La ciudad de Madrid registró en marzo una media de 63,63 decibelios de contaminación acústica, lo que sitúa a la capital en niveles cercanos al máximo de ruido soportable, establecido por la Organización Mundial de la Salud (OMS) en 65 decibelios ponderados, según el Área de Medio Ambiente del Ayuntamiento de Madrid.
De las 27 estaciones operativas, 11 superaron este nivel, lo que significa que el 40 por ciento de las calles residenciales madrileñas están fuertemente contaminadas por ruido, según informes de la OMS. Entre las zonas que más contaminación acústica soportan se encuentran las calles Santa Eugenia, con 70,9 decibelios; Doctor Gregorio Marañón, con 70,3 decibelios; seguida por el Paseo de Recoletos (69,8); y la avenida de Ramón y Cajal, con 68,8 decibelios anotados, todas ellas calles por donde circulan diariamente miles de vehículos.
Por el contrario, según datos del Ayuntamiento de Madrid, las zonas de la capital que soportan menos contaminación acústica están situadas en la Casa de Campo, con 50,6 decibelios; la calle General Ricardos, con 55; y Vallecas, con 57,7, zonas alejadas del centro de la capital.
El Departamento de Calidad del Aire municipal cuenta con 30 estaciones de Medición Medioambiental dentro la Red de Vigilancia que se encargan, a través de micrófonos especializados, de establecer datos diurnos y nocturnos de todas las zonas de Madrid. Las de la Glorieta de Carlos V, la Plaza de Castilla y Villaverde se encuentran actualmente fuera de servicio, debido a las obras de la zona. Asimismo, cuentan con varias unidades móviles, que se encargar de hacer mediciones puntuales y concretas, la conocida como ‘patrulla antiruido’.
Respecto al nivel de ruidos nocturnos, que comprende la medición entre las 23 y las 7 horas, el Departamento de Calidad del Aire recomienda que no se superen los 55 decibelios. Según los datos registrados el miércoles, día laborable, por los sistemas de medición municipal, todas las estaciones superaron ese límite, salvo las situadas en las zonas de El Pardo, Casa de Campo, y General Ricardos y Vallecas.
Los fines de semana, concretamente las noches de viernes y sábado, los niveles de ruido aumentan sensiblemente en la zona centro de la capital, debido al aumento del transporte y a la actividades de los locales de ocio. Así, vecinos de las calles aledañas a la puerta del Sol, Gran Vía, Chueca, Plaza de Huertas y el barrio de La Latina se quejan reiteradamente de los estruendos que provocan la acumulación de gente en zonas de marcha.
La Ordenanza del Ayuntamiento de Madrid de 2004 sobre Protección de la Atmósfera contra la Contaminación por Formas de Energía establece diferentes niveles máximos de ruido, que oscilan entre los 50 y 80 decibelios diurnos y los 45 y 75 nocturnos dependiendo de cinco tipos de áreas urbanas diferenciadas.
Entre las actividades causantes del ruido, aparecen en primer lugar el tráfico, y luego las obras y otras actividades laborales y la industria. Los efectos producidos por el ruido pueden ser fisiológicos, como la pérdida de audición, y psicológicos, como la irritabilidad exagerada, según informa el Área de Medio Ambiente del Ayuntamiento de Madrid.
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Excessive traffic noise is one of the most common complaints among residents. Millions of people are affected by constant traffic noise in their own home. In fact, traffic noise impacts more people than any other environmental noise source. Traffic noise can affect the ability to work, learn, rest, relax, sleep, etc. Excessive noise can lead to mental and physical health problems. If your home is near a major road or you are experiencing problems with traffic noise, you may be able to limit the impact on yourself and your family.
There are basically four options for controlling traffic noise: constructing (or increasing the height of) a barrier wall, increasing the isolation quality of the home, masking the noise, or controlling the noise directly at the source.
Barrier Walls
Constructing or increasing the height of a barrier wall could result in a noticeable decrease in traffic noise. However, certain guidelines must be met in order for the wall to be effective:
Material
The wall must be solid with no penetrations in order to be effective. Any penetration, opening or gate can degrade the effectiveness of the barrier. Concrete walls are preferred, but other types of walls can also be effective. A barrier does not have to be a wall, it could also be a large earthen berm. A common misconception is that typical landscaping or vegetation can act as an effective barrier for traffic noise. Unless the vegetation is 100′ thick and very dense, it will provide very little if any noise reduction.
Distance
Typically, a barrier is more effective the closer it is to the source or to the receiver. Noise barriers are generally only effective for homes within 300 ft. of the roadway.
Height
The noise from automobile traffic is primarily from the tires on the pavement. This noise source is at 0′ above the ground. Noise from large trucks is typically engine and exhaust noise and is approximately 8′ above the ground. In order to be effective, a barrier wall must at least block the line of sight from the noise source to the receiver. Although a 6′ high wall can help to reduce auto traffic noise, it will do little if anything for heavy truck traffic. On the same note, if a home is on a hill or elevated above the roadway, a 6′ high wall may not be adequate in blocking the line of sight, even for auto traffic.
Increasing the height of an existing wall by 1-2 ft. may make a difference depending on the line of sight issues mentioned above. However, if the wall already blocks the line of sight, increasing the height of the wall by a couple of feet will not provide a noticeable reduction. In fact, the Department of Transportation states the general rule of thumb: each 1 ft. of height added to a wall, above the height that breaks the line of sight between the source (traffic) and receiver (residence), reduces the noise level by ½ decibel (see table below).
Isolation Quality
Traffic noise can also be controlled at the receiver by increasing the isolation quality of the home. Noise is transmitted primarily through the weakest points. Almost always, the weakest points in the home would be the windows. Depending upon the isolation quality of the current windows, upgrading the window assemblies could provide at least some relief. Replacing the windows will not help dramatically if you already have decent windows.
Window isolation quality is expressed as a Sound Transmission Class (STC) rating. The higher the rating, the better the isolation quality of the window. A typical single pane window has an STC rating of 22-25. A typical dual pane window has an STC of 27-32. (See table below). Specialty windows with higher STC ratings are also available.
In existing residences it could be very costly to replace the majority of the windows. Another option that may be less expensive and could produce even better results is to add a window insert in addition to your existing windows. The window insert is placed inside your existing window sill.
Please note that it is important to upgrade the windows that are both parallel and perpendicular to the roadway. It is almost never worthwhile to do anything to the exterior wall of the home, particularly if there is a window(s) in the wall. If the noise does not appear to be transmitting through the windows seek the help of a professional for further options. Contact us for a referral database of acoustical consultants.
Masking
Noise can also be masked at the receiver. Sound masking can be implemented outside or inside your home. This can be accomplished by an electronic sound masking system playing white noise/pink noise through noise generators. Other options include, indoor and outdoor water features, fans, or recordings of soothing sounds. However, this is sometimes perceived as adding more noise to a noisy environment. To learn more about masking systems, click here.
Control At The Source
As a resident you may not be able to control traffic noise at the source, but there are ways of limiting problems with traffic noise in the design of future roadways. Traffic noise increases with higher speed limits and with shorter distances from the road to the home. Recessing the roadway can reduce the noise impact. Use of quiet pavement such as rubberized asphalt can also reduce the impact by 4-5 decibels (see table below). Unlike conventional asphalt, rubberized asphalt maintains its noise reduction properties over several years.
www.ecospip.org/archivo/movilidad/Julio_Diaz_Ruido_Trafico_Salud.pdf
