Non-acoustical Factors Research Articles

Investigations on psychoacoustical and non-acoustical moderators for annoyance evoked by wind turbine noise

In 2012, in total around 23 000 wind turbines are installed on land in Germany. These wind turbines are important to achieve a change in Germany's current energy policy gaining more energy from renewable resources. However, current research underlines that the noise of wind turbines causes noise annoyance and provoke complaints. The sound characteristics of wind turbines depend on many different variables, e.g., type of wind turbine and wind speed. Unfortunately, only little is known about the specific noise characteristics, which are mainly responsible for noise annoyance. Therefore, laboratory experiments are carried out to identify the most annoying noise characteristics of wind turbine noise. The laboratory experiment includes an evaluation of different sounds from wind turbines, manipulated wind turbine sounds, and sounds from other noise sources. The work intends to improve the understanding about the role of psychoacoustic parameters going beyond equivalent continuous sound level. Additionally, the relevance of non-acoustical factors for annoyance caused by wind turbine noise is investigated by interviewing extensively the test subjects.

Railway noise annoyance: exposure-response relationships and testing a theoretical model by structural equation analysis.

In some regions the exposure to railway noise is extremely concentrated, which may lead to high residential annoyance. Nonacoustical factors contribute to these reactions, but there is limited evidence on the interrelations between the nonacoustical factors that influence railway noise annoyance. The aims of the present study were (1) to examine exposure-response relationships between long-term railway noise exposure and annoyance in a region severely affected by railway noise and (2) to determine a priori proposed interrelations between nonacoustical factors by structural equation analysis. Residents (n = 320) living close to railway tracks in the Middle Rhine Valley completed a socio-acoustic survey. Individual noise exposure levels were calculated by an acoustical simulation model for this area. The derived exposure-response relationships indicated considerably higher annoyance at the same noise exposure level than would have been predicted by the European Union standard curve, particularly for the night-time period. In the structural equation analysis, 72% of the variance in noise annoyance was explained by the noise exposure (L(den)) and nonacoustical variables. The model provides insights into several causal mechanisms underlying the formation of railway noise annoyance considering indirect and reciprocal effects. The concern about harmful effects of railway noise and railway traffic, the perceived control and coping capacity, and the individual noise sensitivity were the most important factors that influence noise annoyance. All effects of the nonacoustical factors on annoyance were mediated by the perceived control and coping capacity and additionally proposed indirect effects of the theoretical model were supported by the data.

Annoyance and self-reported sleep disturbance due to night-time railway noise examined in the field

Railway noise interferes with daytime activities and disturbs sleep leading to annoyance of exposed residents. The main objective of this paper was to establish exposure-response relationships between nocturnal railway noise exposure and annoyance and to examine self-reported sleep disturbances as short-term reactions to noise. In a field study 33 residents living close to railway tracks in the Cologne/Bonn area (Germany) were investigated. Railway noise was measured indoors during nine consecutive nights at each site. Questionnaires referring to annoyance and non-acoustical factors were performed. Annoyance ratings increased significantly with the total number of trains and freight trains per night, and non-significantly with rising number of passenger trains and energy equivalent sound pressure level (L(Aeq)), when adjusting the model for non-acoustical variables. The total number of trains and the number of freight trains also significantly affected self-reported awakening frequency, but no other aspects of subjective sleep disturbances. The responses of this subject sample referring to railway noise in the previous night point to rather low impairments of exposed residents.

The application of a notice-event model to improve classical exposure-annoyance estimation

Sound perception of humans is determined by a variety of factors such as intensity, frequency, temporal structure, masking and localization. Furthermore, a wide range of non-acoustical factors determine whether certain sounds are perceived as annoying. However, classical exposure-response determination for the assessment of annoyance and health effects is based on average sound levels - sometimes with applied penalties for evening and night noise (Lden). A research collaboration between Ghent University and the Medical University Innsbruck focuses on the improvement of exposure-annoyance modeling by including characteristics of the temporal structure and the attention of the involved human subjects. The basis for this work is the developed “notice-event-model” (De Coensel B et al. 2009). Intensive traffic modeling as input for extended individual noise mapping per dwelling allows to test the additional impact by the inclusion of derived acoustical indicators of the temporal pattern (Fluctuation, emergence) of the main sources (highway, main road, railway) and the human activity pattern to accommodate for masking and habituation (e.g. Notice Sound Exposure Level, notice time). This improved exposure assessment is compared with the existing classical exposure-response information from two large-scale surveys in Austrian alpine valleys. The results show that this approach is promising - but further development is needed.

Noise annoyance from industrial and road traffic combined noises: A survey and a total annoyance model comparison

The literature on noise annoyance emphasizes that acoustical factors cannot totally explain the annoyance felt by a population exposed to community noises, and that some non-acoustical factors have an effect on annoyance. This research paper deals with the annoyance caused by combined noises coming from road traffic and an industrial site. This type of combination has been very little studied to date. An in situ study was conducted in an area of a French town exposed to these two noise sources. To investigate the annoyance caused by these combined noises, the work involved both a mapping of the industrial and road traffic noises present in the survey area and a questionnaire designed to evaluate the noise annoyance experienced by residents and to identify the factors that probably influence noise annoyance. The results highlight the link between the noise levels measured and the annoyance felt by the respondents. They also show that certain non-acoustical factors have an impact on annoyance felt. Indeed, the results highlight a positive correlation between fear of industrial sites and the annoyance expressed. They also show correlations between some items to evaluate noise sensitivity and the annoyance expressed. No significant correlation has been found between annoyance and the other non-acoustical factors such as age, sex and length of residence. Finally, several total annoyance models were tested for this noise combination. Two of them, namely the strongest component model and a proposed perceptual version of the mixed model, were able to better predict total annoyance than the other tested models.

THE ROLE OF NON-ACOUSTICAL FACTORS IN NOISE ANNOYANCE OF URBAN POPULATION

Background and Aims: Noise annoyance is influenced by acoustical factors, such as type of noise, noise levels and frequency, and non-acoustical factors, including physiological, psychological and social factors. The aim of this study was to assess the role of some non-acoustical factors in noise annoyance of urban population. Methods: A cross-sectional study was performed on 1311 adults (452 men and 679 women), aged 42±16 years, residing in noisy urban areas in Belgrade for more than one year. Non-acoustical factors, such as socio-economic status (family income, education and employment) and dwelling characteristics (apartment size, floor level, orientation of windows) were estimated using a questionnaire. Noise annoyance was estimated using self-reported 5-graded verbal annoyance scale. Based on their annoyance level, participants were divided into two groups: highly annoyed (high level of noise annoyance) and less annoyed (low to moderate level of annoyance). Results: Highly annoyed participants were more likely to be females, married with children and to have higher family income. Educational level and employment were similarly distributed among highly annoyed and less annoyed subjects. Highly annoyed participants were more likely to be living on lower floor levels (on the ground floor, basement or first floor), for a longer period of time, to spend more time indoors, and to have windows of their bedrooms facing the street. Orientation of windows toward the street was the most important predictor of noise annoyance (B=2.690, 95% Confidence Interval =1.796-4.029), followed by the living on the groundfloor or first floor (B=1,448, 95% CI =1.134-1.851), independently from age, gender and noise exposure. Conclusions: Our study identified several non-acoustical factors as indicators of noise annoyance, independent from age, gender and noise exposure, primarily some dwelling characteristics and time spent indoors. Socio-economic status was not related with noise annoyance, when all the relevant parameters were taken into account.

The effects of long-term exposure to railway and road traffic noise on subjective sleep disturbance

The exposure-response relationships between subjective annoyance with sleep disturbance from railway trains and road traffic noise were established from an extensive social survey by CENVR (Center for Environmental Noise and Vibration Research) in Korea. The objectives of this research are to determine the long-term effects of noise on sleep and to compare the exposure-response relationships from different noise sources with those from other studies and to elucidate the effects of some modifying factors on subjective responses to noise. From an investigation of the percentage of a highly sleep-disturbed population (%HSD) in response to railway and road traffic noise, it was found that sleep is affected more by railway noise than by road traffic noise. The effects of non-acoustical factors on the responses were examined and sensitivity was shown to be a significant modifying factor, as it pertains to subjective sleep disturbance. A comparison of the response curves from an analysis of pooled data from predominantly European surveys by Miedema and Vos [Behav. Sleep Med. 5, 1-20 (2007)] with the response curves from this survey showed more of a subjective sleep disturbance response in this survey to railway noise, whereas there was no significant difference in terms of a response to road traffic noise.

Policy discourse, people’s internal frames, and declared aircraft noise annoyance: An application of Q-methodology

Aircraft noise annoyance is studied extensively, but often without an explicit theoretical framework. In this article, a social approach for noise annoyance is proposed. The idea that aircraft noise is meaningful to people within a socially produced discourse is assumed and tested. More particularly, it is expected that the noise policy discourse influences people's assessment of aircraft noise. To this end, Q-methodology is used, which, to the best of the authors' knowledge, has not been used for aircraft noise annoyance so far. Through factor analysis five distinct frames are revealed: "Long live aviation!," "aviation: an ecological threat," "aviation and the environment: a solvable problem," "aircraft noise: not a problem," and "aviation: a local problem." It is shown that the former three frames are clearly related to the policy discourse. Based on this observation it is argued that policy making is a possible mechanism through which the sound of aircraft is turned into annoyance. In addition, it is concluded that the experience of aircraft noise and, in particular, noise annoyance is part of coherent frames of mind, which consist of mutually reinforcing positions and include non-acoustical factors.

Testing a theory of aircraft noise annoyance: A structural equation analysis

Previous research has stressed the relevance of nonacoustical factors in the perception of aircraft noise. However, it is largely empirically driven and lacks a sound theoretical basis. In this paper, a theoretical model which explains noise annoyance based on the psychological stress theory is empirically tested. The model is estimated by applying structural equation modeling based on data from residents living in the vicinity of Amsterdam Airport Schiphol in The Netherlands. The model provides a good model fit and indicates that concern about the negative health effects of noise and pollution, perceived disturbance, and perceived control and coping capacity are the most important variables that explain noise annoyance. Furthermore, the model provides evidence for the existence of two reciprocal relationships between (1) perceived disturbance and noise annoyance and (2) perceived control and coping capacity and noise annoyance. Lastly, the model yielded two unexpected results. Firstly, the variables noise sensitivity and fear related to the noise source were unable to explain additional variance in the endogenous variables of the model and were therefore excluded from the model. And secondly, the size of the total effect of noise exposure on noise annoyance was relatively small. The paper concludes with some recommended directions for further research.

ANNOYANCE FROM ROAD TRAFFIC NOISE: A REVIEW

In this paper the negative effects resulting from exposure to road traffic noise on people's well being is reviewed in the light of the latest published findings. Annoyance is particularly focused on, which is considered to be one of the first and most widespread reactions to environmental noise. The nonauditory effects of noise on humans are viewed as being generally stress-related, following observations that noise exposures engender physiological reactions typical to those of stress. First, a short presentation is made of what noise in general is. Subsequently, in order to assess some subjective judgements of noise, some of the important noise descriptors, which are often used to quantify various aspects of road traffic noise are introduced. In general terms, it is found from the present review that the continuous exposure of people to road traffic noise leads to suffering from various kinds of discomfort, thus reducing appreciably the number of their well-being elements. Drawing such a conclusion is hindered by difficulties when nonacoustical factors, for instance socio-economic situation, age and gender, are also taken into account along with the usual acoustical factors of road traffic noise. One of people's first and direct reactions to noise is in terms of annoyance. The results of several decades of research on this topic have permitted lately the establishment of a more or less quantitative relationship between the objective quantities characterizing road traffic noise and the human subjective reaction to it as expressed by annoyance. These findings are important at both the society and the individual level, in as much as they may help in regulating in a more efficient way the planning of road traffic activity in order to secure at least the minimum of comfort to the affected population.

Noise exposure and public health.

Exposure to noise constitutes a health risk. There is sufficient scientific evidence that noise exposure can induce hearing impairment, hypertension and ischemic heart disease, annoyance, sleep disturbance, and decreased school performance. For other effects such as changes in the immune system and birth defects, the evidence is limited. Most public health impacts of noise were already identified in the 1960s and noise abatement is less of a scientific but primarily a policy problem. A subject for further research is the elucidation of the mechanisms underlying noise-induced cardiovascular disorders and the relationship of noise with annoyance and nonacoustical factors modifying health outcomes. A high priority study subject is the effects of noise on children, including cognitive effects and their reversibility. Noise exposure is on the increase, especially in the general living environment, both in industrialized nations and in developing world regions. This implies that in the twenty-first century noise exposure will still be a major public health problem.

Review of the effects of noise on performance

The effects of noise on job performance are not as easily discerned and predictable as other effects, such as those on hearing or speech communication. The extent to which noise affects performance depends on numerous nonacoustical factors, such as the subject's biological and psychological state, as well as certain external factors. Despite these and other difficulties involved in comparing research results, a recent review of the noise and performance literature provides sufficient evidence to indicate adverse effects under certain circumstances. The probability of performance decrements increases with increased (1) noise level, (2) intermittency, (3) aperiodicity, (4) lack of controllability. (5) task complexity, (6) task duration, and (7) the addition of certain other stressors. The review was sponsored by the U.S. Army Human Engineering Laboratory, and performed under the auspices of Gallaudet University.

Experiments to assess musical instrument quality

Work in progress, supported by the Science Research Council, on the transient behavior of trombones and its possible relation to quality is described. The approach is along three paths: (a) a measurement of the input impedance firstly in the steady state and then in the transient state; (b) a study of the basic fluid dynamics of the system to examine the significance of the effects of microturbulence, boundary-layer fluctuations, etc. on the starting transient; (c) a psychological study of the decision processes employed by players and listeners and the subjective magnitudes involved when assessing instrument quality. Although only very preliminary indications are to hand, approach (c) is beginning to seem the most useful and data obtained in respect of other instruments also indicate that nonacoustical factors may be paramount in determining the overall judgment of the musical quality of an instrument. For example, according to our first investigations, the most important attribute of a trombone seems to be the mechanical behavior of the slide.

Intelligibility of Words in Sentences

Acoustical and nonacoustical factors have been observed which suggest that words in one position in a sentence may be more intelligible than words in other positions. An experiment was undertaken to determine the effect of some of these factors upon word intelligibility in sentences heard in noise. One-hundred six-word sentences, drawn from magazines, were read to 10 listeners The intelligibility of words in the first, fourth, and sixth positions was determined and their acoustic characteristics were measured. Measurements of intensity, duration, and total energy were obtained for each word. The words in final position were lowest in intelligibility despite the fact that they were highest in average intensity, duration, and energy. This apparent contradiction was resolved by a grammatical analysis of the words. The words in the final position included a larger proportion of content words (Nouns, verbs, adjectives, adverbs) than words in the other positions. The content words are less predictable, less intelligible, and contain more information per word than pronouns and function words (articles, prepositions, conjunctions). The intelligibility observed at each position was approximately equal to the intelligibility calculated from (1) the intelligibilities of content and function words, irrespective of position, and (2) the relative proportions of content and function words.