Environmental and personal monitoring of exposure to urban noise and community response

Noise exposure of a population sample living in a city in northern Italy (Genoa) was assessed by measuring the noise in the area as well as with personal sound detectors. Sampling was conducted during a standard day and covered a period of time spent out-of-doors, at work (service sector) and at home. Ambient noise at home and at work was assessed with sound-level meters, personal exposure levels were assessed with personal sound-level/dosimeters. Information regarding each environment was obtained with an interview including also a subjective judgement on traffic intensity and noise levels. The mean individual equivalent continuous sound level (L_eq) of recorded noise was 74.5 dB(A) for 24 h and 63.9 dB(A) at night. A further distinction was made between noise exposure at home (L_eq 74.4), work (L_eq 74.0) and during city transfers (L_eq 79.3). L_eq values for individual hours, Leq daytime (L_{eq, d}), Leq nighttime (L_{eq, n}) and Leq day-night (L_dn) indices calculated in the different environments, i.e. at work, home and out-of-doors, are reported here. Individual noise levels have then been compared with environmental data and with subjective noise exposure judgement.     

Industrie- und Gewerbel?rm

Zusammenfassung In der Umgebung von fünf Industrie- und Gewerbeanlagen wurden die Lärmimmissionen gemessen und mittels schriftlicher Befragung die Auswirkungen derselben auf die dort wohnenden Menschen erfasst.Es zeigte sich, dass gehäufte Störungen und Reaktionen bei Betriebslärmimmissionen tagsüber ab einemL _eq von ungefähr 50 dB(A) auftreten und nachts ab einemL _eq von ungefähr 40 dB(A).

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Noise immissions of industrial plants

Summary In the surroundings of five industrial plants noise immissions were measured, and people were asked by questionnaire about the effects caused by noise.The results show that increased disturbances and reactions to industrial noise immissions occur at daytime with anL _eq of about 50 dB(A) and at nighttime with anL _eq of about 40 dB(A).

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Immissions de bruit des entreprises industrielles

Résumé Dans les environs de cinq entreprises industrielles, on a mesuré les immissions de bruit, et les habitants ont été questionnés sur les effets causés par le bruit.Les résultats montrent que les troubles et réactions augmentent à partir d'une valeurL _eq située environ à 50 dB(A) pour le jour et à 40 dB(A) environ pour la nuit.

     

Diurnal variability of transportation noise exposure and cardiovascular mortality: A nationwide cohort study from Switzerland

Background

Most epidemiological noise studies consider 24?h average noise exposure levels. Our aim was to exploratively analyze the impact of noise exposure at different time windows during day and night on cardiovascular mortality.

Spatial Variation in Environmental Noise and Air Pollution in New York City

Exposure to environmental noise from traffic is common in urban areas and has been linked to increased risks of adverse health effects including cardiovascular disease. Because traffic sources also produce air pollutants that increase the risk of cardiovascular morbidity, associations between traffic exposures and health outcomes may involve confounding and/or synergisms between air pollution and noise. While prior studies have characterized intraurban spatial variation in air pollution in New York City (NYC), limited data exists on the levels and spatial variation in noise levels. We measured 1-week equivalent continuous sound pressure levels (L_eq) at 56 sites during the fall of 2012 across NYC locations with varying traffic intensity and building density that are routinely monitored for combustion-related air pollutants. We evaluated correlations among several noise metrics used to characterize noise exposures, including L_eq during different time periods (night, day, weekday, weekend), L_dn (day-night noise), and measures of intermittent noise defined as the ratio of peak levels to median and background levels. We also examined correlations between sound pressure levels and co-located simultaneous measures of nitric oxide (NO), nitrogen dioxide (NO₂), fine particulate matter (PM_2.5), and black carbon (BC) as well as estimates of traffic and building density around the monitoring sites. Noise levels varied widely across the 56 monitoring sites; 1-week L_eq varied by 21.6 dBA (range 59.1–80.7 dBA) with the highest levels observed during the weekday, daytime hours. Indices of average noise were well correlated with each other (r > 0.83), while indices of intermittent noise were not well correlated with average noise levels (r < 0.41). One-week L_eq correlated well with NO, NO₂, and EC levels (r = 0.61 to 0.68) and less so with PM_2.5 levels (r = 0.45). We observed associations between 1-week noise levels and traffic intensity within 100 m of the monitoring sites (r = 0.58). The high levels of noise observed in NYC often exceed recommended guidelines for outdoor and personal exposures, suggesting unhealthy levels in many locations. Associations between noise, traffic, and combustion air pollutants suggest the possibility for confounding and/or synergism in intraurban epidemiological studies of traffic-related health effects. The different spatial pattern of intermittent noise compared to average noise level may suggest different sources.     

H?rsch?den in der Industrie

Zusammenfassung Untersuchungen der vorübergehenden Verschiebung der Hörschwelle werden als Modellsituation für die Erforschung der dauernden Hörverluste angewendet. Die vorübergehende Verschiebung der Hörschwelle durch Schallreize von hohen Intensitäten von mehr als 90 dB ist um ein Mehrfaches grösser als diejenige durch niedrige Intensitäten. Sie ist proportional der Expositionsdauer. Ihr Abklingen dauert 10mal länger als die Dauer des verursachenden Schallreizes. Die vorübergehende Verschiebung der Hörschwelle wird durch alternierende Lärm- und Ruheperioden um die Hälfte geringer als durch einen kontinuierlichen Lärm der gleichen akustischen Energie. — Ein gleichbleibender Lärm soll den Grenzwert von 90 dB(A) nicht erreichen. Eine nicht-kontinuierliche Lärmsituation ist mittels des äquivalenten Dauerschallpegels L_eq zu bewerten, sie soll den L_eq-Wert von 90 dB(A) nicht erreichen. Das Risiko der Gehörbeeinträchtigung durch einen übermässigen Lärm kann mittels des L_eq und der Expositionsdauer in Jahren eingeschätzt werden. Erreicht oder überschreitet eine Lärmsituation den Grenzwert, sind Schutzmassnahmen zu treffen. Durch technische Massnahmen kann der Lärm an der Quelle und bei der Ausbreitung reduziert werden. Durch organisatorische Massnahmen kann die Expositionsdauer gekürzt werden. Die Hörschutzgeräte bieten die letzte Verhütungsmöglichkeit, doch sie sollen keinesfalls die andern Schutzmassnahmen ersetzen.

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Hearing damage in industry

Summary Test on temporary displacement of the hearing threshold are used as model situations for studies on permanent loss of hearing. Temporary displacement of the hearing threshold by means of sounds of high intensity of more than 90 dB is several times as big than that caused by low intensities. This displacement is proportional to the duration of the exposure. Its decrease lasts ten times as long as the sound having provoked the displacement.The temporary displacement of the hearing threshold following alternating periods of noise and quiet represents only half of the displacement caused by a continuous noise of the same acoustical energy.A continuous noise may not reach the threshold of 90 dB(A). An interrupted noise has to be evaluated by means of the equivalent noise level L_eq and may not reach the value L_eq of 90 dB(A). The risk of deafness caused by excessive noise can be evaluated by means of L_eq and the duration of exposure in years. If a situation reaches or surpasses the limit, protection measures have to be taken. With the help of technical measures, noise can be reduced at the source as well as in its spreading. Organisational measures can shorten the duration of exposure. Finally, individual hearing protection apparatuses offer a preventive measure, but in no case can they replace the other means of protection.

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La surdité dans l'industrie

Résumé Des essais sur le déplacement temporaire du seuil auditif servent de modèle pour l'étude de la surdité permanente. Le déplacement temporaire du seuil auditif causé par des sons de haute intensité (plus de 90 dB) est de plusieurs fois plus marqué que celui causé par des intensités faibles. Ce déplacement est proportionnel à la durée de l'exposition. Son décroissement dure dix fois de plus que le son qui a provoqué le déplacement.Le déplacement temporaire du seuil auditif à la suite de périodes alternées de bruit et de calme ne comporte que la moitié du déplacement causé par un bruit continu de même énergie acoustique.Un bruit continu ne doit pas atteindre le seuil de 90 dB(A). Un bruit discontinu est à évaluer au moyen du niveau sonore équivalent permanent L_eq et ne doit pas atteindre la valeur L_eq de 90 dB(A). Le risque de surdité par un bruit excessif peut être évalué au moyen du L_eq et de la durée de l'exposition en années. Lorsque une situation de bruit atteint le seuil limite, il faut appliquer des mesures de protection. Le bruit peut être atténué à la source et lors de sa propagation avec des moyens techniques. Des mesures organisatrices sont capables de réduire la durée de l'exposition. Enfin, les appareils individuels protègent également contre le bruit, mais ils ne doivent en aucun cas remplacer les autres mesures de protection.

     

Individual Daytime Noise Exposure during Routine Activities and Heart Rate Variability in Adults: A Repeated Measures Study

Background: Epidemiological studies have demonstrated associations between noise exposure and cardiovascular events. However, there have been few studies of possible underlying mechanisms.Objectives: We examined the association between individual daytime noise exposure and heart rate variability (HRV).Methods: In a prospective panel study in Augsburg, Germany (March 2007–December 2008), 110 individuals participated in 326 electrocardiogram recordings with a mean duration of 6 hr. Five-minute averages of heart rate (HR) and HRV parameters were determined. Individual noise exposure was measured as A-weighted equivalent continuous sound pressure levels (L_eq). Effects were estimated using additive mixed models adjusted for long- and short-term time trends and physical activity. Due to nonlinear exposure–response functions, we performed piecewise linear analyses with a cut-off point at 65 dB(A).Results: Concurrent increases of 5dB(A) in L_eq < 65dB(A) were associated with increases in HR (percent change of mean value: 1.48%; 95% CI: 1.37, 1.60%) and the ratio of low-frequency (LF) to high-frequency (HF) power (4.89%; 95% CI: 3.48, 6.32%), and with decreases in LF (–3.77%; 95% CI: –5.49, –2.02%) and HF (–8.56%; 95% CI: –10.31, –6.78%) power. Standard deviation of normal-to-normal intervals (SDNN) was positively associated with concurrent noise < 65dB(A) (5.74%; 95% CI: 5.13, 6.36) but negatively associated with noise lagged by 5–15 min (–0.53% to –0.69%). Associations with cardiac function were less pronounced for noise ≥ 65dB(A), with some in opposite directions from associations with noise < 65dB(A). Concurrent associations were modified by sex and age.Conclusions: Individual daytime noise exposure was associated with immediate changes in HRV, suggesting a possible mechanism linking noise to cardiovascular risk. Noise at lower levels may have health consequences beyond those resulting from “fight-or-flight” responses to high levels of noise.     

Le bruit du trafic routier

Résumé Le niveau sonore équivalant à un niveau constant L_eq ou la somme des fréquences des niveaux sonores L₅₀ sont les procédés de mesure du bruit du trafic routier les mieux appropriés à l'évaluation de la gêne. La propagation du bruit au voisinage d'une route dépend de l'intensité du trafic ainsi que de la distance de la route. Les niveaux sonores moyens baissent de 3 dB dans la zone éloignée lorsque la distance est doublée. D'autre part, un dédoublement du trafic cause une élévation du niveau sonore de 3 dB.Les effets principaux du bruit du trafic sont les perturbations du sommeil et le trouble de la compréhension de conversations. Des limites tolérables pour des régions habitées et non habitées sont proposées.

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Traffic noise

Summary The equivalent noise level L_eq and the cumulative noise level L₅₀ are the most indicated measures for judging annoyances caused by traffic noise. The propagation of traffic noise in the neighbourhood of roads depends on the traffic density and distance from the road. The mean level decreases by 3 dB when the distance is doubled. On the other hand doubling of traffic density causes an increase of the noise level by 3 dB.The main effects of traffic noise are disturbances of sleep and prejudice to speech communication. Tolerable limits for urbanized and not yet urbanized areas are proposed.

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Strassenlärm

Zusammenfassung Der äquivalente Dauerschallpegel L_eq und der Summenhäufigkeitspegel L₅₀ sind die bestgeeigneten Masse zur Beurteilung der Belästigung durch Strassenverkehrslärm. Die Ausbreitung des Verkehrslärms in der Umgebung von Strassen hängt von der Verkehrsdichte und von der Entfernung ab. Im Fernfeld nimmt der mittlere Lärmpegel bei Verdoppelung der Distanz um 3 dB ab. Anderseits bewirkt eine Verdoppelung der Verkehrsdichte eine Erhöhung des Lärmpegels um 3 dB.Unter den Wirkungen des Verkehrslärms kommt den Störungen des Schlafs und der Beeinträchtigung der Sprachverständlichkeit die grösste Bedeutung zu. Es werden Grenzwere für bebaute und nicht bebaute Gebiete vorgeschlagen.

     

The spatial relationship between traffic-generated air pollution and noise in 2 US cities

Traffic-generated air pollution and noise have both been linked to cardiovascular morbidity. Since traffic is a shared source, there is potential for correlated exposures that may lead to confounding in epidemiologic studies. As part of the Multi-Ethnic Study of Atherosclerosis and Air Pollution (MESA Air), 2-week NO and NO₂ concentrations were measured at up to 105 locations, selected primarily to characterize gradients near major roads, in each of 9 US communities. We measured 5-min A-weighted equivalent continuous sound pressure levels (L_eq) and ultrafine particle (UFP) counts at a subset of these NO/NO₂ monitoring locations in Chicago, IL (N=69 in December 2006; N=36 in April 2007) and Riverside County, CA (N=46 in April 2007). L_eq and UFP were measured during non-“rush hour” periods (10:00–16:00) to maximize comparability between measurements. We evaluated roadway proximity exposure surrogates in relation to the measured levels, estimated noise–air pollution correlation coefficients, and evaluated the impact of regional-scale pollution gradients, wind direction, and roadway proximity on the correlations. Five-minute L_eq measurements in December 2006 and April 2007 were highly correlated (r=0.84), and measurements made at different times of day were similar (coefficients of variation: 0.5–13%), indicating that 5-min measurements are representative of long-term L_eq. Binary and continuous roadway proximity metrics characterized L_eq as well or better than NO or NO₂. We found strong regional-scale gradients in NO and NO₂, particularly in Chicago, but only weak regional-scale gradients in L_eq and UFP. L_eq was most consistently correlated with NO, but the correlations were moderate (0.20–0.60). After removing the influence of regional-scale gradients the correlations generally increased (L_eq–NO: r=0.49–0.62), and correlations downwind of major roads (L_eq–NO: r=0.53–0.74) were consistently higher than those upwind (0.35–0.65). There was not a consistent effect of roadway proximity on the correlations. In conclusion, roadway proximity variables are not unique exposure surrogates in studies of endpoints hypothesized to be related to both air pollution and noise. Moderate correlations between traffic-generated air pollution and noise suggest the possibility of confounding, which might be minimized by considering regional pollution gradients and/or prevailing wind direction(s) in epidemiologic studies.     

Effects of noise on mental performance with regard to subjective noise sensitivity

Summary Objective and subjective effects of moderate levels of recorded traffic noise [L_eq = 55 dB(A) and 75 dB(A)] on mental performance were studied in a laboratory setting. A total of 45 subjects (23 males and 22 females) were investigated with respect to subjective noise sensitivity (SNS). Four cognitive tasks were applied involving different psychological functions: Short-Term Memory (STM), Search and Memory 5 (SAM 5) (vigilance), Hidden Figures (HF) (spatial reasoning) and Mental Arithmetic (MA) (parallel processing). Three groups of 15 subjects were defined according to their scores on Weinstein's Noise Sensitivity Scale as tolerant, moderately sensitive or highly sensitive to noise. A similar level of performance was observed in the three groups under quiet conditions [30 dB(A) L_eq], but under noisy conditions significant differences (P<0.05) were seen between them on the STM (words) and MA (total results) tasks, and the lowest performance accuracy was demonstrated by the noise-sensitive subjects. SNS was the primary factor responsible for these differences. There were no significant differences between the groups in respect of the SAM 5 and HF tasks, under either quiet or noisy conditions. Annoyance while performing tasks under noisy conditions was regularly and significantly higher among subjects judged to be noise sensitive on Weinstein's scale, as compared with those judged to have low or moderate SNS.     

Pilot study of patron sound level exposure in loud restaurants,bars, and clubs in New York city

Visiting restaurants, bars, clubs, and lounges is a regular part of urban cultural life for residents and tourists alike; however, anecdotal reports and diner surveys suggest that sound levels are excessive and diners dislike them. High sound levels in these venues can contribute to both patron and employee overexposure, and young people may be particularly at risk. To supplement the paucity of literature and data on noise in urban venues, patron noise exposure was measured inside a sample of loud New York City restaurants, bars, clubs, and lounges. Sound level measurements were obtained in 59 venues. Field staff conducted one 20–162 minute visit per venue on a Thursday, Friday, or Saturday evening. The equivalent continuous sound pressure level on the A-scale (L_Aeq) was calculated for each visit. Median and mean L_Aeq among all venues sampled were both 92 decibels (dBA). Clubs and lounges had a higher mean L_Aeq than restaurants and bars (97 vs. 91 dBA, p < 0.05). A greater number of patrons was associated with a higher L_Aeq. Higher L_Aeq values were observed during later hours of the evening (9 PM and later). For 80% (N = 47) of the venues, the L_Aeq was above 85 dBA. In 49% (N = 29) of the venues, the visit exceeded the maximum allowable daily noise dose based on National Institute of Occupational Safety and Health (NIOSH) Recommended Exposure Limit (REL) of 85 dBA 8-hr Time-Weighted Average (TWA). Venues should assess indoor sound levels including employee exposure and aim to maintain sound levels that are within NIOSH guidelines.     

High-frequency audiometry in the evaluation of critical noise intensity

Summary We investigated a total of 537 subjects (68 men, 469 women) working in the textile industry to ascertain their hearing level in the conventional hearing range as well as in the high-frequency (HF) range. The persons we tested work at three different noise-levels [80–84, 85–89, 90–94dB (A), measured as l_eq). The differences in the hearing thresholds between this three groups mentioned were checked by means of discriminant analysis. The first hearing level changes at a noise-level below 90 dB (A) l_eq develop mainly in the HF range. In the conventional hearing range, however, the hearing levels remain unchanged even over long exposure times. Noise-induced hearing loss in the conventional range occurs only in the sound level group of 90 to 94 dB (A) l_eq without attaining any social importance. The tests show that, if the noise-level 90 dB (A) leq is not exceeded, no noise-induced hearing impairments involving social hearing loss are to be observed. Thus we assume that an auditory risk criterion of 85 dB (A) l_eq is sufficient to prevent hearing loss of any social importance.     

Noise characterization of “effective quiet” areas on a U.S. Navy aircraft carrier

The purpose of this investigation was to characterize noise levels in spaces designated as “effective quiet” areas on a U.S. Navy aircraft carrier. Noise dosimetry samples were collected in 15 designated spaces, representing 15 noise measurements, while at-sea during airwing carrier qualifications. Equivalent sound level (L_eq) measurements were collected during flight operations (L_{eq (flt ops)}), non-flight operations (L_{eq (non-flt ops)}), and over 24-hr periods (L_{eq (24-hr)}). These data were compared to the 70 dBA American Conference of Governmental Industrial Hygienists (ACGIH^®) Threshold Limit Value (TLV^®) for “effective quiet” areas intended for temporary threshold shift recovery when personnel live and work in a potentially noise hazardous environment for periods greater than 24?hr. The monitored areas were selected based on personnel occupancy/use during off-duty time periods. Areas were classified by either (1) leisure areas that included mess (eating areas), gyms, lounges, an internet cafe, and the fantail social area or (2) berthing (sleeping) areas. The L_eq measurements in decibels “A” weighted (dBA) were compared to determine significant differences between L_{eq (flt ops)}, L_{eq (non-flt ops)}, and L_{eq (24-hr)} and were compared between leisure area and berthing area. Measured noise levels according to time period ranged as follows: (1) L_{eq (24-hr)}: 70.8–105.4 dBA; (2) L_{eq (flt ops)}: 70–101.2 dBA; and (3) L_{eq (non-flt ops)}: 39.4–104.6 dBA. All area measurements over the 24-hr period and during flight operations and 46.7% of the areas during the non-flight operation time period exceeded the “effective quiet” 70 dBA ACGIH TLV. Mean L_eqs were 15 dBA higher during flight operations compared to non-flight operations in “effective quiet” areas (p?=?0.001). The L_eqs in leisure areas were significantly higher than berthing areas by approximately 21 dBA during non-flight operation periods (p?=?0.001). Results suggest noise levels in “effective quiet” areas frequented by aircraft carrier personnel during off-duty hours when at-sea may inhibit auditory recovery from occupational noise exposures that occur on-duty.     

Are the noise levels acceptable in a built environment like Hong Kong?

Governments all over the world have enacted environmental noise directives and noise control ordinances/acts to protect tranquility in residential areas. However, there is a lack of literature on the evaluation of whether the Acceptable Noise Levels (ANLs) stipulated in the directive/ordinance/act are actually achievable. The study aimed at measuring outdoor environmental noise levels in Hong Kong and identifying whether the measured noise levels are lower than the stipulated ANLs at 20 categories of residential areas. Data were gathered from a territory-wide noise survey. Outdoor noise measurements were conducted at 203 residential premises in urban areas, low-density residential areas, rural areas, and other areas. In total, 366 daytime hourly L_eq outdoor noise levels, 362 nighttime hourly L_eq outdoor noise levels, and 20 sets of daily, that is, 24 L_eq,1-h outdoor noise levels were recorded. The mean daytime L_eq,1-h values ranged 54.4-70.8 dBA, while the mean nighttime L_eq,1-h values ranged 52.6-67.9 dBA. When the measured noise levels were compared with the stipulated ANLs, only three out of the 20 categories of areas had outdoor noise levels below ANLs during daytime. All other areas (and all areas during nighttime) were found to have outdoor noise levels at or above ANLs.     

Noise exposure and hearing loss prevention programmes after 20 years of regulations in the United States

Objectives

To evaluate noise exposures and hearing loss prevention efforts in industries with relatively high rates of workers'' compensation claims for hearing loss.

Methods

Washington State workers'' compensation records were used to identify up to 10 companies in each of eight industries. Each company (n = 76) was evaluated by a management interview, employee personal noise dosimetry (n = 983), and employee interviews (n = 1557).

Results

Full‐shift average exposures were ⩾85 dBA for 50% of monitored employees, using Occupational Safety and Health Administration (OSHA) parameters with a 5 dB exchange rate (L_ave), but 74% were ⩾85 dBA using a 3 dB exchange rate (L_eq). Only 14% had L_ave ⩾90 dBA, but 42% had L_eq ⩾90 dBA. Most companies conducted noise measurements, but most kept no records, and consideration of noise controls was low in all industries. Hearing loss prevention programmes were commonly incomplete. Management interview scores (higher score = more complete programme) showed significant associations with percentage of employees having L_ave ⩾85 dBA and presence of a union (multiple linear regression; R² = 0.24). Overall, 62% of interviewed employees reported always using hearing protection when exposed. Protector use showed significant associations with percentage of employees specifically required to use protection, management score, and average employee time spent ⩾95 dBA (R² = 0.65).

Conclusions

The findings raise serious concerns about the adequacy of prevention, regulation, and enforcement strategies in the United States. The percentage of workers with excessive exposure was 1.5–3 times higher using a 3 dB exchange rate instead of the OSHA specified 5 dB exchange rate. Most companies gave limited or no attention to noise controls and relied primarily on hearing protection to prevent hearing loss; yet 38% of employees did not use protectors routinely. Protector use was highest when hearing loss prevention programmes were most complete, indicating that under‐use of protection was, in some substantial part, attributable to incomplete or inadequate company efforts.     

Long-term noise exposure and the risk for type 2 diabetes: A meta-analysis

Diabetes mellitus is one of the leading causes for disability and mortality in modern societies. Apart from personal factors its incidence might be influenced by environmental risks such as air pollution and noise. This paper reports a systematic review and meta-analysis on the risk for type 2 diabetes due to long-term noise exposure. Electronic searches in MEDLINE, EMBASE and the Internet yielded 9 relevant studies (5 for residential and 4 for occupational exposure). They were checked against a predefined list of safeguards against bias producing individual quality scores, which were then fed to MetaXL to conduct a quality effects meta-analysis. People exposed at their homes to roughly L_den > 60 dB had 22% higher risk (95% confidence interval [CI]: 1.09-1.37) for type 2 diabetes in comparison to those exposed to L_den < 64 dB; when studies reporting contentious exposure categories were excluded, there was still 19% risk (95% CI: 1.05-1.35) for L_den = 60-70 dB versus L_den < 60 dB. In occupational environment there was not significant risk (relative risk [RR] = 0.91, 95% CI: 0.78-1.06) for < 85 dB versus >85 dB. There was no heterogeneity in the two groups (I² = 0.00). The results should be interpreted with caution due to methodological discrepancies across the studies; however, they are indicative of the close links that noise pollution might have not only to cardiovascular diseases but to endocrine dysfunction as well.     

Association between Ambient Noise Exposure and School Performance of Children Living in An Urban Area: A Cross-Sectional Population-Based Study

Most of the studies investigating the effects of the external noise on children’s school performance have concerned pupils in schools exposed to high levels due to aircraft or freeway traffic noise. However, little is known about the consequences of the chronic ambient noise exposure at a level commonly encountered in residential urban areas. This study aimed to assess the relationship between the school performance of 8- to 9-year-old-children living in an urban environment and their chronic ambient noise exposure at home and at school. The children’s school performances on the national standardized assessment test in French and mathematics were compared with the environmental noise levels. Children’s exposure to ambient noise was calculated in front of their bedrooms (L_den) and schools (L_Aeq,day) using noise prediction modeling. Questionnaires were distributed to the families to collect potential confounding factors. Among the 746 respondent children, 586 were included in multilevel analyses. On average, the L_Aeq,day at school was 51.5 dB (SD= 4.5 dB; range = 38–58 dB) and the outdoor L_den at home was 56.4 dB (SD= 4.4 dB; range = 44–69 dB). L_Aeq,day at school was associated with impaired mathematics score (p = 0.02) or impaired French score (p = 0.01). For a + 10 dB gap, the French and mathematics scores were on average lower by about 5.5 points. L_den at home was significantly associated with impaired French performance when considered alone (p < 10⁻³) and was borderline significant when the combined home-school exposure was considered (p = 0.06). The magnitude of the observed effect on school performance may appear modest, but should be considered in light of the number of people who are potentially chronically exposed to similar environmental noise levels.     

Surveillance of noise exposure in the Danish workplace: a baseline survey

Aims: To evaluate an epidemiological approach to a national noise hazard surveillance strategy, and report current exposure levels in the Danish workplace.

Methods: A study base of 840 companies in 10 selected high risk industries in the largest county in Denmark was identified from a national register. Noise exposure was measured among manual workers recruited from a random sample of workplaces in each industry. For reference, financial companies and a sample of residents were investigated according to the same protocol. The A-weighted equivalent sound level (L_Aeq) for a full shift was measured by portable dosimeters worn by 830 workers employed at 91 workplaces (67% of 136 eligible companies).

Results: The epidemiological design proved feasible and established a baseline for future noise surveillance. Substantial resources were needed to motivate workplaces to enlist and the final participation rate was less than optimal (66.9%). The L_{Aeq (8)} values in the selected industries were highly elevated (mean 83.7 dB(A) (95% CI 83.3 to 84.1) in comparison with residents and office workers (mean 69.9 dB(A), 95% CI 68.8 to 71.0). Some 50% of the workers were exposed to more than 85 dB(A) and some 20% to more than 90 dB(A) in several industries.

Conclusion: Noise levels in Danish high risk industries remain high. A substantial proportion of workers are exposed to noise levels above the current threshold limit of 85 dB(A). Ongoing surveillance of noise exposure using full shift dosimetry of workers in random samples of workplaces most at risk to high noise levels may help reinforce preventive measures. Such a programme would benefit from compulsory workplace participation.

     

Associations between Nighttime Traffic Noise and Sleep: The Finnish Public Sector Study

Background: Associations between traffic noise and sleep problems have been detected in experimental studies, but population-level evidence is scarce.Objectives: We studied the relationship between the levels of nighttime traffic noise and sleep disturbances and identified vulnerable population groups.Methods: Noise levels of nighttime–outdoor traffic were modeled based on the traffic intensities in the cities of Helsinki and Vantaa, Finland. In these cities, 7,019 public sector employees (81% women) responded to postal surveys on sleep and health. We linked modeled outdoor noise levels to the residences of the employees who responded to the postal survey. We used logistic regression models to estimate associations of noise levels with subjectively assessed duration of sleep and symptoms of insomnia (i.e., difficulties falling asleep, waking up frequently during the night, waking up too early in the morning, nonrestorative sleep). We also used stratified models to investigate the possibility of vulnerable subgroups.Results: For the total study population, exposure to levels of nighttime–outside (L_{night, outside}) traffic noise > 55 dB was associated with any insomnia symptom ≥ 2 nights per week [odds ratio (OR) = 1.32; 95% confidence interval (CI): 1.05, 1.65]. Among participants with higher trait anxiety scores, which we hypothesized were a proxy for noise sensitivity, the ORs for any insomnia symptom at exposures to L_{night, outside} traffic noises 50.1–55 dB and > 55 dB versus ≤ 45 dB were 1.34 (95% CI: 1.00, 1.80) and 1.61 (95% CI: 1.07, 2.42), respectively.Conclusions: Nighttime traffic noise levels > 50 dB L_{night, outside} was associated with insomnia symptoms among persons with higher scores for trait anxiety. For the total study population, L_{night, outside} > 55 dB was positively associated with any symptoms.     

Transportation noise exposure and cardiovascular mortality: a nationwide cohort study from Switzerland

Most studies published to date consider single noise sources and the reported noise metrics are not informative about the peaking characteristics of the source under investigation. Our study focuses on the association between cardiovascular mortality in Switzerland and the three major transportation noise sources—road, railway and aircraft traffic—along with a novel noise metric termed intermittency ratio (IR), expressing the percentage contribution of individual noise events to the total noise energy from all sources above background levels. We generated Swiss-wide exposure models for road, railway and aircraft noise for 2001. Noise from the most exposed façade was linked to geocodes at the residential floor height for each of the 4.41 million adult (>30 y) Swiss National Cohort participants. For the follow-up period 2000–2008, we investigated the association between all noise exposure variables [L_den(Road), L_den(Rail), L_den(Air), and IR at night] and various cardiovascular primary causes of death by multipollutant Cox regression models adjusted for potential confounders including NO₂. The most consistent associations were seen for myocardial infarction: adjusted hazard ratios (HR) (95% CI) per 10 dB increase of exposure were 1.038 (1.019–1.058), 1.018 (1.004–1.031), and 1.026 (1.004–1.048) respectively for L_den(Road), L_den(Rail), and L_den(Air). In addition, total IR at night played a role: HRs for CVD were non-significant in the 1st, 2nd and 5th quintiles whereas they were 1.019 (1.002–1.037) and 1.021 (1.003–1.038) for the 3rd and 4th quintiles. Our study demonstrates the impact of all major transportation noise sources on cardiovascular diseases. Mid-range IR levels at night (i.e. between continuous and highly intermittent) are potentially more harmful than continuous noise levels of the same average level.     

某热电厂锅炉磨煤机房噪声治理效果评价及缺陷分析

目的对某热电厂锅炉磨煤机房噪声治理效果进行评价,分析存在的缺陷,探讨缺陷的成因,以提高噪声治理的效果。方法采用现场职业卫生调查和噪声测量进行分析和综合评价。结果噪声治理后,车间内噪声声级由100.9 dB(A)下降为96.8 dB(A),最优磨煤机隔声罩的隔声量为17.5～19.4 dB(A),平均为18.45 dB(A),没有达到治理目标值。经调查,车间内的主要声源为锅炉磨煤机筒体,次要声源为锅炉磨煤机电机,该厂除了对12台锅炉磨煤机的筒体和1台锅炉磨煤机的电机设置了局部隔声罩外,未采取其他降噪措施。结论该厂锅炉磨煤机房噪声治理方案有缺陷,导致治理效果不理想。