Effects of Aircraft Noise: Research Update on Select Topics (2008) / Chapter Skim
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Appendix A - Discussion of Topic Issues
Appendix A - Discussion of Topic Issues
Pages 30-89
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From page 30... ...
Considerable research, review of previous research with new thought, new independent research, and collaborative efforts to identify health effects related solely to aviation noise have been completed; most can be condensed into impacts in three primary categories: the cardiovascular system, children, and hearing impairment. Cardiovascular Effects Several recent studies have reviewed previous literature, either through compilation or re-review of original data, which suggests that increased hypertension or other cardiovascular effects may be associated with particular long-term noise exposure.
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From page 31... ...
are a primary risk factor. Because aviation and typical community noise levels near airports are not comparable to the occupational or recreational noise exposures associated with hearing loss, hearing impairment resulting from community aviation noise has not been identified.
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The study is subject to the problems of a cross-sectional study in which subjects in one area of noise exposure are compared with subjects in a different area of noise exposure. Furthermore, the study results identified increased hypertension at noise levels as low as 50 dBA Leq, which is lower than typical ambient noise levels in urban areas and lower than ambient noise levels in many suburban areas.
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From page 33... ...
The author identified studies that show the threshold for higher risk for hypertension to be "day-time outdoor levels of considerably more than 80 dBA," although "the reviewers determined the respective thresholds of at least 70 dBA for hypertension and between 65 and 70 dBA for ischemic heart diseases." The author noted that difficulties to determine causal relations increase with the time lag between the onset of noise exposure and the manifestation of an effect in question. Another important factor is habituation, which causes a reduction of primary and secondary responses with time.
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Noise exposure was assessed using noise models with a resolution of 1 dB (5 dB for UK road traffic noise)
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The authors report that there is sufficient scientific evidence that noise exposure can induce hearing impairment, hypertension, ischemic heart disease, annoyance, sleep disturbance, and decreased school performance. The evidence is limited for other effects, such as changes in the immune system and birth defects.
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Air traffic noise exposure was positively associated with the consultation of a general practitioner or specialist, the use of cardiovascular medicines, and angina pectoris. In cross-sectional studies, road traffic noise exposure increases the risk of myocardial infarction and total ischemic heart disease.
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The methodology employed is somewhat complex, but is useful for considering the potential for hearing loss from environmental exposure to aircraft noise. Typical community noise levels near an airport are not comparable to the occupational or recreational noise exposures that are associated with hearing loss.
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From page 38... ...
Further, it may be that the intermittency of environmental noise may itself protect hearing from damage." CHAPTER THREE: ANNOYANCE AND AVIATION NOISE Before addressing recent studies related to exposure-response relationships between transportation noise and community annoyance, a brief historical overview is warranted. With the development of jet aircraft technology in the early 1950s, concern about exposure to noise from transportation sources led to the publication of the initial scientific studies of aircraft noise exposure and the responses of communities in the vicinity of airports and, later, for road traffic and railway noise.
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From page 39... ...
. In later years, the primary author criticized the use of this simplistic curve, in light of the high data variability, the effect of low- and highnoise exposure levels on the curve fit, and the lack of consideration of other variables in community response to noise.
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"A disproportionately large and long-term increase was observed in the prevalence of self-reported high annoyance long after a step increase in aircraft noise exposure .
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Furthermore, more recent research tends to support the idea that the dose-response curves are different for aircraft, road, and rail noise sources. An area of research that remains to be investigated is the relationship between single-event noise levels and annoyance.
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policy on aviation noise. It was written more than a decade after Shultz synthesized the findings from a dozen social surveys and reported on the relationship between community noise exposure and the prevalence of annoyance.
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Silvati, and E Haboly, "Social Survey of Community Response to a Step Change in Aircraft Noise Exposure," The Journal of the Acoustical Society of America, Vol.
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The surveys show considerable variation in the level of noise exposure required to elicit self-reports of consequential degrees of annoyance. The distributions of the criteria for reporting annoyance with aircraft and with other noise sources overlap considerably, but the mean value of the criterion for reporting annoyance is about 5 dB more tolerant of non-aircraft exposure.
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From page 45... ...
Noise Exposure Different Metrics and Noise Characteristics Noise is present everywhere in our everyday life and sleep disturbance resulting from excessive noise has been studied in a variety of environments; however, the effects of transportation noise have been studied the most. Different indices have been used to describe various community noise exposures, and there is no general agreement on which should be preferred among the various integrated energy indices (e.g., Leq, Lden/CNEL, DNL, and Lnight)
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From page 46... ...
The following list includes some of the various objective physiological, biochemical, and behavioral measures used to assess the immediate effects of night-time noise: • EEG arousal responses, • Sleep stage changes, • Nocturnal awakenings, • Total waking time, and • Autonomic responses. After Effect Measures Other measures made after night-time noise exposure include daytime performance and cognitive function deterioration analyses.
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From page 47... ...
is not the only acoustical factor that influences sleep disturbance. Therefore, attention is being given to the role of other factors, notably the actual noise exposure at the façade of the bedroom, and the difference between outdoor and indoor noise levels (sound insulation)
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Annotated Bibliography -- Sleep Disturbance and Aviation Noise Anderson, G
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Therefore, at Swiss airports, evenings and mornings were investigated for sleep disturbances by aircraft noise. This field study focuses on the sleep quality impact of aircraft noise at sleep onset in the evening and before wakeup in the morning.
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With respect to using long-term average noise levels, the report concludes, "The failure of analyses based on ‘entire night' noise measurements (that is, total noise exposure from retiring to last awakening) to account for appreciable variance in the awakening data indicates that cumulative noise exposure metrics such as DNL are ill-suited to prediction of noise-induced sleep disturbance." Importantly, this study also concludes that, cumulative .
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The two major sections of this report address sleep disturbance and hearing loss resulting from aircraft noise exposure. The report includes a comprehensive review of noise-induced sleep disturbance studies.
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From page 52... ...
of the variance in the relationship between noise exposure and sleep disturbance. It is nonetheless apparent in the studied circumstances of residential exposure that sleep disturbance effects of night-time aircraft noise intrusions are not dramatic on a per-event basis, and that linkages between outdoor aircraft noise exposure and sleep disturbance are tenuous.
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From page 53... ...
The WHO guidelines conclude, It is usually possible to express the relationship between noise levels and speech intelligibility in a single diagram, based on the following assumptions and empirical observations, and for speaker-to-listener distance of about 1 m: a. Speech in relaxed conversation is 100% intelligible in background noise levels of about 35 dBA, and can be understood fairly well in background levels of 45 dBA.
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. some degree of indoor speech interference would be expected whenever exterior noise levels exceed 75 dB to 85 dB (windows open and closed, respectively)
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Children within high-noise areas showed evidence of poor persistence on challenging tasks, and reported considerable annoyance with community noise levels, adjusted for individual differences in rating criteria for annoyance judgments. The data, collected around Munich International Airport and in a quiet urban Munich neighborhood, showed the dynamic range of noise exposures of approximately 9 dBA (24-h Leq of 68 dBA near the airport and 59 dBA not near the airport)
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From page 56... ...
Overall, there was a strong noise effect on recall, and a smaller but significant effect on recognition. From a sound source located in the classroom, the single-source studies, aircraft, and road traffic impaired recall at both noise levels, yet train noise and verbal noise did not affect recognition or recall.
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In that study, noise levels of 68 dBA Leq had a pronounced effect, whereas at 59 dBA Leq the effects were small. In other crosssectional studies effects were identified for outdoor noise exposures as low as 35 dBA Leq.
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From page 58... ...
This binary definition of noise exposure makes the task of defining a doseresponse curve difficult. However, one can see that at noise levels below 60 dBA Leq the effect on school children is small, whereas at noise levels above 65 dBA Leq the effects are well-identified.
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From page 59... ...
The noise exposure identified in this report is a Leq 66 dBA for the school with aircraft noise and 57 dBA Leq for the school without aircraft noise. The 66 dBA Leq conflicts with the stated 63 dBA Leq in the previous study for the same school one year earlier.
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From page 60... ...
The results indicated that chronic aircraft noise exposure does not always lead to generalized cognitive effects but, rather, more selective cognitive impairments on difficult tests in children. Note that the outdoor noise exposures for the school with aircraft noise and the school without aircraft noise is a rather small dynamic range, 57 to 63 dBA Leq or 6 dBA, and that the observed effects were not evident at 57 dBA Leq.
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From page 61... ...
The report provided the 24-h Leq data that showed that the old airport had noise exposures as high as 68 dBA Leq with aircraft noise and as low as 55 dBA Leq without aircraft noise. At the new airport, the noise levels were as low as 53 dBA Leq before opening and 62 dBA Leq after opening.
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From page 62... ...
Although the order provides a broad structure for consideration of soundscape preservation in the park facilities planning process, it does not address specific noise level goals or specific programs. In 1994, the NPS provided a report to Congress with an extensive review of aircraft overflights of the national parks (National Park Service 1994)
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Preserving the natural quiet is a controversial topic and subject to congressional mandate. The FAA has developed specific analytical tools included as part of the most recent version of the INM for use in analyzing aviation noise impacts in national parks.
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National Parks Air Tour Management Act of 2000, 11 pp. This act requires the development of ATMP for national parks.
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conducted this study primarily because of concerns that noise from air tours over national parks could impair visitors' experiences and park resources. The report deals mostly with compliance and implementation issues and does not include guidelines on park noise levels or methods to measure the effects of overflight noise on parks.
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Equivalent noise levels (Leq) were measured at 303 points (each point measured during 3 min)
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From page 67... ...
The MSP studies suggested that lowfrequency-induced rattle can be described by measuring the sum of the maximum noise levels in the one-third octave bands between 25 Hz and 80 Hz. The recently completed low-frequency study done under the PARTNER/COE Transport Canada programs (Hodgdon et al.
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From page 68... ...
These findings were controversial and subject to critical review by FICAN (Federal Interagency Committee on Aviation Noise 2002) followed by response from the authors.
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"Such an improvement would require use of a complex structure (e.g., a brick wall with minimal openings toward the noise source, and/or an insulated cavity wall with separately supported interior and exterior cladding and multi-pane windows of limited size) ." Federal Interagency Committee on Aviation Noise, FICAN on the Findings of the Minneapolis–St.
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From page 70... ...
than "metrics specifically designed to quantify low-frequency noise impact" implies little about the ability of C-weighted noise levels to usefully predict the prevalence of annoyance among residents of neighborhoods near runway thresholds and sidelines." Fidell, S., L Silvati, K
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From page 71... ...
To evaluate nesting and non-nesting spotted owl responses to helicopter noise, the authors measured flush frequency, flush distance, alert behavior, response duration, prey delivery rates, female trips from the nest, and nest attentiveness during manipulated and nonmanipulated periods. The owls' responses were more correlated to distance from the noise source rather than the noise levels themselves.
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1970) Anatomical hearing damage; hearing loss Mouse Simulated sonic booms (Reinis 1976)
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Startle reaction; running Aquatic Mammals Beluga whale Boat traffic (Acoustical Society of America 1980) Easily displaced Pinnepeds Sonic booms (80–89 dBA SPL)
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(Jehl and Cooper 1980) Startle responses; flushed off nest Simulated sonic booms (155.6–145.5 dBA)
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on wall of tank (Blaxter and Hoss 1981) Startle responses Sheepshead Minnow/Longnose Killifish Tanks exposed to high noise levels (up to +30 dB/ub)
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From page 76... ...
Chain saws were included in our manipulations to increase experimental options and to facilitate comparative results. The authors analyzed stimulus events by measuring noise levels as un-weighted one-third-octave band levels, applying frequency weighting to the resultant spectra, and calculating the SEL for total sound energy and the 0.5-s equivalent maximum energy level (Leq max 0.5-s)
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Spotted owls did not flush when the SEL noise level for helicopters was less than or equal to 102 dBO (92 dBA) and the Leq level for chain saws was less than or equal to 59 dBO (46 dBA)
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summarized that "while an effect is observed it is considered an influence which is often offset by the advantages associated with ready access to the airport and employment opportunities." Still, "studies indicate that a one decibel change in cumulative airport noise exposure (in DNL) usually results in a 0.5% to 2% decrease in real estate value." Furthermore, "there seems to be a decline in the noise depreciation index over time.
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From page 79... ...
Although most studies concluded that aviation noise effects on property value range from some negative impacts to significant negative impacts, some studies combined airport noise and proximity and concluded that the net effect on property value was positive. Prospective homebuyers were at times not well-informed about the noise levels of aircraft operations near the property of interest.
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Because there was no change in actual aircraft operations at the time of this study, the impacts of a change in noise levels was not calculated. Although the announcement brought on much debate, "results of the research reveal that residential property values and associated volumes of sales in
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Meta-analysis was applied to the negative relationship between airport noise exposure and residential property values. About one-third of the estimates have not been previously reported in the literature or were not included in previous meta-analysis.
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From page 82... ...
One of the consequences of the complex way weather affects sound propagation is that noise models are limited to estimating noise levels for average conditions. For any given flyover the noise experienced at an observer location is the product of the aircraft noise level and the effect of the atmosphere on sound propagation.
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84 FIGURE A13 Atmospheric sound absorption as a function of temperature and humidity (Beranek, Noise and Vibration, McGraw-Hill 1981)
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From page 84... ...
Annotated Bibliography -- Effect of Meteorology on Aviation Noise Embleton, T., "Tutorial on Sound Propagation Outdoors," The Journal of the Acoustical Society of America, Vol.
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The noise models use noise data in the form of NPD curves. These are curves of noise level versus distance, with separate curves for each power setting.
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These examples are shown schematically in Figure A15. INM includes both effects in computing aircraft noise levels.
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From page 87... ...
The shielding calculations in INM Version 7 are based on the methodology implemented in FHWA's Traffic Noise Model. In 1994, NATO/CCMS issued a final report from the working groups identifying various modeling techniques used in different countries and describing issues associated with modeling topographic effects on aviation noise (NATO/CCMS 1994)
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From page 88... ...
The report identifies the various modeling techniques used in different countries and describes the issues associated with modeling topographic effects on aviation noise. Sample calculations and contours are presented.
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From page 89... ...
Low frequency noise with its related vibration, meteorological, and topological data continue to drive modeling improvements, and correct some limited under-predictions of sideline-noise levels. Home property values may have limited relationship to noise levels, and future research linked with powerful geographic information system tools may provide new insights.
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