2.0 AVIATION NOISE 2.1 MEASUREMENT OF SOUND

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1 The FAR Part 150 process requires a thorough examination of the airport noise environment and depiction of aircraft noise levels on a map that represents the airport area s exposure to noise. This chapter describes the standardized units for noise measurement, computer modeling of aircraft-generated noise levels, and community response to noise. An understanding of the material in this chapter is important for the reader to better comprehend the significance of the noise contours that are presented in Chapters 4.0 and 5.0 and to better interpret the analyses of noise mitigation measures that are presented later in Volume II: Noise Compatibility Program. 2.1 MEASUREMENT OF SOUND Simply defined, sound is sensation perceived by the sense of hearing. The sound that we hear at any given time is the result of a sound source (an airplane, a bell, a television set, etc.) that produces vibration in the air. This vibration in turn produces alternating bands of dense and sparse particles of air, spreading out from the source in a ripple effect. The result of the movement of these bands of particles is a fluctuation in the normal atmospheric pressure, or sound waves. When the sound source stops vibrating, the sound waves disappear and the sound ceases. Sound may be considered beautiful, desirable, or unwanted, depending on the listener s point of view. Noise is usually regarded as unwanted sound that disturbs our routine activities or peace and quiet, and perhaps causes a feeling of annoyance. Which sounds are NOISE is obvious to each listener, and he or she has no need to measure it. It is there, and it is bothersome. How loud (amplitude) a sound is, what frequency (pitch) a sound is, and how long a sound lasts is what causes a sound to be perceived as noise. PART 150 NOISE COMPATIBILITY STUDY - VOLUME I PAGE 2-1

2 2.1.1 Amplitude Sound pressure is the measure of the difference between atmospheric pressure (with no sound present) and the total pressure (with sound present). The amplitude or relative loudness of a sound, i.e., its sound pressure level, is measured in decibels (db). A 0 db sound is the lowest sound detectable by the healthy human ear. Decibels are logarithmic units. 1 Thus, a 10 db increase in a sound seems twice as loud to the listener, while a 10 db decrease seems only half as loud. Amplitude can easily be measured with the aid of a sound level meter that corresponds to the decibel scale Frequency The number of pressure variations per second is called the frequency of a sound. Frequency is measured in cycles per second or Hertz (Hz) and is defined as the number of sound waves per second of an alternating current. The greater the number of Hz, the higher the frequency. The range of human hearing extends from 20 Hz to 20,000 Hz. The most acute frequency range of human hearing is between 1,000 and 4,000 Hz. Because the human ear does not respond to sounds of varying frequency and amplitude in a linear fashion, various weighting factors are applied to noise measurements in an effort to produce results which correspond to human response. These weighting factors are applied to the levels of sound in specific frequency intervals and added or subtracted based on the average human response to sounds in that frequency range; the resultant values are then summed to determine the overall weighted level. The most commonly used weighting system is an A-weighted decibel (dba). The A-weighted decibel de-emphasizes the low- and high-frequency portions of the sound spectrum. This weighting provides a good approximation of the response of the average human ear and correlates well with the average person s judgment of the relative loudness of a PART 150 NOISE COMPATIBILITY STUDY - VOLUME I Page 2-2

3 noise event. 2 A listing of common sounds and their respective dba levels is provided in Exhibit Duration A final characteristic of sound is its duration, or how long it lasts. As an airplane is approaching the observer, its sound reaches a maximum level as it flies directly overhead and then diminishes as the plane moves away. This change in sound pressure level can be illustrated as a bell-shaped curve. 2.2 AIRCRAFT NOISE METRICS Aircraft noise is a composite of noises that an aircraft makes. The major sources of aircraft noise are the machinery noise and the primary jet noise. The machinery noise is the noise generated primarily by the moving parts of the engine such as the fan, compressor, and turbine blades. The primary jet noise is generated by the mixing of the high-velocity exhaust gas from the main body of the engine with the ambient air. The dominant source of noise during takeoff is the primary noise, i.e., generated by the combustion process in the engine, whereas on approach the dominant source is machinery noise, i.e., generated by the physical parts of the aircraft and the movement of air against these parts. Aircraft noise levels will vary according to specific aircraft, location of the aircraft in relation to the ground, weather conditions, and pilot technique. The airport noise environment is comprised of a series of individual aircraft operations, including arrivals, departures, taxiing, overflights, and engine run-ups. These operations may occur frequently and there may be relative quiet between events, reflecting only the ambient (background) noises occurring throughout the community. Aircraft noise has many dimensions, most of these dimensions relate to the reaction of PART 150 NOISE COMPATIBILITY STUDY - VOLUME I PAGE 2-3

4 COMMON SOUNDS Rock Band Ambulance Siren at 100 ft. NOISE LEVEL dba AIRCRAFT NOISE LEVELS dba Motorcycle at 25ft. DumpTruck at 50ft. Vacuum Cleaner at3ft. AirConditioner at 100 ft. Quiet Urban Daytime Quiet Urban Nighttime Soft Whispers at 5ft. Recording Studio Thresholdof Hearing B767(Takeoff) B (Takeoff) A320(Takeoff) CRJ/CL600 (Takeoff) Cessna 150 (Approach) ParkedAirplane 1 Noise LevelsMeasuredforFlyoversat 500 FeetAltitude Adaptedfrom informationcontained in the Federal Interagency Committee onnoise(ficon) TechnicalReport,August BUFFAL O NIAGARA I N T E R N A T I O N A L A I R P O R T SM PART 150 STUDY COMMONSOUNDLEVELS EXHIBIT J:\EXH\RILLO\BUFFALO\PART150\CH2\FINAL\2.1-1COMMONSOUND.CDR 2-4 PBAVIATION

5 people to aircraft noise. These reactions relate to the sound level, the varying sensitivity of the human ear to different frequencies or pitches of sound, the frequency of aircraft noise intrusions, the time of day of these intrusions, and the number of intrusions over a period such as a day. Several metrics have been developed over the years to describe aircraft noise. The goal of these metrics is to quantify aircraft noise in a manner which relates the physical aspects of sound to human assessments of loudness and noisiness. These metrics are the basis of most noise analysis conducted at airports throughout the United States. Four of the more common metrics are presented in following paragraphs. These metrics are particularly important in understanding the aircraft noise analysis for the BNIA: Maximum Sound Level Sound Exposure Level Equivalent Sound Level Day/Night Average Sound Level Maximum Sound Level (Lmax) Human response to noise involves both the maximum level and its duration. One obvious way of describing a sound event is to measure the maximum sound level (Lmax). A distant highway with relatively steady traffic, for example, produces a fairly continuous background sound level with momentto-moment variations of only a few dbs. In contrast, an aircraft overflight produces a distinct, transient noise event. During an aircraft overflight, the sound level emerges out of the fluctuating background environment, continues to increase until the aircraft passes the observer, and then decreases to blend in with the background noise as the aircraft recedes into the distance. It is desirable to use a single number for describing this metric. This value is easy to measure, requiring an observer to simply note the maximum reading on a sound-level meter. It is also easy to describe because most people can relate to PART 150 NOISE COMPATIBILITY STUDY - VOLUME I PAGE 2-5

6 the loudest part of a noise event. Exhibit shows two aircraft events with the same Lmax value. The Lmax for both events is 85 dba even though the duration of the sound is longer for the second event Sound Exposure Level (SEL) SEL is a measure of the A-weighted total sound energy of a single noise event, such as an aircraft flyover, represented as the A-weighted decibel level of that event including its amplitude, frequency, and duration. One way to understand SEL is to think of it as the sound level that one would experience if all of the sound energy of a single event occurred in one second. This normalization to a duration of one second allows the direct comparison of sounds of different durations. The SEL concept is illustrated in Exhibit As shown, the noise level rises to a peak and then subsides to the ambient or background noise level. The energy under the curve and the energy in the SEL have the same total weighted sound energy when integrated over time. This measure is very helpful in computing the Equivalent Sound Level (Leq) and Day/Night Sound Level (DNL), which are typically used in describing environmental noise and calculating aircraft noise impacts. Referring back to Exhibit 2.2-1, although the Lmax values for two aircraft events are the same level, they have different SEL values. Aircraft Event B has a higher SEL value because it has a longer duration. Exhibit depicts aircraft noise footprints for a comparative SEL value of 95 dba and illustrates the difference in comparable SEL levels for Stage 1, Stage 2 and Stage 3 aircraft. Not to be confused with stage length, i.e. the distance an aircraft travels, Stages 1, 2, and 3 refer to noise standards established PART 150 NOISE COMPATIBILITY STUDY - VOLUME I PAGE 2-6

7 Duration (second) Source: PBAviation BUFFAL O NIAGARA I N T E R N A T I O N A L A I R P O R T SM PART 150 STUDY MAXIMUMSOUNDLEVEL(Lmax) EXHIBIT J:\EXH\RILLO\BUFFALO\PART150\CH2\FINAL\2.2-1 MAXIMUMSOUNDLEVEL(Lmax).CDR 2-7 PBAVIATION

8 SEL=105 db Lmax=101 db ReferenceDuration (1Second) Time(Seconds) Source: Federal InteragencyCommittee onnoise (FICON)Technical Report, Page B-6,August BUFFAL O NIAGARA I N T E R N A T I O N A L A I R P O R T SM PART 150 STUDY SOUNDEXPOSURELEVEL CONCEPT EXHIBIT J:\EXH\RILLO\BUFFALO\PART150\CH2\FINAL\2.2-2 SOUND EXPOSURE.CDR 2-8 PBAVIATION

9 BUFFAL O NIAGARA I N T E R N A T I O N A L A I R P O R T SM PART 150 STUDY COMPARATIVEAIRCRAFT NOISE FOOTPRINTSATDIFFERENT STAGES EXHIBIT J:\EXH\RILLO\BUFFALO\PART150\CH2\FINAL\2.2-3 COMPAREFOOTPRINTS.CDR 2-9 PBAVIATION

10 by Federal Aviation Regulations (FARs). Over the years, these noise standards have been very beneficial in reducing aircraft noise impacts, and compliance has necessitated a substantial commitment on the part of the nation s airlines to replace and re-engine their aircraft. Under FAR Part 36, jet aircraft greater than 75,000 pounds were required to comply with Stage 2 noise standards by January FAR Part 91 required that all jet aircraft greater than 75,000 pounds meet Stage 3 noise standards by the end of 1999 with limited waivers through (No waivers were granted for the carriers that operate at the BNIA.) Stages 1 and 2 aircraft such as B and DC9Q9 are noisy aircraft. Fortunately, Stage 1 and 2 aircraft have been phased out of the fleet or hush-kitted to comply with Stage 3 requirements. Stage 3 aircraft like the B are quieter. Exhibit compares aircraft noise footprints for a variety of airplanes currently in use at the BNIA based on a SEL value of 95 dba Equivalent Sound Level (Leq) Individual sound events may occur only once, or may occur several times during the day in a neighborhood. The number of times these events occur is also important in measuring the noise environment. One way to describe this factor might be to count the number of events per day for which the SELs exceed a given level such as 80 db, plus the number which exceed 75 db, plus the number which exceed 70 db, and so on. A more efficient way to describe both the number of such events and the sound exposure level of each is the time-average of the total sound energy over a specified period (i.e., one minute, one hour, one day, etc.). This way of describing sound is referred to as the equivalent sound level (Leq). Leq includes peak sounds as well as valleys within a particular time frame. The purpose of Leq is to identify the average noise level over a period of time. The metric is A-weighted and accounts for all of the sound energy occurring during a particular period of time. Leq is easily measured with sound equipment. PART 150 NOISE COMPATIBILITY STUDY - VOLUME I PAGE 2-10

11 BUFFAL O NIAGARA I N T E R N A T I O N A L A I R P O R T SM PART 150 STUDY COMPARATIVEAIRCRAFT NOISEFOOTPRINTS EXHIBIT J:\EXH\RILLO\BUFFALO\PART150\CH2\FINAL\2.2-4 COMPAREFOOTPRINTS.CDR 2-11 PBAVIATION

12 Typical sounds one might hear in a quiet residential neighborhood are illustrated in Exhibit As shown, these sounds would produce an Leq of approximately 58 db. This accounts for all of the sound energy during the sample period, and provides a single-number descriptor in terms of sound energy Day/Night Average Sound Level (DNL) One additional factor is also important in measuring a sound environment the occurrence of sound events during nighttime. People are normally more sensitive to intrusive sound events at night, and the background sound levels are normally lower at night because of decreased human activity. Therefore a penalty may be added to sound levels which occur during night hours, to include these factors. By convention, a 10 dba penalty is added to sound levels occurring between 10:00 p.m. and 7:00 a.m. The 24-hour average sound level, including this 10 dba penalty, is known as the day/night average sound level (DNL). This 10 dba penalty means that one nighttime sound event is equivalent to 10 daytime events of the same level. DNL, formerly referred to as Ldn, was developed as a single measurement of community noise exposure. DNL was introduced by the Environmental Protection Agency (EPA) as a simple method for predicting the effects of the average long-term exposure to environmental noise on a population. In the FAR Part 150 process, it is the primary system for measuring noise impacts. Federal Department of Housing and Urban Development (HUD) regulations also include DNL as the standard for measuring outdoor noise environments. The SELs from aircraft events are averaged over a 24-hour period to determine the DNL. DNL differs from SEL in that it focuses on a number of events rather than a single event; however the Integrated Noise Model (INM) utilizes SEL for each aircraft event to determine the DNL. PART 150 NOISE COMPATIBILITY STUDY - VOLUME I PAGE 2-12

13 Family Car Aircraft Overflight Cars on Nearby Boulevard Sports Car 2 Dogs Barking Distant Car 58 Leq Time in Minutes Source: Condensed from information contained in the Federal Interagency Committee on Noise (FICON) Technical Report, August BUFFALO NIAGARA SM I N T E R N A T I O N A L PART 150 STUDY EXHIBIT NEIGHBORHOOD SOUND LEVELS A I R P O R T J:\EXH\RILLO\BUFFALO\PART 150\CH2\FINAL\2.2-5 NEIGHBORHOOD SOUND.CDR PB AVIATION

14 2.3 NOISE MODELING In 1978, the FAA released the first version of a computer simulation model designed to assess aircraft noise impacts. The FAA continually refines this model to keep pace with changes in aircraft noise technology. Today, the FAA-approved Integrated Noise Model (INM) is the standard aircraft modeling program at civilian airports. 6 Since its introduction, five additional versions of the INM have been released, and its aircraft database has been updated numerous times to reflect changes in the existing and projected aircraft fleet mixes. The most recent version, INM 6.1, was utilized for this Part 150 Study. This version includes a database on aircraft noise and performance characteristics representative of individual commercial, general aviation, and military aircraft types powered by turbojet, turbofan, and propeller-driven engines. The INM incorporates detailed information about each aircraft, including departure profiles for applicable trip lengths, approach profiles, and SEL versus distance curves at various thrust settings. Surrounding terrain data can also be considered when the INM is used INM Input The INM calculates noise exposure levels from airport-specific data that are input to the model. These data include runway coordinates, flight tracks, fleet mix, activity levels, runway and flight track utilization, and time of day. The model takes into account arrival, departure, touch-and-go, overflight, and run-up operations. The INM user provides the activity and operational data in an input file for each noise impact scenario under evaluation. Activity information includes the number and type of operation. Operations are further defined based upon the fleet mix and time of day. Care is taken to ensure that the file reflects an accurate mix of typical aircraft in use at the airport. Fleet mix is determined by observation, operational records, and flight schedules. The time of day specification is an PART 150 NOISE COMPATIBILITY STUDY - VOLUME I PAGE 2-14

15 important factor in the calculation of DNL because those operations that occur between 10:00 p.m. and 7:00 a.m. receive a 10 dba penalty to account for increased noise sensitivity during sleeping hours. The runway definitions establish the airport geometry and its relationship to the surrounding area. A flight track is a user-defined flight path projected on the ground from a reference point on a runway. Each flight track is associated with a runway and is used for one type of operation: takeoff, landing, touch-and-go or overflight. Usually, a runway will have several tracks for each type of operation. An important point to understand when reviewing the input assumptions for an aircraft noise analysis is that aircraft do not follow precise paths upon their arrival to or departure from the airport. Rather, aircraft follow a routing and there is considerable dispersion along the route. Analysis of radar data produces a spaghetti-like picture of flight activity and indicates the principal corridors of flight. To account for this dispersion, the INM enables the user to create subtracks along side of a backbone flight track and automatically distribute flight operations across sub-tracks INM Output The INM requires both the user input and the model database to operate. This information is processed through a series of algorithms that produce calculations of noise exposure levels. When computer-plotted, these calculations take the form of a line drawing that connects points of equal noise exposure. These drawings are commonly referred to as noise contours. FAR Part 150 requires the development of DNL 65, 70, and 75 dba noise contours. When placed over a map of the airport area, the contours enable the analyst to identify the number of people, homes, and total area exposed to aircraft noise for these levels. The INM can also calculate individual noise measurements at specific points or grids at particularly noise-sensitive structures in the airport vicinity, such as hospitals or schools. PART 150 NOISE COMPATIBILITY STUDY - VOLUME I PAGE 2-15

16 The INM models average annual day aircraft noise impacts, that is, the average level of sound that occurs during a 24-hour period, taking into account times when the airport is busy and times when there is less activity. FAR Part 150 requires analysis of average annual day noise levels rather than single-event or peak noise levels. The use of an annual average day can be very confusing to individuals who are not familiar with aircraft noise assessment methodologies. The noise analyst uses 12 months of data, dividing this amount of activity by 365 (or 366 for a leap year) to derive an average day and not a day that is observable. Even more confusing, runway end use is depicted as the average over the 12- month period which also is not observable. Airfields are operated in a flow pattern, depending on the wind. Even though there may be a predominant flow, or configuration for operating the airfield, the annual average day considers all operating configurations, proportionately. It is not possible to use sound level meters to measure the DNL levels, unless the meters are in place over the entire 12-month period, and the 10 dba penalty is added to all night events. Nevertheless, the DNL is the federally-approved methodology and the guidelines for its interpretation are well established. 2.4 COMMUNITY RESPONSE TO NOISE Most individuals in urbanized areas are exposed to varying noise levels from many sources as they go about their daily activities. The degree of disturbance or annoyance of unwanted sound depends on three factors: the amount and nature of the intruding noise, the relationship between the background noise and the intruding noise, and the type of activity occurring when the noise is heard. Ambient noise is the total background noise at a given place and time consisting of a composite of sounds from varying sources and distances. It is the collection of natural and man-made sounds. People are generally not aware of ambient (background) noise, but normally hear noises (such as fireworks, delivery trucks, or honking horns) that contrast PART 150 NOISE COMPATIBILITY STUDY - VOLUME I PAGE 2-16

17 sharply with ambient levels. Because background noise is so familiar, it is less annoying even when it approaches decibel levels considered uncomfortable if generated from a specific source. Individuals tend to judge the annoyance of an unwanted sound in terms of its relationship to background noise. The roar of an aircraft at night when background noise levels are low (approximately 45 dba) is generally more objectionable than the roar of an aircraft in the afternoon when background noises are higher (approximately 60 dba). It is important to note that individuals have differing sensitivities to noise. Loud noises bother some people more than others. The rhythm of the noise also affects whether or not it is objectionable. Noises occurring during sleeping hours are usually considered to be much more objectionable than the same noise during the daytime. Another factor to consider is how the noise interferes with activities. In a 60 dba environment, normal conversation is possible while sleep may be difficult. Work activities requiring high levels of concentration may be interrupted by loud noises, while outside sports activities may not be interrupted at all. In general, community response to noise is based on people's perception of its effects on: Annoyance Sleep/speech interference Health Property values Annoyance The most common human reaction to aircraft noise is annoyance. Annoyance is a summary measure of the general, adverse reactions of people to noises which disrupt their daily activities such as telephone conversations, TV/radio listening, sleep, or simple tranquility. People are also influenced by physical factors such as time of day, season of the year, and control over the noise source. The actual intensity and frequency of the noise also influences reaction. PART 150 NOISE COMPATIBILITY STUDY - VOLUME I PAGE 2-17

18 Currently, the best measure of this reaction is the percentage of people who characterize themselves as highly annoyed by long-term exposure to their noise environments. Exhibit relates DNL and percentage of people who said in research studies they were highly annoyed by transportation noise. 8 Some studies found that communities report themselves slightly more annoyed by aircraft noise than by surface transportation noises. As depicted in Exhibit 2.4-1, average community annoyance is expected to be significant at DNL levels of 65 to 70 dba. Above DNL 70 dba, community annoyance is expected to be severe. In analyzing the results of numerous social surveys conducted at major airports in several countries, one researcher noted that when exposed to aircraft noise levels of DNL 65 dba, 25 percent of residents are seriously annoyed, an additional 35 percent are annoyed, and the remaining 40 percent are not annoyed. With aircraft noise levels of DNL 75 dba, approximately 60 percent of residents are seriously annoyed, an additional 30 percent are annoyed, and the remaining 10 percent are not annoyed Sleep/Speech Interference Sleep is a necessary part of life with important beneficial effects that interference may inhibit. There is much debate over the cumulative effects of aircraft noise on sleep. A composite of data for sleep interference versus maximum A-weighted indoor noise levels is presented in Exhibit For example, at a maximum interior noise level (Lmax) of 65 dba, approximately 50 percent of the population will experience a change in sleep state and 25 percent will be awakened. Research PART 150 NOISE COMPATIBILITY STUDY - VOLUME I PAGE 2-18

19 Day-NightAverageSound Level(dB) USAF(1992) Schultz (1978) Source: Federal InteragencyCommittee onnoise (Ficon)Technical Report,August BUFFAL O NIAGARA I N T E R N A T I O N A L A I R P O R T SM PART 150 STUDY COMPARATIVEEFFECTS OF NOISE INCOMMUNITYENVIRONMENTS EXHIBIT J:\EXH\RILLO\BUFFALO\PART150\CH2\FINAL\2.4-1 COMPAREEFFECTSNOISERES.CDR 2-19 PBAVIATION

20 50 Sleep Stage Changed Awakened from Sleep MaximumIndoor dba Source: J. StevenNewman andkristyr.beattie, Aviation Noise Effects,FederalAviation AdministrationOffice of Environment and Energy,NoiseAbatement Division, March1985. BUFFAL O NIAGARA I N T E R N A T I O N A L A I R P O R T SM PART 150 STUDY SLEEPINTERFERENCE VS. MAXIMUM A-WEIGHTEDSOUNDLEVELS EXHIBIT J:\EXH\RILLO\BUFFALO\PART150\CH2\FINAL\2.4-2 SLEEPINTERFERENCEVSMAX.CDR 2-20 PBAVIATION

21 indicates that an exterior sound level of approximately 72 dba is an acceptable interference threshold for a windows-closed condition. An exterior noise level of 72 dba corresponds to an interior level of approximately 55 dba. 11 This threshold is important in assessing the impacts of nighttime airport operation. A study conducted in Great Britain concerning aircraft noise and sleep disturbances, concluded that, aircraft noise has a negligible effect upon overall patterns of arousal from sleep. Even at locations close to airports with higher levels of night aircraft traffic, the additional disturbance caused by the aircraft noise, both wakenings and lesser arousals, is likely to be very small compared to that occurring naturally due to all other causes. Aircraft noise itself is most unlikely to increase sleep disturbance rates to the point at which after effects upon health or performance would be noticeable. 12 Speech interference is a principal factor in human annoyance response. It is especially critical in situations requiring a high degree of intelligibility for safety. Quality speech communication is important in the classroom, office, and industrial setting. Several factors, including distance from the speaker and loudness of voice, contribute to interference. Exhibit 2.4-3, developed by the EPA, relates speech interference levels to levels of effective communication depending on the noise level and distance between the talker and listener. At 65 dba, for example, normal speech communications can continue with individuals who are approximately five feet apart Health Human response to aviation noise may be influenced by a belief that exposure to it will damage health. It is widely believed that continuous exposure to high levels of noise will damage human hearing. At 120 dba, considered the PART 150 NOISE COMPATIBILITY STUDY - VOLUME I PAGE 2-21

22 Communication Impossible Communication Difficult Communication Difficult Areaof NearlyNormal SpeechCommunications TalkertoListenerDistancein Feet Source: U.S. EPA,Report to thepresident and Congress on Noise BUFFAL O NIAGARA I N T E R N A T I O N A L A I R P O R T SM PART 150 STUDY SPEECH INTERFERENCELEVELS EXHIBIT J:\EXH\RILLO\BUFFALO\PART150\CH2\FINAL\2.4-3 SPEECHINTERFERENCE.CDR 2-22 PBAVIATION

23 threshold of discomfort, there may be a tickling sensation in the middle ear. At 140 dba, the threshold of pain, sound pressure may cause auditory fatigue or acoustical failure. Studies have indicated, however, that hearing loss is not likely to result from aircraft overflights. A laboratory study conducted near Los Angeles International Airport exposed groups of young men to recorded aircraft flyover noise consisting of 40 events per hour, each event with a maximum level of 111 dba, over six one-hour periods. 14 The measured Temporary Threshold Shift (TTS), a constant measure of the effects of a single day's exposure to noise, was negligible for the young men. Because TTS is considered to represent a precursor to permanent hearing loss, the study indicated there is no danger of permanent hearing loss resulting from high levels of aircraft noise. The federal Occupational Safety and Health Administration (OSHA) has issued regulations to protect the hearing of industrial workers. These regulations, which prescribe permissible noise limits for various amounts of time, are shown in Table TABLE Buffalo Niagara International Airport PERMISSIBLE NOISE EXPOSURE 1 Duration Per Day(Hours) Sound Level(dBA) ½ ½ 110 ¼ or less 115 Source: OSHA, Code of Federal Regulations, Title 29, Chapter 27, Part When the daily exposure is composed of two or more periods of noise exposure of difference levels, their combined effect should be considered, rather than the individual effect of each. PART 150 NOISE COMPATIBILITY STUDY - VOLUME I PAGE 2-23

24 OSHA standards, while not a requirement of FAR Part 150, are not typically exceeded in the vicinity of an airport. Nonauditory health issues that have been researched and linked to aircraft noise include cardiovascular effects, achievement scores, birth weight, mortality rates, and psychiatric admissions. While some studies have shown a significant correlation, others have shown none. Research continues, but there are no conclusive studies to corroborate the cause and effect theory Property Values The effects of aircraft noise on real estate values have been analyzed by the FAA as well as independent researchers. The conclusion of the FAA, as documented in FAA Report No. FAA-EE-85-2, Aviation Noise Effects, is that while studies do corroborate the public point of view that aircraft noise may decrease the value of property, there are many other factors that affect the price and desirability of a residence. 16 The absence or presence of aircraft noise is just one of many considerations faced by the consumer in buying or selling a residence. A number of socioeconomic factors other than aircraft noise can negatively affect real estate values. Such factors include: Size of the house Condition of the house Physical amenities (i.e., air conditioning, garage, etc.) Distance from a business district Number of parks, schools, or other community facilities in the area PART 150 NOISE COMPATIBILITY STUDY - VOLUME I PAGE 2-24

25 * * * * * * * * 2.0 AVIATION NOISE One additional piece of knowledge concerning the compatibility of differing land use types with differing levels of aircraft noise is necessary prior to presenting the noise contours. The next chapter, Chapter 3.0, describes land use compatibility criteria, as established by the FAA's requirements, and reviews the status of existing land uses in the vicinity surrounding the BNIA. The noise assessment methodologies discussed in this chapter form the basis for understanding the aircraft noise exposure contours that are presented in Chapters 4.0 and 5.0. PART 150 NOISE COMPATIBILITY STUDY - VOLUME I PAGE 2-25

26 ENDNOTES Federal Interagency Committee on Noise (FICON), Federal Agency Review of Selected Airport Noise Analysis Issues, Appendix B Sound Basics, page B-2, August J. Steven Newman and Kristy R. Beattie, Aviation Noise Effects, Federal Aviation Administration Office of Environment and Energy, Noise Abatement Division, March Melville C. Branch, et. al., Outdoor Noise and the Metropolitan Environment, Los Angeles Department of City Planning, 1970, p.2. U.S. Environmental Protection Agency, Calculation of Day-Night Levels (Ldn) Resulting from Civil Aircraft Operations, EPA 550/ , National Technical Information Service PB 266, January U.S. Environmental Protection Agency, Protective Noise Levels, Condensed Version of EPA Levels Document, November FICON, Federal Agency Review of Selected Airport Noise Analysis Issues, Appendix B Sound Basics, page B-18, August Federal Aviation Administration Office of Environment and Energy, INM User s Guide, Page 7-7, September Federal Interagency Committee on Noise (FICON), Federal Agency Review of Selected Airport Noise Analysis Issues, pages 3-6 and 3-8, August J. Steven Newman and Kristy R. Beattie, Aviation Noise Effects, Federal Aviation Administration Office of Environment and Energy, Noise Abatement Division, March J. Steven Newman and Kristy R. Beattie, Aviation Noise Effects, Federal Aviation Administration Office of Environment and Energy, Noise Abatement Division, March Actual dba levels may vary from structure to structure; however, FAA guidelines indicate an average difference of 20 dba with a windows-closed situation. 12 Great Britain, Department of Transport, Report of a Field Study of Aircraft Noise and Sleep Disturbance, December U.S. EPA, Report to the President and Congress on Noise, Ward, Cushing & Burns, TTS From Neighborhood Aircraft Noise, Journal of Acoustical Society of America, Vol. 61, No. 1, July PART 150 NOISE COMPATIBILITY STUDY - VOLUME I Page 2-26

27 15 Occupational Safety and Health Administration, Code of Federal Regulations, Title 29, Chapter 27, Part J. Steven Newman and Kristy R. Beattie, Aviation Noise Effects, Federal Aviation Administration Office of Environment and Energy, Noise Abatement Division, March PART 150 NOISE COMPATIBILITY STUDY - VOLUME 1 PAGE 2-27