Exposures to transit and other sources of noise among New York City residents

Toward a better understanding of nonoccupational sound exposures and associated health impacts: Methods of the Apple Hearing Study

Globally, noise exposure from occupational and nonoccupational sources is common, and, as a result, noise-induced hearing loss affects tens of millions of people. Occupational noise exposures have been studied and regulated for decades, but nonoccupational sound exposures are not well understood. The nationwide Apple Hearing Study, launched using the Apple research app in November 2019 (Apple Inc., Cupertino, CA), is characterizing the levels at which participants listen to headphone audio content, as well as their listening habits. This paper describes the methods of the study, which collects data from several types of hearing tests and uses the Apple Watch noise app to measure environmental sound levels and cardiovascular metrics. Participants, all of whom have consented to participate and share their data, have already contributed nearly 300 × 10⁶ h of sound measurements and 200 000 hearing assessments. The preliminary results indicate that environmental sound levels have been higher, on average, than headphone audio, about 10% of the participants have a diagnosed hearing loss, and nearly 20% of the participants have hearing difficulty. The study's analyses will promote understanding of the overall exposures to sound and associated impacts on hearing and cardiovascular health. This study also demonstrates the feasibility of collecting clinically relevant exposure and health data outside of traditional research settings.

Online, Asynchronous Hearing Education and Research Project for Ethnically Diverse Adolescents via Interprofessional Collaboration and Electronic Service-Learning During the COVID-19 Pandemic: A Pilot Study on the Needs and Challenges

Purpose This study discusses the creation of an online, asynchronous presentation to educate adolescents about prevention of noise-induced hearing loss (NIHL) through interprofessional collaborations and electronic service-learning (eSL) during the COVID-19 pandemic. Method The Hearing Education and Research (HEAR) presentation, which included activities and videos to educate a group of ethnically diverse adolescents (n = 100) on NIHL, was created by 11 doctor of audiology (AuD) students through online collaborations toward course-related eSL requirements. Adolescents responded to a baseline survey to assess hearing health-related behaviors prior to reviewing the presentation. A postprogram survey was administered 1 week after the presentation to assess change in knowledge and attitudes toward NIHL prevention. Online collaborations with schoolteachers helped with project implementation. Postreflection papers written by AuD students regarding the eSL activities were analyzed. Lastly, suggestions from a focus group of educators were included that highlight the role of interprofessional collaborations to enhance school-based hearing conservation opportunities. Results The HEAR presentation resulted in changes in knowledge about NIHL among the adolescents. Postreflection papers by the AuD students indicated that the eSL activity served as a high-impact pedagogical assignment, especially during the academic challenges of the pandemic. Feedback from a focus group of schoolteachers helped outline ideas for future implementation of sustainable hearing conservation programs in school settings. Conclusion The pilot data collected in this study serve as a proof of concept for future hearing conservation projects in school-based settings via interprofessional collaborations and by engaging university students via eSL.

Loud Music and Leisure Noise Is a Common Cause of Chronic Hearing Loss, Tinnitus and Hyperacusis

High sound levels capable of permanently damaging the ear are experienced not only in factories and war zones but in concert halls, nightclubs, sports stadiums, and many other leisure environments. This review summarizes evidence that loud music and other forms of "leisure noise" are common causes of noise-induced hearing loss, tinnitus, and hyperacusis, even if audiometric thresholds initially remain within clinically normal limits. Given the huge global burden of preventable noise-induced hearing loss, noise limits should be adopted in a much broader range of settings, and education to promote hearing conservation should be a higher public health priority.

Predicting Fine Spatial Scale Traffic Noise Using Mobile Measurements and Machine Learning

Environmental noise has been associated with a variety of health endpoints including cardiovascular disease, sleep disturbance, depression, and psychosocial stress. Most population noise exposure comes from vehicular traffic, which produces fine-scale spatial variability that is difficult to characterize using traditional fixed-site measurement techniques. To address this challenge, we collected A-weighted, equivalent noise (LAeq in decibels, dB) data on hour-long foot journeys around 16 locations throughout Long Beach, California and trained four machine learning models, linear regression, random forest, extreme gradient boosting, and a neural network, to predict noise with 20 m resolution. Input variables to the models included traffic metrics, road network features, meteorological conditions, and land use type. Among all machine learning models, extreme gradient boosting had the best results in validation tests (leave-one-route-out R² = 0.71, root mean square error (RMSE) of 4.54 dB; 5-fold R² = 0.96, RMSE of 1.8 dB). Local traffic volume was the most important predictor of noise; road features, land use, and meteorology including humidity, temperature, and wind speed also contributed. We show that a novel, on-foot mobile noise measurement method coupled with machine learning approaches enables highly accurate prediction of small-scale spatial patterns in traffic-related noise over a mixed-use urban area.

Risk of noise-induced hearing loss due to recreational sound: Review and recommendations

This review was conducted to address three questions related to recreational sound exposure: (1) what criteria are used to determine noise exposure limits, (2) are there differences in the risk of hearing loss from occupational noise versus recreational sound, and (3) what is an appropriate exposure limit for recreational sound? For the first question, most standards specify an 8-h occupational noise exposure limit (L_EX) of 85 dBA. This limit assumes that some workers exposed at the limit will develop hearing loss. To eliminate the risk of hearing loss, a 24-h equivalent continuous level (L_EQ24h) limit of 70 dBA is appropriate. For the second question, there is some evidence that the effects of occupational noise on hearing may be worse than energetically equivalent recreational sound. Limits developed for noise are nevertheless applicable to recreational sound, and use of existing statistical models to predict hearing loss from recreational sound is appropriate, with the caveat that these models are limited to durations ≤40 years. For the third question, a recreational sound limit of 80 dBA L_EX, equivalent to a 75 dBA L_EQ24h, will virtually eliminate the risk of recreationally induced hearing loss in adults. Lower limits may be warranted for vulnerable or susceptible individuals.

The Relationship between Sound and Amenities of Transit-Oriented Developments

Experts in diverse fields have investigated sound in cities throughout the United States. This research aims to examine sound levels and determine its contributors at the transit-oriented development (TOD) station and neighborhood levels by studying selected Dallas Area Rapid Transit (DART) light rail stations. A multilevel analysis was performed to model the likelihood of TOD stations and neighborhoods affecting sound levels, controlling for station amenities, socio-demographics and built environment characteristics. Sound measurements were sampled in three time intervals with 15 min sampling over weekdays and weekends at TOD and non-TOD stations by a type II SPL meter that was mounted on a small camera tripod at a height of 1.5 m, at a distance of 1.5 m from rails and curbs. The research team found that amenities, built environmental characteristics, and neighborhood features have significant implications on sound levels at both the TOD station and the neighborhood level, which affects quality of life (QoL). TOD stations that include more amenities have a greater level of significance on sound levels. Additionally, neighborhoods with a pervasive street grid configuration, public facilities, and built environment densities are significantly associated with a likelihood of high sound levels. Conversely, higher population densities and intersection densities decrease the likelihood of a high sound level environment. These patterns provide an arena for transportation, urban, and environmental planning and policymaking to generate transformative solutions and policies.

Measuring environmental noise from airports, oil and gas operations, and traffic with smartphone applications: laboratory and field trials

Environmental noise from sources such as traffic, airports, and oil and gas (O&G) operations is associated with nuisance and health concerns. Smartphones with external microphones have been recommended for environmental noise monitoring and may be useful tools for citizen science, but are not validated against reference methods. We evaluated laboratory performance of three smartphone/application (app) configurations recommended for environmental noise measurement. Two smartphone/app configurations were also compared to a reference sampler, a type 1 sound level meter (SLM) at ten outdoor sites with traffic, airport, and O&G noise. To evaluate performance, we compared the mean squared error, variance, bias, and Krippendorff's Alpha by smartphone/app combination and testing location for both audible (A-weighted) and low-frequency (C-weighted) noise. We observed that laboratory measurements were in strong agreement with a reference sampler. The field A-weighted noise level results had strong agreement with the SLM at several outdoor sites, but our C-weighted noise results ranged from moderate to substantial agreement. For our tested configurations, we find that smartphones with external microphones are reliable proxies for measuring A- and C-weighted noise in a laboratory setting. Outdoor performance depends on noise source type, weighting, and precision and accuracy needs of the investigation.

Residential noise from nearby oil and gas well construction and drilling

Public concern about oil and gas (O&G) operations in residential areas is substantial. Noise from construction and drilling related to O&G operations may be greater than other phases of O&G operations; yet the impacts of audible and low-frequency noise during these operations are not extensively explored nor the effects on health well understood. This study documents the noise levels at a multi-well O&G well pad during construction and drilling in a residential area in Colorado. A-weighted (dBA) and C-weighted (dBC) noise measurements were collected at four locations during development over a 3-month period. The maximum 1-min equivalent continuous sound levels over a 1-month period were 60.2 dBA and 80.0 dBC. Overall, 41.1% of daytime and 23.6% of nighttime dBA 1-min equivalent continuous noise measurements were found to exceed 50 dBA, and 97.5% of daytime and 98.3% of nighttime measurements were found to exceed 60 dBC. Noise levels exceeding 50 dBA or 60 dBC may cause annoyance and be detrimental to health; thus, these noise levels have the potential to impact health and noise levels and associated health effects warrant further investigation.

Auditory central gain compensates for changes in cochlear output after prolonged low-level noise exposure

Remarkably, the central auditory system can modify the strength of its sound-evoked neural response based on prior acoustic experiences, a phenomenon referred to as central gain. Gain changes are well documented following traumatic noise exposure, but much less is known about central gain dynamics following prolonged exposure to low-level noise, a common acoustic experience in many urban and work environments. We recently reported that the neural output of the cochlea is reduced, while gain was enhanced in the inferior colliculus (IC) following a 5-week exposure to 75 dB noise. To determine if similar effects were present at even lower intensities, we exposed rats to a 65 dB noise expecting to see little to no change in the cochlea or IC. The exposure had little effect on distortion product otoacoustic emissions and did not cause any hair cell loss. However, the amplitude of the CAP, which reflects the neural output of cochlea, was depressed by 50-75%. Surprisingly, neural responses from the IC were enhanced up to 70%, mainly at frequencies within the noise exposure band. One-week post-exposure, CAP amplitudes returned to normal at frequencies within or above the exposure band, whereas responses evoked by frequencies below the exposure band were enhanced by more than 80%. In contrast, IC responses below the exposure frequency were depressed 10-20% whereas responses within the exposure frequency band were enhanced 10-20%. Thus, the central auditory system dynamically up- and down-regulates its gain to maintain supra-threshold neural responses within a narrow homeostatic range; a function that likely contributes to the prevention of sounds from being perceived as muffled or too loud.

Hearing loss, lead (Pb) exposure, and noise: a sound approach to ototoxicity exploration

To determine the state of the research on ototoxic properties of Pb, evaluate possible synergistic effects with concurrent noise exposure, and identify opportunities to improve future research, we performed a review of the peer-reviewed literature to identify studies examining auditory damage due to Pb over the past 50 years. Thirty-eight studies (14 animal and 24 human) were reviewed. Of these, 24 suggested potential ototoxicity due to Pb exposure, while 14 found no evidence of ototoxicity. More animal studies are needed, especially those investigating Pb exposure levels that are occupationally and environmentally relevant to humans. Further investigations into potential interactions of Pb in the auditory system with other hazards and compounds that elicit ototoxicity are also needed in animal models. To better assess the effects of Pb exposure on the human auditory system and the possibility of a synergism with noise, future epidemiological studies need to carefully consider and address four main areas of uncertainty: (1) hearing examination and quantification of hearing loss, (2) Pb exposure evaluation, (3) noise exposure evaluation, and (4) the personal characteristics of those exposed. Two potentially confounding factors, protective factors and mixtures of ototoxicants, also warrant further exploration.

Development of a Job Exposure Matrix for Noise in the Swedish Soft Tissue Paper Industry

Objectives

Noise exposure is a common occupational hazard, but has not been sufficiently characterized in paper mills. We developed a job-exposure matrix (JEM) for noise exposure for use in estimating exposures among Swedish soft tissue paper mill workers.

Methods

We used a combination of area and personal dosimetry noise exposure measurements made at four soft tissue paper mills by industry and research staff between 1977 and 2013 to estimate noise exposures by department, location, and job title. We then utilized these estimates, in conjunction with information on process and facility changes and use of hearing protection collected via focus groups, to create a seven-category, semi-quantitative JEM for all departments, locations, and job titles spanning the years 1940–2010.

Results

The results of the 1157 area and personal dosimetry noise measurements indicated that noise levels have generally declined in Swedish paper mills over time, though these changes have been neither uniform nor monotonic within or across the four mills. Focus group results indicated that use of hearing protection has generally increased over time. The noise JEM totals 1917 cells, with each cell representing a unique combination of operation, job title, and single year. We estimated that ~50% of workers at the four mills assessed were exposed at or above the Swedish 8-h average noise exposure limit of an 85 dBA at the conclusion of the study period in 2010.

Conclusions

Our results highlight the continuing need for hearing loss prevention and noise control efforts at these and similar mills, and the completed JEM now represents a tool for use in epidemiological studies of noise-related health outcomes.

The role of traffic noise on the association between air pollution and children's lung function

Although it has been shown that traffic-related air pollution adversely affects children's lung function, few studies have examined the influence of traffic noise on this association, despite both sharing a common source. Estimates of noise exposure (L_dn, dB), and freeway and non-freeway emission concentrations of oxides of nitrogen (NO_x, ppb) were spatially assigned to children in Southern California who were tested for forced vital capacity (FVC, n=1345), forced expiratory volume in 1s, (FEV_1, n=1332), and asthma. The associations between traffic-related NO_x and these outcomes, with and without adjustment for noise, were examined using mixed effects models. Adjustment for noise strengthened the association between NO_x and reduced lung function. A 14.5mL (95% CI -40.0, 11.0mL) decrease in FVC per interquartile range (13.6 ppb) in freeway NO_x was strengthened to a 34.6mL decrease after including a non-linear function of noise (95% CI -66.3, -2.78mL). Similarly, a 6.54mL decrease in FEV₁ (95% CI -28.3, 15.3mL) was strengthened to a 21.1mL decrease (95% CI -47.6, 5.51) per interquartile range in freeway NO_x. Our results indicate that where possible, noise should be included in epidemiological studies of the association between traffic-related air pollution on lung function. Without taking noise into account, the detrimental effects of traffic-related pollution may be underestimated.

Analysis of Subway Interior Noise at Peak Commuter Time

Background and Objectives

Although mass transit systems are convenient and efficient for urban people, little attention has been paid to the potential hearing hazard from their noise. The purpose of the current study was to measure and analyze levels of subway interior noise at peak commuter times and to provide information about commuters’ daily dose of noise exposure.

Materials and Methods

To measure the subway interior noise, nine subway lines inside Seoul (i.e., lines 1-9) and six lines surrounding the capital city area (i.e., Central, Bundang, Sinbundang, Incheon, Gyeongui, and Gyeongchun) were chosen. The noise was measured and recorded by a sound level meter for two-hour periods in the morning and evening.

Results

1) In the LZeq analysis, the average noise level of all 15 lines was 72.78 dB; the maximum and minimum noise levels were 78.34 and 62.46 dB, respectively. The average noise level of the nine lines inside Seoul was 73.45 dB, which was 1.68-dB louder than that of the six lines surrounding the capital city area. 2) Based on the LZeq analysis of 33 measured frequencies, 12.5 Hz was the highest frequency and 20,000 Hz was the lowest. 3) There was no remarkable difference in the level of subway interior noise between morning and evening peak commuter times.

Conclusions

We concluded that the level of subway interior noise was not loud enough for commuters to incur noise-induced hearing loss. Regardless, environmental noise control efforts in the subway system might be needed for commuters who take a subway every day.

Economic Impact of Hearing Loss and Reduction of Noise-Induced Hearing Loss in the United States

PURPOSE

Hearing loss (HL) is pervasive and debilitating, and noise-induced HL is preventable by reducing environmental noise. Lack of economic analyses of HL impacts means that prevention and treatment remain a low priority for public health and environmental investment.

METHOD

This article estimates the costs of HL on productivity by building on established estimates for HL prevalence and wage and employment differentials between those with and without HL.

RESULTS

We estimate that HL affects more than 13% of the working population. Not all HL can be prevented or treated, but if the 20% of HL resulting from excessive noise exposure were prevented, the economic benefit would be substantial-we estimate a range of $58 billion to $152 billion annually, with a core estimate of $123 billion. We believe this is a conservative estimate, because consideration of additional costs of HL, including health care and special education, would likely further increase the benefits associated with HL prevention.

CONCLUSION

HL is costly and warrants additional emphasis in public and environmental health programs. This study represents an important first step in valuing HL prevention-in particular, prevention of noise-induced HL-where new policies and technologies appear promising.

The influence of subway station design on noise levels

OBJECTIVES/HYPOTHESIS

To investigate the impact of subway station design on platform noise levels.

STUDY DESIGN

Observational.

METHODS

Continuous A-weighted decibel (dBA) sound levels were recorded in 20 New York City subway stations, where trains entered on either a straight track or curved track in 10 stations each. Equivalent continuous noise levels (L_eq ) at various locations on the boarding platform (inbound end, midplatform, and outbound end) during train entry and exit were compared between the straight and curved stations in broadband as well as narrow one-third octave bands.

RESULTS

Overall, curved stations trended louder than straight stations, although the difference in broadband L_eq did not reach statistical significance (curve, 83.4 dBA; straight, 82.6 dBA; P = .054). Noise levels were significantly louder at the inbound end of the platform during train entry (inbound, 89.7 dBA; mid, 85.5 dBA; outbound, 78.7 dBA; P < .001) and at the outbound end during train exit (inbound, 79.7 dBA; mid, 85.3 dBA; outbound, 89.1 dBA; P < .001). Narrow band analysis showed that curved stations were significantly louder than straight stations at 100 Hz and high frequencies from 8 to 20 kHz. Peak impact levels ranged from 104 to 121 dBA.

CONCLUSIONS

Curved stations have a different noise profile compared to straight stations and are significantly louder than straight stations at high frequencies. Designing stations with straight tracks within the platform can help reduce commuter noise exposure.

LEVEL OF EVIDENCE

NA Laryngoscope, 127:1169-1174, 2017.

Injury Risk and Noise Exposure in Firefighter Training Operations

INTRODUCTION

Firefighters have high rate of injuries and illnesses, as well as exposures to high levels of noise. This study explored the relationship between noise exposure and injury among firefighters.

METHODS

We recruited firefighters undergoing vehicle extrication and structural collapse emergency response training at a highly realistic training facility. Demographics, health status, body mass index (BMI), and history of serious injuries (i.e. injuries requiring first aid treatment, treatment in a medical clinic or office, or treatment at a hospital) were assessed at baseline, and daily activities, injury events, and near misses were assessed daily via surveys. Participants' noise exposures were monitored for one 24-h period using noise dosimeters. We used a mixed-effects logistic regression model to estimate the odds of injury events and near misses associated with noise exposure as an independent variable.

RESULTS

Of 56 subjects, 20 (36%) reported that they had ever suffered a serious injury during firefighting activities, and 9 (16%) reported a serious injury within the past year. We estimated rates of 6.6 lifetime serious injuries per 100 FTE 16.1 serious injuries per 100 FTE within the past year. Our models indicated a significant increase in injury events and near misses among those with higher BMI, and as well as a dose-response relationship between near misses/injuries and increasing noise levels. Noise levels >90 dBA in the 30 min prior to time of injury or near miss were associated with substantially increased odds ratios for injury or near miss. Our models further indicated that perceived job demands were significantly associated with increased risk of injury or near miss.

CONCLUSION

Our results suggest that noise exposures may need to be incorporated into injury prevention programs for firefighters to reduce injuries among this high-risk occupational group.

Valuing Quiet: An Economic Assessment of U.S. Environmental Noise as a Cardiovascular Health Hazard

INTRODUCTION

Environmental noise pollution increases the risk for hearing loss, stress, sleep disruption, annoyance, and cardiovascular disease and has other adverse health impacts. Recent (2013) estimates suggest that more than 100 million Americans are exposed to unhealthy levels of noise. Given the pervasive nature and significant health effects of environmental noise pollution, the corresponding economic impacts may be substantial.

METHODS

This 2014 economic assessment developed a new approach to estimate the impact of environmental noise on the prevalence and cost of key components of hypertension and cardiovascular disease in the U.S. By placing environmental noise in context with comparable environmental pollutants, this approach can inform public health law, planning, and policy. The effects of hypothetical national-scale changes in environmental noise levels on the prevalence and corresponding costs of hypertension and coronary heart disease were estimated, with the caveat that the national-level U.S. noise data our exposure estimates were derived from are >30 years old.

RESULTS

The analyses suggested that a 5-dB noise reduction scenario would reduce the prevalence of hypertension by 1.4% and coronary heart disease by 1.8%. The annual economic benefit was estimated at $3.9 billion.

CONCLUSIONS

These findings suggest significant economic impacts from environmental noise-related cardiovascular disease. Given these initial findings, noise may deserve increased priority and research as an environmental health hazard.

ICBEN review of research on the biological effects of noise 2011-2014

The mandate of the International Commission on Biological Effects of Noise (ICBEN) is to promote a high level of scientific research concerning all aspects of noise-induced effects on human beings and animals. In this review, ICBEN team chairs and co-chairs summarize relevant findings, publications, developments, and policies related to the biological effects of noise, with a focus on the period 2011-2014 and for the following topics: Noise-induced hearing loss; nonauditory effects of noise; effects of noise on performance and behavior; effects of noise on sleep; community response to noise; and interactions with other agents and contextual factors. Occupational settings and transport have been identified as the most prominent sources of noise that affect health. These reviews demonstrate that noise is a prevalent and often underestimated threat for both auditory and nonauditory health and that strategies for the prevention of noise and its associated negative health consequences are needed to promote public health.

Street-level noise in an urban setting: assessment and contribution to personal exposure

BACKGROUND

The urban soundscape, which represents the totality of noise in the urban setting, is formed from a wide range of sources. One of the most ubiquitous and least studied of these is street-level (i.e., sidewalk) noise. Mainly associated with vehicular traffic, street level noise is hard to ignore and hard to escape. It is also potentially dangerous, as excessive noise from any source is an important risk factor for adverse health effects. This study was conducted to better characterize the urban soundscape and the role of street level noise on overall personal noise exposure in an urban setting.

METHODS

Street-level noise measures were obtained at 99 street sites located throughout New York City (NYC), along with data on time, location, and sources of environmental noise. The relationship between street-level noise measures and potential predictors of noise was analyzed using linear and logistic regression models, and geospatial modeling was used to evaluate spatial trends in noise. Daily durations of street-level activities (time spent standing, sitting, walking and running on streets) were estimated via survey from a sample of NYC community members recruited at NYC street fairs. Street-level noise measurements were then combined with daily exposure durations for each member of the sample to estimate exposure to street noise, as well as exposure to other sources of noise.

RESULTS

The mean street noise level was 73.4 dBA, with substantial spatial variation (range 55.8-95.0 dBA). Density of vehicular (road) traffic was significantly associated with excessive street level noise levels. Exposure duration data for street-level noise and other common sources of noise were collected from 1894 NYC community members. Based on individual street-level exposure estimates, and in consideration of all other sources of noise exposure in an urban population, we estimated that street noise exposure contributes approximately 4% to an average individual's annual noise dose.

CONCLUSIONS

Street-level noise exposure is a potentially important source of overall noise exposure, and the reduction of environmental sources of excessive street- level noise should be a priority for public health and urban planning.

Indoor noise exposure at home: a field study in the family of urban schoolchildren

This article aims at evaluating indoor noise levels at home and investigating the factors that may influence their variability. An 8-day noise measurement campaign was conducted in the homes of 44 schoolchildren attending the public primary schools of Besançon (France). The presence of the inhabitants in the dwelling and the noisy events occurring indoors and outdoors was daily collected using a time-location-activity diary (TLAD); 902 time periods were analyzed. The indoor noise level increased significantly with the outdoor noise level, along with the duration of the presence or level of activity of the inhabitants at home. However, this effect may vary according to the period of day and the day of the week. Moreover, a significant part of the day and evening indoor noise level variability was explained when considering the TLAD variables: 46% and 45% in the bedroom, 54% and 39% in the main room, respectively. Our results highlight the complexity of the indoor environment in the dwellings of children living in an urban area. Combining the inhabitant presence and indoor noise source descriptors with outdoor noise levels and other dwelling or inhabitant characteristics could improve large-scale epidemiological studies. However, additional efforts are still needed, particularly during the night period.

Temporal and spatial variability of traffic-related noise in the City of Toronto, Canada

The majority of studies that assessed population-level exposure to traffic-related noise were conducted in European countries and less is known about the exposure to traffic noise in North America, particularly in Canadian cities. This study explored the temporal and spatial variability of traffic noise in the City of Toronto, the largest city in Canada. We conducted two cycles of intensive field measurement campaign to collect real-time measurements of traffic noise at 554 locations across Toronto between June 2012 and January 2013. At each site, we collected measurements for a period of 30 min during daytime. Repeated measurements were made in cycle two at 62 locations randomly selected from cycle one, which exhibited high correlation (Pearson's correlation coefficient (r): 0.79). In addition, continuous measurements of noise were recorded for seven days at ten sites. We observed that noise variability was predominantly spatial in nature, rather than temporal: spatial variability accounted for 60% of the total observed variations in traffic noise. Traffic volume, length of arterial road, and industrial area were three most important variables, explaining the majority of the spatial variability of noise (R(2)=0.68 to 0.74, depending on the cycle). In comparison to the 16-h equivalent sound level guideline for outdoor locations set out by the Ministry of the Environment of the Province of Ontario, 80% of our sampled locations exceeded this guideline (i.e. 55 dBA,16 h). These findings suggested ubiquitous traffic noise exposure across Toronto and that noise variability was explained mostly by spatial characteristics.

Environmental noise pollution in the United States: developing an effective public health response

BACKGROUND

Tens of millions of Americans suffer from a range of adverse health outcomes due to noise exposure, including heart disease and hearing loss. Reducing environmental noise pollution is achievable and consistent with national prevention goals, yet there is no national plan to reduce environmental noise pollution.

OBJECTIVES

We aimed to describe some of the most serious health effects associated with noise, summarize exposures from several highly prevalent noise sources based on published estimates as well as extrapolations made using these estimates, and lay out proven mechanisms and strategies to reduce noise by incorporating scientific insight and technological innovations into existing public health infrastructure.

DISCUSSION

We estimated that 104 million individuals had annual LEQ(24) levels > 70 dBA (equivalent to a continuous average exposure level of >70 dBA over 24 hr) in 2013 and were at risk of noise-induced hearing loss. Tens of millions more may be at risk of heart disease, and other noise-related health effects. Direct regulation, altering the informational environment, and altering the built environment are the least costly, most logistically feasible, and most effective noise reduction interventions.

CONCLUSION

Significant public health benefit can be achieved by integrating interventions that reduce environmental noise levels and exposures into the federal public health agenda.

Assessment of Noise Exposure to Children: Considerations for the National Children's Study

Evidence has been accruing to indicate that young children are vulnerable to noise in their physical environment. A literature review identified that, in addition to hearing loss, noise exposure is associated with negative birth outcomes, reduced cognitive function, inability to concentrate, increased psychosocial activation, nervousness, feeling of helplessness, and increased blood pressure in children. While increasing attention has been given to the health effects of noise in children, research about noise exposure is sparse and often the measure of exposure is simply proximity to a noise source. The U.S. National Children's Study (NCS) provides a unique opportunity to investigate noise exposures to pregnant women and children using a number of assessment modalities at different life stages. Measurement of noise levels in homes and other environments, personal dosimetry measurements made over a period of days, and questionnaires addressing sources of noise in the environment, annoyance to noise, perceived noise level, use of head phones and ear buds, noisy activity exposures, and occupational exposures, are planned for evaluation within the NCS Vanguard pilot study. We describe the NCS planned approach to addressing noise exposure assessment in study visits over a child's lifetime.

Assessment of noise measurements made with a continuous monitoring in time

The World Health Organization has stated that hearing loss is one of the top 10 health problems worldwide and that noise-induced hearing loss is the leading occupational disease. This work evaluated the noise exposure levels of several job categories for 24-h periods over 7 days to determine the contribution of each microenvironment to total noise exposure. The noise exposure levels of 47 individuals were continuously measured using personal noise dosimeters in metropolitan Seoul, Korea. Participants ranged in age from 20 to 50 yr and represented eight occupational groups. Participants were asked to attach the noise dosimeters and complete a time-activity diary 24 h a day for 7 days. The average Leq 24 h,w among these individuals was 74 dBA, which ranged from 64 to 96 dBA. The average Leq 24 h,w was highest for Korean traditional music apprentices, followed by heavy equipment operators, firefighters, service workers, office workers, industrial hygienists, graduate and undergraduate students, and housewives (89, 77, 76, 76, 75, 71, 71, and 71 dBA, respectively, p < 0.001). 38 (80.9%) were exposed to noise levels greater than 70 dBA, which corresponds to the World Health Organization's exposure limit.

Estimation of permanent noise-induced hearing loss in an urban setting

The potential burden of noise-induced permanent threshold shift (NIPTS) in U.S. urban settings is not well-characterized. We used ANSI S3.44-1996 to estimate NIPTS for a sample of 4585 individuals from New York City (NYC) and performed a forward stepwise logistic regression analysis to identify predictors of NIPTS >10 dB. The average individual is projected to develop a small NIPTS when averaged across 1000-4000 Hz for 1- to 20-year durations. For some individuals, NIPTS is expected to be substantial (>25 dB). At 4000 Hz, a greater number of individuals are at risk of NIPTS from MP3 players and stereos, but risk for the greatest NIPTS is for those with high occupational and episodic nonoccupational (e.g., power tool use) exposures. Employment sector and time spent listening to MP3 players and stereos and participating in episodic nonoccupational activities associated with excessive noise levels increased the odds of NIPTS >10 dB at 4000 Hz for 20-year durations. Our results indicate that the risk of NIPTS may be substantial for NYC and perhaps other urban settings. Noise exposures from "noisy" occupational and episodic nonoccupational activities and MP3 players and stereos are important risk factors and should be a priority for public health interventions.