 206 3

4 year was considered, depending on the local relevance of the low traffic or on the other parameters determining the resulting traffic noise. The detailed maps allow an insight into virtually every street and building in the city center or in those areas where urban sound management is called for. Not only noise mitigation measures can be designed specifically for each place, but communication with people becomes easier since it is an interesting visual tool yielding much more understandable results than sound levels and helping in managing complaints. 2.3 Population s exposure to noise The exposure of the population to noise was estimated according to the information of the underlying noise maps together with the information on the geographic distribution of the population by official land use areas (Census data). The existing population in Census subsections was allocated to the relevant buildings and the noise levels were calculated at the corresponding façades according to the END definition together with the guidelines in the WG-AEN Good Practice Guide [9]. Examples of the percentage of the population exposed to noise are presented in Table 2 for the municipalities of Lisbon and Odivelas. Table2: Percentage of the population exposed to noise; left: Lisbon; right: Odivelas. Population Exposure to Noise (%) Population Exposure to Noise (%) Noise class [db] Values Noise class [db] Values from to Lden Ln from to Lden Ln ,7 5, , , 3, , ,2 5, ,9 5, ,7 3, ,2 6, ,7 2, ,5, 65 70,5 0, , 0, 70 75,8 0,0 75 0, 0,0 75 0,0 0,0 These values are well in line with those generally found in Europe [0]. 3. Action Plans 3. Noise sensitivity maps Action plans have been drawn for agglomerations and for transport infrastructures that fall into the END categories, but also, though in a somewhat simplified fashion, for any city and transport infrastructure where the population is exposed to noise levels that exceed specified limit values, according to the Portuguese legislation [2]. The contents of the plans depend on the extension of the noise curves but also on the land use and on its sensitivity to noise. The plans aim at reducing noise where necessary and possible, at controlling existing and future sources of noise, and at protecting areas where the acoustic quality is good, for a sustainable development. In this sense, quiet areas are being defined to provide a differentiated soundscape and restoration for the users, especially in urban settings. The noise and the soundscape in particular in each place must be effectively related to the human activities and to the people s expectations if a good acoustical quality is to be achieved []. Our perception of the acoustic environment depends largely on the characteristics of the place but also on our activities during the different periods of the day and on how we expect it to conform to our notion of quality of life. Within the framework of action plan drawing for agglomerations, the land uses and activities in the whole municipal area were extensively surveyed and the correlation with sensitivity to noise thoroughly studied. Usually, well differentiated areas can be found, such as central areas with mixed land ICSV23, Athens (Greece), 0- July 206

5 uses, residential areas, schools, commercial areas, as well as some industrial and leisure activities. In general, four degrees of sensitivity to noise (high, medium, mild and low) were considered, depending on the prevalent activities within areas with a considerable geographical extension. Noise sensitivity maps were then drawn for the whole municipal area based on the existing land uses and activities, considering, for the sake of simplicity, three degrees of sensitivity to outdoor noise: the mild and the low noise sensitive areas were taken as one. At a later stage, the maps were modified to cater for newly planned land uses. Figure 3 depicts land use noise sensitivity maps for the municipalities of Almada and of Albufeira, where the municipal plans for near future development were taken into account. Figure 3: Land use noise sensitivity maps (purple: high; red: medium; brown: mild or low), including near future plans for the municipalities of Almada (left), and Albufeira (right). Three municipal acoustic zones were then defined, each one having distinctive noise limits assigned, according to the national regulations [2]. For the more noise sensitive zones, the limit values were established at 55 db(a) for Lden and at 5 db(a) for Ln. These limits increase to 60 db(a) for Lden and to 50 db(a) for Ln, and to 65 db(a) for Lden and to 55 db(a) for Ln, respectively, in the other two zones. Industrial or similar areas are not considered. By correlating the noise zone maps with the noise maps, conflict maps were drawn and analyzed. These showed limited areas of conflicts, which could somehow be expected given the optimized procedure that had been adopted. Those areas were then studied in detail for noise abatement purposes. 3.2 Noise abatement and management Noise abatement measures and strategies were considered by taking into account the objective sound level reduction, cost-benefit ratios, feasibility and practical issues, and acceptance by the populations. Road traffic noise reduction considered essentially noise barriers and low noise pavements in major roads; speed reductions, road traffic restrictions (especially heavy vehicles), traffic calming measures, mobility changes (including the encouragement of soft modes, where possible), and other strategies were recommended for urban and suburban streets. Railway measures comprised reduction of both airborne sound transmission, adopting tuned rail dampers and noise barriers where feasible and necessary, and of structure-borne transmission by using different resilient vibration isolators []. These later measures were especially considered in urban situations for trams or light rail, given the prominence of the structural sound transmission mechanism. Occasionally, sound insulation reinforcement of façades (especially glass windows) was recommended where other measures were not ICSV23, Athens (Greece), 0- July 206 5

6 effective or feasible. This was a measure adopted near airports though comprehensive studies on aircraft procedures (approach and take-off) were carried out for Lisbon and Oporto airports. The optimized procedures and solutions were adopted upon discussion with the transport authorities. Noise mapping helped to demonstrate the benefits of noise abatement procedures. Figure shows samples of noise maps of an urban area (municipality of Almada) before and after adoption of solutions for noise reduction. Figure : Samples of noise maps of an urban area, before (left) and after (right) implementation of noise mitigation measures, such as speed reduction, low noise pavement and changes in the traffic densities. An effective noise abatement and management program in urban or suburban areas needs the active involvement of all stakeholders, especially the residents. Strategies were defined with the city council officials to call the residents for discussions regarding noise in the city in public sessions. These sessions served both for the experts and urban technicians to understand the citizens concerns and their expectations and to explain them the new plans for urban development and improvement and implementation of solutions for noise abatement purposes. Noise mapping was also used to compare existing and future scenarios and to show the population the benefits of new measures and plans. Discussions with the populations were also useful for the city councils to understand the full extent of the citizens expectation regarding the improvement of the urban environment. This allowed the implementation of further measures and policies for mobility changes and urban development, such as new pedestrian areas, controlled restrictions and limitations on road traffic in city areas, and new green quiet areas for restoration. 3.3 Quiet areas According to the END, areas with good quality of the acoustic environment should be selected, assessed and managed. Currently, no harmonized methodology regarding the definition and protection of quiet areas exists, though there is a general understanding that a quiet area should provide an improved sound environment relative to the surrounding area [2]. Member states have defined more specific criteria, and the Portuguese legislation just requires that in municipal quiet areas noise levels verify Lden < 55 db and Ln < 5 db, which is clearly insufficient. This basis together with criteria for selection (combining quantitative and qualitative parameters) and management (noise mitigation, increasing usability of areas and users satisfaction) were used by some Portuguese municipalities for identifying potential quiet areas. In the city of Almada, a few green areas were identified as possible quiet areas. Some are being developed, based on land and acoustic modelling in order to offer the citizens a space of quiet and psychological restoration. Two examples are shown in Figures 5 and 6. In the city of Odivelas, the identification of green areas with more than 50% of their area having day noise levels Ld < 50 db led to the formal definition of quiet areas in the municipality. 6 ICSV23, Athens (Greece), 0- July 206

7 Figure 5: Peace Park near the central area of Almada.. Conclusions Figure 6: Biological Farm in Almada situated in the urban surroundings. Large scale noise mapping started in Portugal well before the END was approved in Lisbon airport noise maps have been drawn since the early 990 s and the Lisbon noise maps were completed in early The Portuguese Noise Act of 2000 required all cities and transport infrastructures to draw noise maps and to prepare noise reduction plans where noise levels exceed specified limit values. Although the scope of maps and plans was not as wide as in END, this led to an extensive exercise of noise assessment and management. For noise calculations, the interim methods were used as from 2006 when the END was transposed. Although provision for using alternative methods for railway noise was included in the national legislation, an extensive study was conducted so as to adapt the RMR/SRMII database classes to the characteristics of the national rolling stock. An equivalence table was found between the national rolling stock and the database classes. Results on different railway lines showed differences usually much lower than 2 db, making the procedure viable. Larger cities opted not just for strategic noise mapping but also for a more detailed level, developing a tool for planning and management purposes. This enlarged the use of the noise maps for licensing purposes, for land use plans, for new development plans, and for other municipal requirements where urban noise could be an issue. Strategies and solutions for noise mitigation and control were defined together with the responsible body officials and technicians but also with other stakeholders, especially the residents. ICSV23, Athens (Greece), 0- July 206 7

8 Noise maps were generally used as communication tools with the population and with other technicians and decision makers to demonstrate the benefits of noise mitigation measures or to discuss environmental protection strategies. These included the definition of quiet areas especially in urban areas. Action plans were developed to mitigate noise where the levels were found excessive, to control and manage noise for a sustainable development, and to protect and enlarge areas where the acoustic quality is good. ACKNOWLEDGEMENTS This work was conducted under contract between Instituto Superior Técnico, University of Lisboa, and various city councils and transport authorities. Partial support from the Portuguese Foundation for Science and Technology (FCT-CAPS/IST pluriannual funding through the POS_C Program that includes FEDER funds and R&D strategic project) is greatly acknowledged. REFERENCES European Environmental Agency. Good practice guide on noise exposure and potential health effects. EAA Technical Report, n. /200, (200). 2 Portuguese Official Journal. Portuguese Noise Act, approved by Decree-Law 9/2007, of 7/0/2007, (2007). 3 European Commission. Directive 2002/9/EC of the European Parliament and of the Council of 25 June 2002 relating to the assessment and management of environmental noise, published , L89/2-25, (2002). Bento Coelho, J. L. Approaches to Urban Soundscape Management, Planning, and Design, in Soundscape and the Built Environment, Eds. Jian Kang and B. Schulte-Fortkamp, CRC Press, 97-2, (206). 5 Bento Coelho, J. L. Noise Levels Around Lisbon Airport, Proceedings of The 25th International Congress on Noise Control Engineering (Internoise 96), Liverpool, U.K., Vol., p , (996). 6 Bento Coelho, J. L. and Palma, M. J. Lisbon Noise Map, Proceedings of The 29th International Congress on Noise Control Engineering (Inter-noise 2000), Paris, France, Vol , (2000). 7 Bento Coelho, J. L. and Alarcão, D. On railway noise modelling an approach to the European interim method, Proceedings of Acoustics 08, Paris, France, (2008). 8 Alarcão, D. and Bento Coelho, J. L. The adaptation of the interim calculation method for railway noise to the Portuguese rolling stock. Proceedings EURONOISE 2009, Edinburgh, UK, (2009). 9 European Commission. Good Practice Guide for Strategic Noise Mapping and the Production of Associated Data on Noise Exposure, EU Noise Policy Working Group Assessment of Exposure to Noise (WG- AEN), Position Paper, version 2, (2007). 0 European Environmental Agency. Noise in Europe 20. EAA Technical Report, N.º 0/20, (20). Bento Coelho, J. L. and Alarcão, D. Noise action plans in urban and suburban areas a railway experience in Lisbon, Proceedings of the 8 th International Congress on Sound and Vibration (ICSV8), Rio de Janeiro, Brazil, 0 July, (20). 2 European Environmental Agency. Good practice guide on quiet areas. EAA Technical Report, n. /20, (20). 8 ICSV23, Athens (Greece), 0- July 206