Aviation Noise Impacts: State Of The Science
Noise Health. 2017 Mar-Apr; 19(87): 41–50.PMCID: PMC5437751doi: 10.4103/nah.NAH 104 16PMID: 29192612Aviation Noise Impacts: State of the ScienceMathias Basner, MD, PhD, MSc,1 Charlotte Clark,2 Anna Hansell,3,4 James I. Hileman,5 Sabine Janssen,6Kevin Shepherd,7 and Victor Sparrow81Unit for Experimental Psychiatry, Division of Sleep and Chronobiology, University of Pennsylvania PerelmanSchool of Medicine, Philadelphia, PA, USA2Centre for Psychiatry, Barts & The London School of Medicine, Queen Mary University of London, London, UnitedKingdom3MRC-PHE Centre for Environment and Health, Department of Epidemiology and Biostatistics, School of PublicHealth, Faculty of Medicine, Imperial College London, London, United Kingdom4Public Health and Primary Care, Imperial College Healthcare NHS Trust, St. Mary’s Hospital, London, UnitedKingdom5Office of Environment and Energy (AEE-3), Federal Aviation Administration, Washington, DC, USA6Urban Environment and Safety, TNO (Netherlands Organization for Applied Scientific Research), Delft, TheNetherlands7M.S. 463 Structural Acoustics Branch, NASA Langley Research Center, Hampton, VA8Penn State, University Park, PA, USAAddress for correspondence: Mathias Basner, Associate Professor of Sleep and Chronobiology in Psychiatry,Unit for Experimental Psychiatry, Division of Sleep and Chronobiology, University of Pennsylvania Perelman Schoolof Medicine, 1019 Blockley Hall, 423 Guardian Drive, Philadelphia, PA 19104-6021, USA. E-mail:basner@upenn.eduCopyright : 2017 Noise & HealthThis is an open access article distributed under the terms of the Creative Commons Attribution-NonCommercialShareAlike 3.0 License, which allows others to remix, tweak, and build upon the work non-commercially, as long as theauthor is credited and the new creations are licensed under the identical terms.AbstractNoise is defined as “unwanted sound.” Aircraft noise is one, if not the most detrimental environmentaleffect of aviation. It can cause community annoyance, disrupt sleep, adversely affect academicperformance of children, and could increase the risk for cardiovascular disease of people living in thevicinity of airports. In some airports, noise constrains air traffic growth. This consensus paper wasprepared by the Impacts of Science Group of the Committee for Aviation Environmental Protection ofthe International Civil Aviation Organization and summarizes the state of the science of noise effectsresearch in the areas of noise measurement and prediction, community annoyance, children’s learning,sleep disturbance, and health. It also briefly discusses civilian supersonic aircraft as a future source ofaviation noise.
Keywords: Aircraft, annoyance, health, noise, performance, sleepINTRODUCTIONPurposeThe goal of this review is to briefly summarize the current state of scientific knowledge regarding theadverse effects of aircraft noise emissions on the public. Every effort has been made to base thefindings upon peer-reviewed publications, carefully reviewed by specialists from around the world.The topics addressed here are community annoyance, children’s learning, sleep disturbance, healthimpacts, and the noise of supersonic aircraft. Appendix A additionally provides some backgroundinformation on noise measurement and prediction as well as technical definitions for the interestedreader.Task of the panelAircraft noise discussions can be very emotional, and politicians and legislators often struggle to definelimit values that both protect the population against the adverse effects of aircraft noise but do notrestrict the positive societal effects of air traffic. Noise effects researchers have an important advisoryrole. They derive so-called exposure–response functions that allow health impact assessments and,therefore, inform political decision-making. The efforts of the Noise Panel were directed at assessingthe current state of the science and provide contracting states with a brief overview of the impacts ofaircraft noise on communities. This white paper constitutes a consensus among its authors, who haveconsiderable experience in noise effects research, and is based on input from an international expertpanel workshop held on February 10 and 11, 2015 in Alexandria, VA, USA. Noise effects depend,among others, on housing structure and cultural values, and legislation and limit values accordinglydiffer considerably between contracting states. Therefore, the authors did not try to suggest specificlimit values, but rather pointed to existing exposure–response functions and recommendations ofinternational organizations.COMMUNITY ANNOYANCEDefinition of community annoyanceCommunity annoyance refers to the average evaluation of the disturbing aspects or nuisance of a noisesituation by a “community” or group of residents, combined in a single outcome, annoyance. Tofacilitate inter-study comparisons and data pooling for the development of exposure–responserelationships, a standardized annoyance question has been proposed by members of the InternationalCommission on Biological Effects of Noise,[1] and was adopted by ISO TS 15666.[2] The percentageof highly annoyed respondents is considered to be the main indicator of community annoyance. Theuse of a common question allows for the comparison of studies from around the globe. As such, theImpacts of Science Group (ISG) encourages states to utilize the ISO TS 15666 survey in their efforts tomeasure and understand community annoyance.Moderating non-acoustic variablesIndividual annoyance scores are not only related to acoustic variables, but can be importantlymoderated by several personal and situational variables. Two meta-analyses on the influence of suchnon-acoustical factors on annoyance showed the largest effects of age, fear, and noise sensitivity.[3,4]
Additional moderating variables put forward are beliefs on the necessity of the noise source, the abilityto somehow control or cope with noise or its consequences, trust in authorities, and previousexperience with or future expectations regarding noise.[5,6]Exposure–response relationshipsOver the years, several attempts have been made to relate the percentage of respondents highlyannoyed by a given source to the day–night average noise exposure level LDN. The derivation ofexposure–response curves based on data from many individual studies[7] yielded different curves foraircraft, road traffic, and railway noise, with higher annoyance for aircraft noise than for road traffic orrailway noise at the same exposure level. However, there is evidence that the annoyance response toaircraft noise has even increased over the years, and that exposure–response curves based on olderaircraft noise annoyance data may no longer apply.[8,9] This stresses the need for an update based onmore recent studies using standardized methods.(Inter)national versus local exposure–response relationshipsWhile exposure–response relationships have been recommended for assessing the expected annoyanceresponse in noise situations, they are not applicable to assess the short-term effects of a change in noiseclimate. There are indications for a temporary overshoot in annoyance response in situations with ahigh rate of change, for instance, where a new runway is opened.[10,11] In addition, in more or lesssteady state situations, the annoyance response in specific surveys often differs from the averageexpected response.[12] Since airports and communities may differ greatly in several variablesmoderating annoyance, local exposure–response relationships, if available, may be preferred forpredicting annoyance. Still, exposure–response relationships describing the average annoyanceresponse are required to allow health impact assessment across communities and to establish preferablelimit values for levels of aircraft noise.Complaints and their relationship to noise and noise effectsMany airports receive and log complaints as a part of their noise monitoring and community outreachefforts. Complaints seem to be triggered by unusual events (e.g., louder than normal; unusual aircraftground track or altitude) and operational changes (changes in runway usage or flight tracks).Annoyance and complaints are different phenomena, the first being a privately held opinion, and thelatter being an overt action. Relatively few studies have utilized complaints databases to investigatewhether complaints are related to long-term annoyance as measured using social surveys. Rather thanmonitoring the number of callers, which may be distorted by repeat callers, this approach shouldpreferably be based on the number of individual complainants and the number of specific issues orincidents that cause complaints. There is, however, evidence to suggest that complainants do notrepresent a cross-section of the population at large, both in terms of their demographic characteristicsand their annoyance.Supplementary noise metricsAn important question for aircraft noise annoyance is whether the annoyance due to infrequent highlevels of noise events is the same as the annoyance caused by frequent moderate levels at the same LDN. While some data suggest that the trade-off between levels and numbers of overflights in L Aeqbased metrics such as L DN is approximately correct for predicting the noise annoyance,[13] there are
also data suggesting that a higher weight of the number of flights might be appropriate.[14] However,an examination of 10 airport surveys did not support a weighting of “number” greater than thatimplicit in L Aeq.[15] On average, the weighting was less than that.Noise mitigationAnnoyance due to aircraft noise has been recognized by authorities and policy makers as a harmfuleffect that should be prevented and reduced. Priority is given to noise reduction at the source (e.g.,engine noise, aerodynamic noise) and reducing noise by adjusting take-off and landing procedures, butthese measures are not always sufficient or feasible. Sound insulation of dwellings is often applied, butmay not reduce annoyance levels when it is associated with poor indoor air quality.[16] In addition, theobserved influence on annoyance of several non-acoustical factors such as fear, perceived control, andtrust in authorities suggests that communication strategies addressing these issues could stronglycontribute to the reduction of annoyance, alongside or even in the absence of a noise reduction.ConclusionsThere is substantial evidence that aircraft noise exposure is associated with annoyance indicators, andexposure–response relationships have been derived to estimate the expected percentage of highlyannoyed persons at a community level. Still, several personal and situational factors importantly affectthe annoyance of individuals. Recent evidence for an increase in the annoyance response at a givenexposure level indicates the need for updating exposure–response curves based on recent studies usingharmonized methods, as well as verifying the circumstances leading to a heightened communityresponse. This could inform political decision-making on managing aircraft noise exposure and onmitigation measures.CHILDREN’S LEARNINGChronic aircraft noise exposure and children’s learningRecent reviews of how noise, and in particular aircraft noise, affect children’s learning have concludedthat aircraft noise exposure at school or at home is associated with children having poorer reading andmemory skills.[17] There is also an increasing evidence base which suggests that children exposed tochronic aircraft noise at school have poorer performance on standardized achievement tests, comparedwith children who are not exposed to aircraft noise. In the limited space available here, it is onlypossible to discuss some of the central epidemiological field studies forming the empirical basis ofthese conclusions. The most recent large scale cross-sectional study, the RANCH study (Road trafficand Aircraft Noise and children’s Cognition & Health), of 2844 children aged 9–10 years from 89schools around London Heathrow, Amsterdam Schiphol, and Madrid Barajas airports found exposure–response associations between aircraft noise and poorer reading comprehension and poorer recognitionmemory, after taking social position and road traffic noise, into account.[18] Reading comprehensionbegan to fall below average at around 55 dB L Aeq,16hours at school, but as the association was linear,there is no specific threshold above which noise effects begin, and any reduction in aircraft noiseexposure should lead to an improvement in reading comprehension. A 5 dB increase in aircraft noiseexposure was associated with a 2 month delay in reading age in the UK, and a 1-month delay in theNetherlands.[19] These associations were not explained by air pollution.[20] Children’s aircraft noiseexposure at school and that at home are often highly correlated. In the RANCH study, night-time
aircraft noise at the child’s home was also associated with impaired reading comprehension andrecognition memory, but night-noise did not have an additional effect to that of daytime noise exposureon reading comprehension or recognition memory.[21]Interventions to reduce aircraft noise exposure at schoolStudies have shown that interventions to reduce aircraft noise exposure at school do improve children’slearning outcomes. The longitudinal, prospective Munich Airport study[22] found that prior to therelocation of the airport in Munich, high noise exposure was associated with poorer long-term memoryand reading comprehension in children aged 10 years. Two years after the airport was closed, thesecognitive impairments were no longer present, suggesting that the effects of aircraft noise on cognitiveperformance may be reversible if the noise stops. In the cohort of children living near the newly openedMunich airport, impairments in memory and reading developed over the 2-year period. This studysuggests that it takes a couple of years for impairments to develop. A cross-sectional study of 6000schools exposed between the years 2000–2009 at the top 46 United States airports (exposed to day–night-average sound level of 55 dB or higher) found significant associations between aircraft noise andstandardized tests of mathematics and reading, after taking demographic and school factors intoaccount.[23] In a sub-sample of 119 schools, it was found that the effect of aircraft noise on children’slearning disappeared once the school had sound insulation installed. These studies suggest thatinsulation of schools yields improvements in children’s learning.Mechanisms linking chronic aircraft noise exposure and learningAircraft noise may directly affect the development of cognitive skills such as reading and memory, buta range of pathways and mechanisms for the effects have also been proposed. Effects might beaccounted for by communication difficulties, teacher and pupil frustration, reduced morale, impairedattention, increased arousal which influences task performance, and sleep disturbance from homeexposure which might cause performance effects the next day.[24,25] Noise causes annoyance,particularly if an individual feels their activities are being disturbed or if it causes difficulties withcommunication. In some individuals, annoyance responses may result in physiological andpsychological stress responses, which might explain poorer learning outcomes.Guidelines for children’s noise exposure at schoolThe World Health Organization (WHO) Community Noise Guidelines[26] suggest that the backgroundsound pressure level (SPL) in school classrooms should not exceed 35 dB L Aeq during teachingsessions to protect from speech intelligibility and disturbance of information extraction. The WHOguidelines also suggest that school’s outdoor playgrounds should not exceed 55 dB L Aeq during therecess period, to protect from annoyance. The American National Standards Institute (ANSI) Standardfor School Acoustics (ANSI S12.50-2002/2010), suggests that internal background noise forunoccupied classrooms should be 35 dB L Aeq. The ANSI standard is supported by the AcousticalSociety of America and INCE-USA. While the WHO and the ANSI guidelines both specify amaximum sound level of 35 dB for classrooms, it should be noted that for ANSI guidelines, this is forunoccupied classrooms, whereas for the WHO guidelines, this is for occupied classrooms. It shouldalso be noted that WHO included cognitive impairment of children as one end-point in theirpublication on Burden of Disease from Environmental Noise Quantification of healthy life years lostin Europe,[27] relying mainly on the results from the Munich study and the RANCH study.
ConclusionsThere is sufficient evidence for a negative effect of aircraft noise exposure on children’s cognitiveskills such as reading and memory, as well as on standardized academic test scores. Evidence is alsoemerging to support the insulation of schools that may be exposed to high levels of aircraft noise. Arange of plausible mechanisms have been proposed to account for aircraft noise effects on children’slearning. Further knowledge about exposure–effect relationships in different contexts would furtherinform decision-making. It may also be informative to derive relationships for a range of additionalnoise exposure metrics, such as the number of noise events. To date, few studies have evaluated theeffects of persistent aircraft noise exposure throughout the child’s education, and there remains a needfor longitudinal studies of aircraft noise exposure at school and educational outcomes.SLEEP DISTURBANCESleep and its importance for healthSleep is a biological imperative, and a very active process that serves several vital functions.Undisturbed sleep of sufficient length is essential for daytime alertness and performance, quality oflife, and health.[27,28] The epidemiologic evidence that chronically disturbed or curtailed sleep isassociated with negative health outcomes (such as obesity, diabetes, and high blood pressure) isoverwhelming. For these reasons, noise-induced sleep disturbance is considered the most deleteriousnon-auditory effect of environmental noise exposure.Aircraft noise effects on sleepThe auditory system has a watchman function and constantly scans the environment for potentialthreats. Humans perceive, evaluate, and react to environmental sounds while asleep.[29] At the sameSPL, meaningful or potentially harmful noise events are more likely to cause arousals from sleep thanless meaningful events. As aircraft noise is intermittent noise, its effects on sleep are primarilydetermined by the number and acoustical properties (e.g., maximum SPL, spectral composition) ofsingle noise events. However, whether or not noise will disturb sleep also depends on situational (e.g.,sleep depth)[30] and individual (e.g., noise sensitivity) moderators.[29] Sensitivity to nocturnal noiseexposure varies considerably between individuals. The elderly, children, shift-workers, and those whoare ill are considered at risk for noise-induced sleep disturbance.[28] Repeated noise-induced arousalsimpair sleep quality through changes in sleep structure including delayed sleep onset and earlyawakenings, less deep (slow wave) and rapid eye movement (REM) sleep, and more time spent awakeand in superficial sleep stages.[30,31] Both deep and REM sleep have been shown to be important forsleep recuperation in general and memory consolidation specifically. Non-acoustic factors (e.g., hightemperature, nightmares) can also disturb sleep and complicate the unequivocal attribution of arousalsto noise.[32] Field studies in the vicinity of airports have shown that most arousals cannot be attributedto aircraft noise, and noise-induced sleep-disturbance is in general less severe than that observed inclinical sleep disorders such as obstructive sleep apnea.[33] Short-term effects of noise-induced sleepdisturbance include impaired mood, subjectively and objectively increased daytime sleepiness, andimpaired cognit
Office of Environment and Energy (AEE-3), Federal Aviation Administration, Washington, DC, USA Urban Environment and Safety, TNO (Netherlands Organization for Applied Scientific Research), Delft, The Netherlands M.S. 463 Structural Acoustics Branch, NASA Langley Research Center, Hampton, VA Penn State, University Park, PA, USA
Noise Figure Overview of Noise Measurement Methods 4 White Paper Noise Measurements The noise contribution from circuit elements is usually defined in terms of noise figure, noise factor or noise temperature. These are terms that quantify the amount of noise that a circuit element adds to a signal.
Federal Aviation Administration. Research Areas on Noise Impacts Annoyance - In 2014, FAA initiated a national survey to measure public annoyance to aircraft noise, as part of FAA's broader research portfolio related to aircraft noise - Responses from over 10,000 people living near 20 U.S. airports were collected
The Noise Element of a General Plan is a tool for including noise control in the planning process in order to maintain compatible land use with environmental noise levels. This Noise Element identifies noise sensitive land uses and noise sources, and defines areas of noise impact for the purpose of
7 LNA Metrics: Noise Figure Noise factor is defined by the ratio of output SNR and input SNR. Noise figure is the dB form of noise factor. Noise figure shows the degradation of signal's SNR due to the circuits that the signal passes. Noise factor of cascaded system: LNA's noise factor directly appears in the total noise factor of the system.
noise and tire noise. The contribution rate of tire noise is high when the vehicle is running at a constant speed of 50 km/h, reaching 86-100%, indicating tire noise is the main noise source [1]. Therefore, reducing tire noise is important for reducing the overall noise of the vehicle and controlling noise pollution [2].
Figure 1: Power spectral density of white noise overlaid by flicker noise. Figure 2: Flicker noise generated from white noise. 1.1 The nature of flicker noise Looking at processes generating flicker noise in the time domain instead of the frequency domain gives us much more insight into the nature of flicker noise.
Measuring aviation noise - the methodology behind measuring, assessing and describing noise is important context in this area, so this chapter provides background on how aviation noise is measured, in the UK and Europe, and its effects on people. Quieter aircraft design - this chapter reviews the significant advances
the noise figure of the receiver. Noise figure has nothing to do with modulation or demodula-tion. It is independent of the modulation format and of the fidelity of modulators and demodulators. Noise figure is, therefore, a more general concept than noise-quieting used to indicate the sensitivity of FM receivers or BER used in digital .
