Showing papers in "Noise & Health in 2002"

The noise/stress concept, risk assessment and research needs

Abstract: In principle, the noise/stress hypothesis is well understood: Noise activates the pituitary-adrenal-cortical axis and the sympathetic-adrenal-medullary axis. Changes in stress hormones including epinephrine, norepinephrine and cortisol are frequently found in acute and chronic noise experiments. The catecholamines and steroid hormones affect the organism's metabolism. Cardiovascular disorders are especially in focus for epidemiological studies on adverse noise effects. However, not all biologically notifiable effects are of clinical relevance. The relative importance and significance of health outcomes to be assessed in epidemiological noise studies follow a hierarchical order, i.e. changes in physiological stress indicators, increase in biological risk factors, increase of the prevalence or incidence of diseases, premature death. Decision-making and risk management rely on quantitative risk assessment. Epidemiological methods are the primary tool for providing the necessary information. However, the statistical evidence of findings from individual studies is often weak. Magnitude of effect, dose-response relationship, biological plausibility and consistency of findings among studies are issues of epidemiological reasoning. Noise policy largely depends on considerations about cost-effectiveness, which may vary between populations. Limit or guideline values have to be set within the range between social and physical well-being - between nuisance and health. The cardiovascular risk is a key-outcome in non-auditory noise effects' research because of the high prevalence of related diseases in our communities. Specific studies regarding critical groups, different noise-sources, day/evening/night comparisons, coping styles and other effect-modifying factors, and the role of annoyance as a mediator of effect are issues for future research in this field.

Chronic Cortisol Increases in the First Half of the Night Caused by Road Traffic Noise.

Abstract: 56 children age 7 - 10 had a medical check-up and they and their mothers completed questionnaires. Additionally the children's excretion of free cortisol was measured by HPLC in two urine samples collected at 1 p.m. and in the morning. The children lived either at a busy road with 24 h lorry traffic or in quiet areas. At the side of the road the noise level was registered during five nights. In the bedrooms representative measurements of the short-term maximal sound level (L(Amax) and L(Cmax)) and of the frequency spectrum were taken. During the night on average every 2 minutes a lorry with L(max) > 80 dB(A) passed by the houses. The indoor levels of the higher exposed half of the children were L(max) = 33-52 dB(A) resp. 55-78dB(C)). The frequency spectrum had its maximum below 100 Hz. 74% of the higher exposed never opened their windows as compared to 25% in the lower exposed half group. The excretion of free cortisol and its metabolites in the first half of the night was significantly correlated to L(Cmax) (co-variables: age, sex, and the day of the week) as well as to impaired sleep, memory and ability to concentrate. The cortisol excretion in the second half of the night was not correlated to the noise level. Disturbances of the normal circadian rhythm of cortisol can be quantified by the quotient of the cortisol excretion in the first half of the night in relation to that in the second half. Children under long-term road traffic noise exposure during the night had an increased risk of chronic stress hormone regulation disturbances. These disturbances were significantly correlated to L(Cmax) and findings of allergy and/or asthma bronchial. Long-term low frequency noise exposure with Lmax < 55 dB(A) during the night resulted in chronic increases of children's excretion of free cortisol in the first half of the night and in serious disturbances of the circadian rhythm of cortisol. Indications of increased risks of asthma bronchial and allergies in noise exposed children with stress hormone regulation disturbances need further clarification

Annoyance Caused by Exposure to Road Traffic Noise: An Update.

Abstract: This paper addresses the negative effects resulting from the exposure to road traffic noise on people's well being with a focus on annoyance. Following the observations that noise exposures engender physiological reactions typical of stress, the non-auditory effects of noise on humans are generally viewed as being stress-related, and annoyance is one of the first and most direct reactions to environmental noise. In general terms, it is found 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. However drawing such a conclusion is hindered by difficulties when non-acoustical factors like sensitivity, socio-economic situation and age are also taken into account along with the usual acoustical factors of road traffic noise. The results of several decades of research on this topic have permitted lately to establish a quantitative relationship between the objective quantities characterizing road traffic noise, namely the day to night noise level, and the human subjective reaction to it as expressed by the percentage of highly annoyed people. 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 minimum comfort to the affected population.

Suggested guidelines for studying the combined effects of occupational exposure to noise and chemicals on hearing

Abstract: The present document, which describes recommended standardized procedures, aims to assist individual investigators plan a study on the effects of industrial chemicals on the auditory system, collect and analyze environmental and hearing sensitivity data that are accurate and comparable to data acquired by others. This draft document is currently being reviewed by the NoiseChem Research Group. In this peer review stage we are currently accepting critiques and suggestions to this proposal. Investigations on the aforementioned topic are necessary since there is strong evidence that occupational hearing loss may be caused not only by noise but also by exposure to certain chemicals in the work environment. Since some industrial chemicals are known to be ototoxic, it is plausible to expect that if these chemicals occurred in high enough concentrations in the workplace they could affect hearing. Laboratory studies have yielded a finding not expected, namely that when simultaneous exposure to noise and chemicals occur, the hearing loss observed was greater than the expected hearing loss from noise added to the expected hearing loss from the chemical. If this synergism is verified in humans, then changes will be required in the limits that are set for occupational hazards in order to prevent occupational hearing loss.

Chemical Asphyxiants and Noise.

Abstract: The damaging effects of noise on auditory function can be altered significantly by exposure to additional agents that may or may not by themselves be ototoxic. This chapter focuses on the ability of chemical asphyxiants present in both occupational settings and ambient environments to potentiate noise induced hearing loss in a laboratory animal model. Since the chemical agents under study do not produce permanent impairment of hearing by themselves, the finding of auditory impairment in excess of that which is produced by noise exposure alone can be defined as noise potentiation. This chapter focuses both on the exposure conditions that favour such potentiation and also on potential mechanisms for potentiation. The data show that low to moderate exposure levels of carbon monoxide (CO) and hydrogen cyanide can potentiate noise induced hearing loss (NIHL) and the relationship between such levels and those permitted in work environments is provided. Finally, evidence is presented that free oxygen radicals may be responsible for potentiation of NIHL by the chemical asphyxiants. First, the ability of a free radical spin trap agent, PBN, to prevent the adverse effects of CO is demonstrated. Then, in an additional experiment, electron paramagnetic spin resonance is used to demonstrate a high level of free radicals in the cochlea with combined exposure to CO + noise while individual exposures to CO and noise do not produce free radicals at levels detectable by this method.

The Meaning of Annoyance in Relation to the Quality of Acoustic Environments.

Abstract: A supportive environment should take care of health. It is an environment that provides complete physical, mental and social well-being. It is not suffiently characterized by infirmity or the absence of disease. It should trigger good feelings and safety (WHO, 2000). Interdisciplinary procedures are needed that include acoustics, physics, psychology, and sociology when a survey on perception of acoustic environments is carried out under the aspect of comfort. It is necessary to combine methods with different sensibilities in order to measure the subjective perception of noise in such an environment. The context, the focus of attention, and the knowledge of past experiences must be taken into account. (Ipsen, 2001) These three conditions are required to implement an adequate measurement. Subject-centred methodological procedures should be used to develop a suitable measurement procedure. Such procedures will be presented with the aim to improve social surveys that especially address the meaning of annoyance in an acoustic environment and the contribution of a soundscape.

Sleep Disturbances Related to Environmental Noise.

Abstract: The permanently open auditory channel and the ability of the brain to process incoming acoustical stimuli even while asleep and to respond adequately is the essential precondition for noise-induced sleep disturbances which are regarded as the most deleterious effects of noise. In the past, research was mainly focused on the detection and description of the various effects of noise, on the influence of personal and environmental factors, on the determination of dose ­response relations and the definition of critical noise loads, above which noise becomes intolerable. These limits are, however, as yet only tentative or applicable for a very few situations and need to be verified or revised. The present paper is focused on the priorities for future research. These are in particular 1) the causal linkage between environmental noise, primary and secondary effects on the one hand and the hypothesized contribution to multifactorial chronic diseases, to chronic annoyance, and to permanent behavioral alterations on the other hand, 2) the identification of the causes for the great discrepancies between the small effects determined in the field and the large responses recorded in the laboratory, 3) temporal aspects such as sleep at unusual times (day sleep after nightshifts), definition of night-time and day-time, 4) the significance of the shoulder hours for subsequent sleep, 5) the individual vulnerability, 6) the accumulation of data from different studies.

Stress Hormone Changes in Persons exposed to Simulated Night Noise

Abstract: The results of earlier studies attribute acute stress reactions to nocturnal aircraft noise, but do not contain detailed information on the adaptive and habituation processes during the exposure. This question was followed up with an experimental longitudinal study at Hamburg's Fiihlsbiittel airport. The test persons were exposed to nocturnal electroacoustically simulated aircraft noise in their apartments. Recorded among other things was the personal health condition, cortisol excretion collected through the night and daily collected subjective data. After the initial cortisol reaction (increasing in the first days) the course of cortisol excretion is not uniform. The results suggest that adaptation to nocturnal aircraft noise is specific to the sex. Beside these sexually specific differences there are considerable individual differences both for women and men. We found three fundamental adaptation types in agreement with results of animal experiments. From a preventive medical point of view two of the adaptation types, i.e. increasing cortisol excretion and decreasing cortisol excretion, are accompanied with health hazards. The increasing cortisol excretion exceeds the normal medical range in the process of adaptation. The decreasing cortisol level can be identified as protective inhibition. The majority of the men can be classified in the first mentioned adaptation type. From this knowledge it can be concluded that noise-induced health risk for men is to be estimated as essentially higher than for women.

Is Electronically Amplified Music too Loud? What do Young People Think?

Abstract: Listening to loud music has been associated, in a number of studies, with hearing loss and tinnitus among young people. However an unanswered question is whether or not these same young people want to have their music so loud. In our study 533 young men and 167 young women, in the age group 16 to 25, who were attending a vocational training centre, responded to a questionnaire and volunteered to have their hearing assessed. The questionnaire sought information on listening habits, on the kinds of events attended, on whether the music at these events was too loud or not, and if the respondents considered their hearing had been impaired. Analysis of this data indicated that 79% of the subjects attend discotheques, 52% pop and rock concerts, and 35% techno parties (e.g. raves). A significant number considered the music at these venues was too loud. Some 42% considered this was the case at discos, 35% thought pop and rock concerts too loud, and 39% held a similar view of techno parties. Conversely, fewer than 3% considered sound levels at these events to be too low. On the basis of the response to the questionnaire we estimate that over half the respondents (56.6%) have a sound exposure (L eq ) from music of over 87 dB(A). It is not surprising therefore that 71% reported that they had suffered tinnitus following attendance at a music event. The hearing capacity of the sample was measured by audiometry. These measurements detected hearing loss in 11% of the 700 individuals tested. However it was not possible to show that the risk of hearing loss increased with increasing exposure to loud music. We conclude that young people neither demand nor require the excessive sound levels typical of most music events.

Prevalence of arterial hypertension and myocardial infarction in relation to subjective ratings of traffic noise exposure

Abstract: A cross-sectional study was performed on a 5% sample of the adult population of the city of Pancevo (3622 residents). The response rate was 79 % (2874), with 1243 interviewed males (43%) and 1631 females (57%). Noise annoyance was assessed on a five- grade verbal scale (Not at all; Slightly; Moderately; Very; Extremely). Arterial hypertension was defined by antihypertensive treatment, information on which was obtained from questionnaire. Myocardial infarction was also subjectively confirmed. Prevalence and odds ratios of arterial hypertension and myocardial infarction were computed for subjects who were very much and extremely annoyed by noise, or moderately annoyed, using residents who were slightly annoyed or not annoyed at all as a referent category. Significant odds ratios (adjusted for age, body mass index and smoking habits) were found for self-reported arterial hypertension [1,8 (1,0-2,4 - 95% confidence interval) , P < 0,01] and myocardial infarction [1,7 (1,0 - 2,9), P < 0,05] in very much or extremely noise disturbed male subjects, compared to those who were not annoyed at all, or were slightly annoyed by noise. The respective odds ratios for females were lower and not statistically significant 1,1 (0,8-1,7) and 1 (0,4 - 2,0).

Occupational exposure to insecticides and their effects on the auditory system.

Abstract: The objective of this investigation was to study the effects of occupational exposure to organophosphates and pyrethroid insecticides on the central auditory system. The study group consisted of 98 workers exposed to insecticides and 54 non-exposed workers. Data on work history, medical history, present diseases, occupational and non-occupational exposure to noise or chemicals and lifestyle factors were obtained through an interview. Central auditory system functions were assessed through frequency patterns and duration patterns testing. Fifty-six percent of the exposed workers had hearing dysfunction at the central level and its relative risk was 7.58 for the group with exposure to insecticides (95% CI 2.9- 19.8) when compared to the non-exposed group. The group exposed to insecticides and noise had a relative risk for central disorders of 6.5 (95% CI 2.2-20.0) when compared to the non-exposed group and 9.8 (95% CI 1.4-64.5) when compared to the group exposed only to noise. The finding suggests that exposure to organophosphates and pyrethroid products can induce damage to central auditory system. Further research is needed on the ototoxic mechanisms of these chemicals, and on hearing loss prevention measurements that are applicable and adequate to such risks and populations.

A cross-sectional study of occupational noise exposure and blood pressure in steelworkers

Abstract: Objective: To determine the association of occupational noise exposure and blood pressure in a group of workers at the metallurgical plant. Methods: Noise exposure at the workplace and blood pressure were measured in 178 male workers of steel mill company. Criteria for including in the study group were: age below 35 years, employment-exposure duration longer than 3 years, hearing threshold level in normal range and no cardiovascular history. Program of examination included: individual questionnaire, ORL - examination, tone audiometry, measure of weight, height and blood pressure. Cigarette smoking, diet habits and other risk factors of elevated blood pressure were controlled. Noise exposure was assessed for each work place, by means of direct and indirect measurements. Results: Systolic blood pressure was statistically significantly higher in the group exposed to the higher noise levels and the results of multiple regression analyses revealed a significant relationship between the occupational exposure to noise and systolic blood pressure. No such relationship with diastolic blood pressure was found. Conclusions: The results suggest the positive association between occupational exposure to noise and blood pressure.

NoiseChem: An European Commission research project on the effects of exposure to noise and industrial chemicals on hearing and balance.

Abstract: Exposure to multiple physical and chemical agents is common in occupational environments but workplace hazards and occupational safety criteria for combined exposures is lacking. NoiseChem is an European Commission research project examining the effects of exposure to noise and chemicals on hearing and balance. Partners in Sweden, Finland, France, Denmark, UK and Poland with expert guidance from partners in USA will examine workers and study the mechanisms of action in animals to determine the levels of risk associated with joint expo­sure to noise and solvents. This paper briefly outlines the project details.

Estimated leisure-time noise exposure and hearing symptoms in a finnish urban adult population.

Abstract: The aim of this study was to determine a statistical measure for total weekly noise exposure from leisure-time noise activities in a Finnish urban adult population. The subjects´ time consumed in noisy activities, and their self-evaluated loudness of the activities converted into equivalent noise levels of the activities were used in the calculation of weekly noise exposure levels. Self-reported hearing symptoms (i.e., tinnitus, pain in the ear) and hearing loss due to noise exposure were also asked with the questionnaire. No measurements of sound level or hearing loss were made in this study. Forty-one per cent of subjects were estimated to be exposed to noise at levels over 75 dBA, and 9% of the subjects had weekly exposure that was over 85 dBA. The incidence of hearing symptoms seemed to correlate with increased noise dose and age. The noisiest leisure-time activities were going to night-clubs and pubs, using home tools, playing in a band or orchestra, shooting and attending or participating in motor sports.

The effect on earmuff attenuation of other safety gear worn in combination

Abstract: This study assessed the effect of other safety gear worn in proximity on the attenuation afforded by earmuffs attached to a hard hat. Seventy-two males and females participated: 24 under the age of 40 years with normal hearing, and 48 over the age of 40 years, half with normal hearing and half with bilateral high-tone hearing loss. Measurements were made with the ears unoccluded, with the muffs on hard hat alone, and with the muffs on hard hat in combination with safety glasses, an air-purifying half mask respirator or both glasses and respirator. They included (1) diffuse field hearing thresholds from 0.25-8 kHz, and (2) consonant discrimination in quiet and in 80-dB SPL speech spectrum noise. Attenuation was derived by subtracting the unoccluded from the protected hearing threshold at each frequency. Muff attenuation was within 6 dB of the manufacturer's specifications but decreased by as much as 5 dB when the glasses or respirator were worn and by 9 dB with both these devices. Males achieved 3 dB higher attenuation than females. However, hearing status had no effect. Consonant discrimination was significantly worse in noise. The impaired subjects performed more poorly when wearing the muff on hard hat but there was no additional effect of wearing the glasses and/or respirator. These results demonstrate that wearing other protective safety gear around the head can interfere with the hearing protection provided by earmuffs. They also confirm that for people with a hearing loss, the use of earmuffs may increase the communication handicap.

The Need for a Specific Noise Measurement for Population Exposed to Aircraft Noise during Night-time.

Abstract: Most of subjective complaints about aircraft noise during night-time refers to sleep disruption. In order to protect populations who live around airports, it is of major importance to define levels of noise considered to be unacceptable during that particular time of the 24-hour period. In addition to an integrated indicator which describes the global noise exposure (Lden), the French authority on airport noise control (Autorite de Controle des Nuisances Sonores Aeroportuaires: ACNUSA) is considering the possibility of defining a maximum noise level [LAmax (1s)] that should not be exceeded at night (from 22.00 to 06.00) by any flying aircraft over residential areas. The main benefit of this single event indicator would be the identification of contravening vessels and application of possible penalty. It is believed that this type of sanction would help protecting sleep in highly noise-exposed areas.

Ototoxic effects of styrene alone or in concert with other agents: A review.

Abstract: Styrene is an organic solvent employed in many manufacturing industries, as well as in other economic sectors. Recently, evidence is beginning to accumulate on the hazardous effects that styrene exposures have on the auditory system. In rats, a well-suited metabolic animal model for these studies, aromatic solvents seem to affect the auditory sensitivity mainly in the cochlear mid-frequency range. Outer hair cells are the primary targets within the organ of Corti, although the spiral ganglions are not spared. Therefore, styrene must be considered as an ototoxic chemical agent that can be potentially neurotoxic. Finally, noise-styrene exposures can have synergistic effects on the auditory system. The findings reported in both human and animal studies indicate that exposures to styrene, or to styrene associated to noise, may dramatically impact occupational hearing conservation practices and legislation. Human and animal studies will be summarized in discussing the effects of styrene alone or in combination with noise and other chemicals. Gaps in scientific knowledge are highlighted to assist future research.

Night-time Noise Annoyance: State of the Art.

Abstract: The annoyance-reaction is one of the central variables in noise research After an introduction to different concepts and definitions of noise annoyance different scales of how noise annoyance can be measured are shown The question is discussed whether disturbance effects of noise at different times of day are given To clarify this problem, the results of a series of actual German noise studies are reported In these studies differences between day- and night­time annoyance are found depending on the sound sources For the case of road traffic noise no differences between day and night-time annoyance were found In contrast, annoyance reactions are related to the time of day for railway and air traffic noise Especially for aircraft noise, above a Leq of 50 dB(A) night-time annoyance rises faster than day-time annoyance The effects are discussed in the frame of a cognitive model of noise annoyance It is argued that annoyance judgments are based on an internal representation of the noise situation Part of this representation are the event characteristics of the sound sources and their estimated impacts for disturbances at different times of day

Urban noise in the City of Sao Paulo, Brazil : An important problem of public health

Abstract: OBJECTIVES: To estimate the sound pressure levels in areas with heavy and with local traffic in the city of Sao Paulo and compare the data obtained with the thresholds established by the local law. METHODS: Twenty-eight points in roads with heavy and local traffic were chosen. The measurements were done Monday to Friday, 8 am to 5 pm, using a 2236 Mediator (Bruel & Kjaer) following the International Standard (ref. no. 1996/1982 1,2,3). Each point was measured a number of times to produce a standard error lower than 1 dB. RESULTS: The equivalent continuous A-weighted sound pressure level (Leq) for the roads with heavy traffic ranged from 70.88 to 80.18 dB(A), mean 75.88 dB(A) (95% CI: 74.49; 77.27) and the maximum peak (MaxP) ranged from 102.47 to 108.37 dB(C), mean 105.63 dB(C) (95% CI: 104.59; 106.68). For the roads with local traffic we observed: Leq from 50.82 to 66.88 dB(A), mean 61.11 dB(A) (95% CI: 57.97; 64.26) and MaxP 83.13 to 97.33 dB(C), mean 92.81 dB(C) (95% CI: 89.80; 95.82). There was a strong evidence, p < 0,001, in favour of the difference between the two types of traffic roads regarding the sound pressure levels. CONCLUSIONS: The Brazilian Standards establishes 50dB(A) and 70dB(A) as the maximum limits for environmental noise in residential and industrial areas, respectively. The results of this study indicate that the problem of urban noise in the city of Sao Paulo needs to be tackled urgently due to its important public health impact.

Complaints and Annoyance caused by Aircraft Operations: Temporal Patterns and Individual Bias.

Abstract: The impact of aircraft movements on annoyance in the local community surrounding a major international airport was assessed for (a) patterns of complaints for the year, month, day-of­ the-week and time-of-day and (b) the frequency of complaining by individuals. Complaint data from Manchester Airport since 1991 and detailed analysis for 1998 were compared with associated information on noise monitoring and aircraft movements to investigate underlying biological and sociological patterns. The annual number of complaints peaked in 1996 when the 'Manchester Airport Second Runway Public Inquiry' was a major local issue and had a high profile in the local media. Since 1996 the number of flights has increased while the number of complaints has steadily fallen; from 50 to13 complaints per 1,000 movements from 1996 to 1999. Detailed inspection of the 1998 data revealed a total of 2072 noise complaints from 594 individuals but, while the majority of individuals complained once or twice, three individuals accounted for 41% of complaints. This introduced some bias into the results but there was; (a) a steady increase in complaints (per 1,000 movements) over the week from a low on Monday to a high on Saturday/Sunday; (b) a marked hourly variation over the 24 hours in both flight frequency (movements per hour) and complaints. However, the hourly patterns in flight frequency and complaints were clearly distinct. Calculations of the complaints per aircraft movement (a reflection of sensitivity) for each hour of the day showed a striking 24h pattern with twice as many complaints between 23.00 and 07.00 as the rest of the day (07.00­23.00). Late evening and night-time, particularly during the early hours of sleep, was the time of greatest sensitivity to aircraft, with or without the serial complainers. These results could be used to inform airport operations to minimize community disturbance.

The Joint Effect of Industrial Noise Exposure and Job Complexity on All-Cause Mortality - The CORDIS Study.

Abstract: In a previous follow-up study of industrial workers (the CORDIS study, Melamed et al., 1999a) we demonstrated a dose-response relationship between occupational noise exposure levels and all-cause mortality. In that study the type of jobs that workers were engaged in was not taken into account. However, in further analyses of CORDIS data we have found that noise exposure is particularly detrimental to health for workers engaged in complex jobs. Therefore in this 12-year study we attempted to determine the combined effect of job complexity and noise exposure on all-cause mortality in 2606 industrial workers. We divided the workers into four groups based on a combination of either high or low noise exposure, and whether they performed simple or complex jobs. There was an increased risk for all-cause mortality (OR = 1.86, 95% CI = 1.04-3.32), in workers who performed complex jobs under high noise exposure levels compared to those who performed simple jobs under low noise exposure. This remained significant even after adjusting for possible confounding variables. There was a trend for a more pronounced effect among less educated workers, among blue-collar workers, and in those with higher tenure. We conclude that occupational noise exposure is associated with excess mortality risk among workers performing complex jobs.

Solvents impair balance in Man.

Abstract: Solvents are commonly used in many industries and therefore exposure to multiple solvents is a common occupational hazard. A myriad of peripheral and central nervous system toxic effects can be produced by both acute and chronic low level exposures. Dizziness is often an early symptom of solvent exposure but has only in recent times been investigated specifically. The indications from the studies reviewed are that vestibular disturbances are common in workers exposed to solvents and dose-response relationships need to be established for early detection of vestibulo-toxicity.

Cortical Excitations, Cortisol Excretion and Estimation of Tolerable Nightly Over-Flights.

Abstract: Noise induces cortisol excretion even below the awakening threshold. This is based upon the existence of very close subcortical central nervous connections between parts of the auditory system (e. g. amygdala) showing typical plasticity effects and the hypothalmic-pituitary-adrenal (HPA)-axis. Repeated noise events (e.g. over-flights during nigh-time) will lead to accumulation of the cortisol concentration in blood. This happens because its time constant of exponential decrease is about 50 to 10 times larger than that one for adrenaline and noradrenaline. A twofold attempt has been made to calculate the cortisol accumulation using an initial value of noise induced small cortisol increase (rounded value 14 ng/ml) at the nightly threshold of beginning vegetative overreaction around 53 dB(A). A mean time-constant of 64 min has been applied based upon experimental studies. Using in a first step the range of minimal and maximal normal cortisol values as border line and taking into account a relation between peak sound pressure level and cortical excitation given by a power function (exponent 0.32, based on evoked potential studies in man) results in a formula to estimate tolerable events during night-time periods (over-flights in a given time range). Examples of results for 8 hours in the night are for instance values of 11 events with 55 dB(A) indoor peak level or 5 events with 75 dB(A) indoor peak level respectively. Those values of tolerable nightly noise events estimated on the basis of physiological processes and peak levels cannot be recalculated as or compared with equivalent sound levels.

Aircraft noise exposure from schiphol airport: a relation with complainants.

Abstract: The possible relation between aircraft noise exposure and the prevalence of complainants around Schiphol airport was studied. The home address of people who complain about aircraft noise at the Environment Advisory Committee Schiphol was combined with annual average noise levels, using a Geographic Information System. The prevalence of complainants in areas with different noise exposure was calculated. In addition, data from a questionnaire survey was used to gain insight into the influence of sound insulation, personal characteristics, and aspects of health on complaint behaviour. The prevalence of complainants increases from < 1% at 50 dB(A) (Lden) to about 7% at 62 dB(A). Above this level the prevalence drops back to < 3%. An increase in the percentage of sound insulated houses with increasing noise levels is observed, rising markedly above 60 dB(A) (from 24% to almost 90%). When comparing people who complain with those who do not complain about aircraft noise, complainants report more noise annoyance (OR=10.2, 95% CI=8.54-12.3), sleep disturbance (OR=9.87, 95% CI=8.19-11.9), concern about health (OR=8.02, 95% CI=6.75-9.53), and fear for an aircraft crash (OR=3.64, 95% CI=3.07-4.31). Results indicate a relation between aircraft noise exposure and the prevalence of complainants, possibly influenced by sound insulation. Important determinants of complaint behaviour apart from noise level are noise annoyance, sleep disturbance, concern about health, and fear for an aircraft crash. Although complainants do not seem to be representative for the total population, and do not reflect the full extent of noise annoyance, their prevalence does reflect the regional distribution of aircraft noise annoyance in a noise polluted area.

Environmental Noise and Community in Hong Kong.

Abstract: In order to find out the attitude of the community towards environmental noise, community surveys were conducted over the territory of Hong Kong through telephone sampling. Specific surveys were also carried out for areas previously affected by severe aircraft noise. Main observations on the community's response towards noise are that noise pollution was ranked the third among five selected social concerns (after "air pollution" and "security", and higher than "traffic jam" and "cleanliness"); about 60% of the respondents found the territory "noisy"; the most annoying noise source was "traffic noise"; 40% of people found the most annoying noise not tolerable and that most people affected by noise suffered from "distraction". Nonetheless, many did nothing (e.g. did not complain) against the noise and still preferred an open-window life style.

Noise Annoyance Modelling using Fuzzy Rule Based Systems.

Abstract: This paper presents a model that uses a fuzzy rule based engine to predict noise annoyance reported by individuals in a social survey. The rules are proposed by the human expert and are based on linguistic variables. The approach then adapts the sufficiency degree or certainty of a rule to tune the model to a particular survey. Although all possible relations between exposure, attitudinal, emotional, personal, environmental and social variables are not included in the model as yet, the benefits of the new approach are clearly demonstrated. A major limitation that remains is the varying theoretical and empirical basis of the expert for different subset of annoyance determinants. Future applications may include more accurate predictions of noise annoyance for policy support and extraction of knowledge concerning the construct of annoyance from surveys.

Effects of Occupational Exposure to Mercury or Chlorinated Hydrocarbons on the Auditory Pathway.

Abstract: The purpose of this study was to examine the effects of industrial exposure to mercury and chlorinated hydrocarbons (CH) on the auditory pathway. To this effect, auditory brainstem responses (ABR) were recorded from 40 workers exposed to mercury, 37 workers exposed to CH and from a control group of 36 subjects that were never exposed to neurotoxic substances. The interpeak latency (IPL) of waves I-III, III-V and I-V were measured. The mean duration of exposure to mercury and CH was 15.5 (+6.4) and 15.8 (+7.2) years respectively. The air sample monitoring of mercury was 0.008 mg/m3 (0.32 of the Threshold Limit Value - TLV® as published by ACGIH 2000). The mean average air sample monitoring was found to be 98 ppm for TCE, 12.7 ppm for PCE and 14.4 ppm for TCA which is respectively between 0.28 - 0.51 of the TLV® of CH. The mean blood mercury (B-Hg) levels were found to be 0.5mgr% (+0.3mgr%), which is 0.13 of the upper range of the permitted biologic exposure index (BEI) published by the ACGIH 2000. The mean urine samples levels of trichloroacetic acid were between 0.11-0.2 of the permitted BEI for the CH workers. The percent of workers exposed to mercury and CH workers with abnormal prolongation of IPL I-III was higher than the control group (42.5% and 33.8% vs. 18.0% respectively p<0.02). These results are consistent with other studies and show that ABR may provide a sensitive tool for detecting subclinical central neurotoxicity caused by CH and mercury

Sleep Studies Before and After - Results and Comparison of Different Methods.

Abstract: The effects of long-term exposure to road traffic noise on sleep quality were assessed using questionnaires and acetimetry. Results obtained before and after reduction in road traffic were compared. Sleep quality was improved after the reduction of noise levels. There was some correlation between acetimetry parameters and subjective parameters.

Noise Mapping and Annoyance.

Abstract: The EC has published a Green Paper on noise policy in the EU and has issued a directive on the assessment and reduction of environmental noise. This directive will make noise mapping mandatory for cities with at least 250.000 inhabitants. Due to the development in computer technology it is possible to calculate noise maps for large urban areas using the available data on buildings, ground profile, road and rail traffic. Examples for noise mapping are Birmingham (GB), Linz (A) and various German cities. Based on noise maps and empirical data on the correlation between annoyance and noise levels annoyance maps for different sources (rail, road, aircraft) can be calculated. Under the assumption that the annoyance for the different sources are only weakly correlated, a combined annoyance map can be calculated. In a second step using the distribution of the population the actual number of annoyed people can be evaluated. This analysis can be used, for example, to identify noise hot spots and to assess the impact of major traffic projects - roads, airports- on the noise situation as well as the impact on the population. Furthermore, the combined annoyance maps can be used to investigate on health effects and to check whether or not empirical correlations between annoyance and noise levels are sufficiently correct.

The challenge of solvent substitution in coatings

Abstract: A brief outline of the role of solvents in surface coatings is given, to provide the background to the problems encountered in solvent substitution. The direct substitution of one solvent by another is relatively straightforward. Computer programs greatly simplify the process. However, the real challenge lies with the reduction in solvent use, through the development of low solvent coatings. While this is a process that has been going on for many years, there is no doubt that recent regulatory pressures regarding both occupational health and environmental standards have made it the single most important challenge for the industry. Examples are discussed of the development of high solids, low solvent industrial coatings as well as water borne industrial coatings. Although there has been rapid progress in recent years, there is no prospect in sight for the complete elimination of solvents. Good workplace hygiene must therefore remain a key element in the safe use of coatings.