Mean Noise Level Research Articles

Comparative Study of Different Drills for Bone Drilling: A Systematic Approach.

Introduction:The performance of the drilling process depends on the characteristics of the drilling equipment and surgeon’s skill. To our knowledge, no research has focused on multi-parameter analysis of the dynamic behaviour of drills during the drilling process. This study aimed to characterise the physical changes and effects of different drills attached to a robotic arm during drilling of artificial bones in a standardised experimental setup.Material and Methods:Drilling processes using three brands of drills attached to a robotic arm were compared in terms of thrust force, vibration, noise level, speed deviation, and temperature. A standardised experimental setup was constructed, and measurement data were analysed statistically. Identical artificial bones were drilled 10 times with each drill.Results:Thrust force measurements, which varied through the cortex and medulla, showed expressive differences for each drill for maximum and mean values (p<0.001). Meaningful differences were obtained for mean vibration values and noise level (p<0.001). Speed variation measurements in drilling showed conspicuous differences with confident statistics (p<0.001). Induced temperature values were measured statistically for Drill 1, Drill 2, and Drill 3 as 78.38±11.49°C, 78.11±7.79°C, and 89.77±7.79°C, respectively.Conclusion:Thrust force and drill bit temperature were strongly correlated for each drill. Vibration values and noise level, which also had an influential relationship, were in the acceptable range for all experiments. Both thrust force and speed deviation information could be used to detect the drill bit status in the bone while drilling.

Noise level forecasts at 8–20 MHz and their use for morphological studies of ionospheric absorption variations at EKB ISTP SB RAS radar

In this paper, a method is described for using 8–20 MHz noise absorption effect for real time detecting radio wave absorption periods. The method is based on two empirical autoregression models of noise variations. The first (rough) prediction model is based on radar measurements of daily minimum noise variations averaged over 28-days with specially calculated weight coefficients. The second (fine) prediction model uses real-time scaling of rough model. The scaling is based on the comparison of this model with the experimental noise observations during previous 5 days. The models are based on the whole EKB ISTP SB RAS radar data set (2013–2018). The rough model allows one to estimate the boundary beyond which the noise variations can be associated with absorption periods. A joint analysis of simultaneous data on neighboring radar beams and at several frequencies reduces the detection errors, and allows one to identify noise absorption incidents with a higher degree of confidence. Use of the fine model allows us to estimate absorption. The technique is validated by frequency dependence of absorption during two-frequency measurements. The found frequency dependence has an average exponent of about −1.5, which is in good agreement with the literature data and the data obtained earlier in the analysis of solar X-ray flares. The use of the detection technique at EKB radar shows that the mode of vertical absorption at 10 MHz over noise absorption incidents is about 0.65 dB. Analysis of absorption of different amplitudes shows that low-intensity noise absorption incidents (0..1.3 dB) have slight local time dependence and mostly observed at north directions. For the strong noise absorption incidents (stronger than 1.3 dB) the analysis of local time dependence shown that the mean absorption level over all the noise absorption incidents correlates well with the mean noise level over all the available experiments, and usually is observed at every azimuth within the radar field of view.

Occupational Hazard Assessment in a Vegetable Oil Producing Industry, Southwestern Nigeria

Reportedly, 50 - 70% of current global labor force is exposed to poor working conditions. This study examined exposure and hazards of workers in a vegetable oil industry and the perceived health effects in Southwestern, Nigeria. A descriptive cross-sectional survey (including environmental monitoring) was employed to assess the workplace hazards and their perceived health effects on workers. The sampling covered 102 respondents across 15 departments within the industry. Data obtained were statistically analyzed using SPSS version 16. Common identified health and safety hazards were backache (17.6%), eye irritation (5.9%), breathing difficulty (6.9%), heat exhaustion (31.4%), bruises (2%), cuts and injuries (2%), and skin irritation (7.8%). Noise levels varied from section to section with the power plant recording the highest maximum mean noise level of 103.7dB though a lower mean noise level of 86.7dB was recorded for the office section. The noise level of 88.6dB was recorded at the boiler section; crushing floor had a noise level of 91.8dB at the work area while the office section had a lower noise level of 80.3dB. A noise level of 96.5dB was recorded at the Solvent Extraction Plant section; the office area had 78.2dB while agro laboratory and margarine section recorded 62.6dB and 73.3dB respectively. The study findings reveal that occupational health and safety in the workplace is inadequate with a wide range of hazards, physical, chemical, and ergonomic, which suggests implementation of stringent safety measures.

Impact of intraoperative noise measurement on the surgeon stress and patient outcomes. A prospective, controlled, single-center clinical trial with 664 patients

BackgroundThe impact of sound-activated noise meters to decrease the noise level in the operating room is not clear. The aim of this study was to determine whether a sound-activated, visual noise meter would decrease noise levels, decrease postoperative morbidity, and improve surgeons’ feelings of well-being. MethodsThis prospective, single-center study proceeded in 2 phases. First, sound levels were compared during a 6-month period with noise measurement only and without a visual feedback function. Second, we conducted a subsequent 6-month phase with noise meters providing direct feedback. Surgeon disturbance during the operation was assessed by a questionnaire after each procedure. ResultsOf the 664 procedures included in this analysis, 447 (67.3%) were in phase 1 and 217 (32.7%) in phase 2. The noise levels in the operating room were decreased by 3.8 dB(A) from 54.6 ± 4.5 dB(A) in phase 1 to 50.8 ± 2.8 dB(A) in phase 2 after intervention with the feedback device (P < .001). During the procedures, there was an increase of 0.7 dB(A) (P < .001), with mean noise levels of 53.5 dB(A) at the beginning of the procedures and 54.2 dB(A) at the end. There was a correlation between the disturbance of the surgeon and the noise level (P < .001). ConclusionThe application of a visual noise warning device in an operating room decreased both the noise levels and surgeon stress and may offer sustained decreases in ambient and peak sound levels, potentially leading to improved quality outcomes in visceral surgery.

Geospatial analysis of environmental noise levels in a residential area in Lagos, Nigeria

AbstractNoise is an inevitable part of daily life and has been identified as a cause of several health deficiencies across the world. It has increasingly become a significant concern on the health and well-being of people. Studies are required to advance knowledge on the sources and impacts of noise in residential neighbourhoods of Lagos State, Nigeria. Therefore, this study assesses the spatial variation of noise levels within a section of the Festac residential area in Lagos in line with noise limits specified by the World Bank Group International Finance Corporation (IFC) Environmental, Health, and Safety (EHS) Guidelines and the Nigerian National Environmental Standards and Regulations Enforcement Agency (NESREA) Noise Standards and Control guidelines for community noise. Data for this research come from a field study comprising measurements of noise levels from 6 observation stations and questionnaire survey with 200 respondents. The criteria for siting the stations was based on factors such as proximity to the roadside, land use and population density, while the questionnaire was administered at random to assess the peoples’ level of awareness on the sources and effects of noise. A digital sound level meter was used to measure noise level variations over a period of 3 weeks for morning, afternoon and evening periods. The measured noise levels were analysed using Analysis of Variance (ANOVA) statistics and the Kriging Geostatistical interpolation technique. Also, logistic regression was used to determine the relationship between the respondents’ perceptions to noise and noise levels. The results indicated that the mean noise levels were within the approximate range of 53.5 – 94.0dBA over the entire period. The highest mean noise levels occurred in the north-western part of the study area where a bus park is present. In general, the noise levels in the area surpass the recommended noise limit of 55dBA, and the logistic regression showed that morning, afternoon and evening mean noise levels were significant predictors of noise variation as perceived by the dwellers. Proper legislation to regulate human activities with respect to noise generation is highly recommended to the local, state and national legislators.

Effectiveness of a visual noise warning system on noise levels in a surgical ICU: A quality improvement programme.

The effects of noise are harmful to patients in the ICU environment, and the latter are particularly noisy places. High noise levels seem to be a factor in sleep disturbance, which can, in turn, result in increased morbidity. High noise levels are a recognised problem in ICUs worldwide. The goal was to estimate the effect of a visual noise-warning system on noise levels in a surgical ICU before and after its implementation. A quality improvement initiative. A 12-bedded surgical ICU in a tertiary care university hospital. A total of 148 adult nonintubated and nonsedated patients completed the study, during a 6-week period. Noise levels were continuously recorded using a Type II sound level meter for 6 weeks. The study was divided into three phases. The first 2 weeks, baseline noise levels were measured (phase I). In week 3 of the study, a visual noise warning system (SoundEar II) that changed colour depending on noise levels within the ICU was installed and implemented (phase II). The alarm system was set to light up green at levels below 55 dBA, orange at levels between 55 and 60 dBA and red at levels above 60 dBA. The device was switched off at the beginning of week 5 and the sound level meter continued recording noise levels for another 2 weeks (phase III). Mean night-time noise level was 55.98 dBA in the preintervention phase, 54.14 dB during the intervention, and 54.98 dBA in the postintervention phase. Mean noise level was reduced statistically significantly by 1.35 dBA, and there was a sustained reduction of 0.86 dBA from the baseline noise level 2 weeks after SoundEar II was switched off. Visual noise warning systems can be effective in achieving a reduction in noise levels in critical care units.

Spatial Analysis of Environmental Noise and Auditory Health of Abeokuta Residents, Ogun State, Nigeria

This study assessed environmental noise levels, mapped the spatial pattern at different times of the day and examined the association with morbidity of auditory ailments in Abeokuta metropolis. The entire metropolis was divided into 80 cells (areas) of 1000 m 2 ; out of which 33 were randomly selected for noise levels assessment. Portable noise meter (AR824) was used to measure noise level and Global Positioning System (Garmin GPS-72H) was employed to take the coordinates of the sample sites for mapping. Risk map of the noise levels were produced using Kriging interpolation techniques based on the spatial spread of measured noise values across the study area. Data on cases of hearing impairments were collected from four major hospitals in the city. Data collected from field measurements and medical records were subjected to descriptive (frequency and percentage) and inferential (Mean, ANOVA and correlation) statistics using SPSS (version 20.0). ArcMap 10.1 was employed for spatial analysis and mapping. Results showed mean noise levels range at morning (42.4±4.14 – 88.2±15.1 dBA), afternoon (45.0±6.72– 86.4±12.5 dBA) and evening (51.0±6.55–84.4±5.19 dBA) across the study area. The interpolated maps identified Kuto, Okelowo, Isale-Igbein and Sapon as high noise risk areas. The monitored noise levels varied significantly among the sampled areas at morning, afternoon and evening (p <0.05). Significant correlation was found between diagnosed cases of auditory ailments and noise levels measured in the morning (r=0.39 at p<0.05). Common auditory ailments found across the metropolis included impaired hearing (25.8%), tinnitus (16.4%) and otitis (15.0%) respectively. Keywords : Abeokuta metropolis, Noise, spatial pattern, auditory impairment

Assessing Potential Health Impacts of Wind Turbine Noise: A Longitudinal Look at Multiple End Points.

Assessing Potential Health Impacts of Wind Turbine Noise: A Longitudinal Look at Multiple End Points.

Sound Level Measurements in Berthing Areas of an Aircraft Carrier

Personnel assigned to aircraft carriers work and live in environments where hazardous noise areas and hearing recovery spaces such as sleeping areas are in close proximity to one another. Hazardous noise exposure occurring during on-duty time periods and elevated noise levels during off-duty periods in sleeping areas may be prohibiting adequate hearing recovery, thus potentially leading to hearing loss and may lead to adverse effects on sleep, leading to crew-member fatigue. This investigation characterizes Equivalent sound level (Leq) and standardized octave band center frequency noise levels according to berthing (sleeping) area location during flight operation and nonflight operation time periods on a US Navy aircraft carrier. In addition, the investigation compares noise measurements in sleeping areas to noise levels associated with auditory rest and poor sleep quality and quantity. Noise levels were measured in berthing areas aboard a US Navy Nimitz-class aircraft carrier during a routine at-sea period. Sixty noise measurements were taken in eight sleeping locations. Leq in decibels 'A' weighted (dBA) and noise levels from 16 to 16 000 Hz in (dB) were measured during flight operations [Leq (flt ops)] and nonflight operations [Leq (nonflt ops)]. Leq was also measured according to sleep area shipboard locations of forward (FWD) Leq (FWD), middle (MID) Leq (MID), and rear (AFT) Leq (AFT). These data were compared to the 70 dBA American Conference of Governmental Industrial Hygienists (ACGIH) threshold limit value (TLV) for effective quiet areas. In addition, these data were compared to noise levels associated with hearing loss and sleep parameters. Statistical analysis was conducted with R version 3.5.2 using an alpha level of 0.05. Leq (flt ops) in sleeping areas was a statistically significant (P < 0.05) 6.4 dBA higher than the Leq (nonflt ops). Leq (FWD) and Leq (MID) in sleeping areas was a statistically significant (P < 0.05) 15.2 and 15.0 dBA higher, respectively, than the Leq (AFT) noise levels. Mean noise levels at standardized center (1/1) octave bands were highest between 500 and 4000 Hz, ranging from 65.2 to 69.8 dB. A total of 72% of all area Leq measurements exceeded the 70 dBA ACGIH TLV classified as effective quiet to allow for temporary threshold shift recovery. All noise measurements exceeded the World Health Organization's noise threshold where adverse effects on sleep begin. Results suggest that sleeping area location in close proximity to relatively high noise sources and activities occurring on an aircraft carrier (i.e. flight operations) increase noise levels in sleeping areas. These findings raise serious concerns since high noise exposures both on duty and during off-duty/sleeping periods may inhibit auditory recovery from hazardous noise exposures. In addition, results suggest noise levels in sleeping areas are high enough to evoke negative sleep effects.

An Assessment of Noise Levels in Sylhet City Corporation, Bangladesh

Noise pollution is a silent villain as it’s quite easy for being ignored by us. Urban areas are more exposed to this deadly agenda as the density of population and their belongings are excessive in there. This study differentiated noise levels of Sylhet City Corporation, a growing city of Bangladesh into different types according to the land use purpose of the city like residential, silent etc. One hundred and sixty-eight noise level readings, taken at 14 different positions during the morning, afternoon, evening, and night of selective weekdays which are categorized as busy days, typical days and weekends were utilized for this research. Results put the average noise level readings in the city centers at between 45 dB(A) and 95 dB (A), dissented from the permissible limits of the World Health Organization (WHO) as well as national standardization organization: Department of Environment (DOE) in all the land use types, with the highest noise pollution levels recorded for transportation, commercial and silent typed areas. The result of the one-way ANOVA test completed where the dependent variable was noise and the independent variable was land use types uncovers a factually huge mean noise levels over the study area (F (4,115) = 9.52, p = 1.1079). Tukey’s HSD method also carried away which showed the uneven difference of noise levels between the land types. The study represents noise pollution auditing, and the immediate needs to control urban noise pollution with convenient and effective policies some of which is recommended at the end of the study.

Audiometric notch for the prediction of early occupational hearing loss and its association with the interleukin-1beta genotype.

ObjectivesNoise-induced hearing loss (NIHL) is a frequent and irreversible industrial-health problem, the early diagnosis of which can prevent hearing deterioration, especially of speech frequencies. This study aimed to assess hearing impairment in workers occupationally exposed to noise. Audiometric notches and IL-1β gene polymorphisms were evaluated.MethodsThe study included 98 workers employed in a textile factory. Pure-tone audiometric testing was conducted for all workers, using a manual pure-tone diagnostic audiometer, and the noise level was measured at four different work sites in a spinning section. IL-1β gene polymorphism was determined using PCR-RFLP methods.ResultsWorkers were exposed to a mean noise level of 105.5 dB. As many as 27.6% of them complained of tinnitus and the majority suffered from some degree of hearing loss in either ear, but none of them exceeded 60 dB. Audiometric notches were detected in either one or both ears. Only 28.6% of workers showed the absence of notches. The TT genotype of IL-1β polymorphisms was dominant in 49% of the workers, whereas TC was predominant in 39.8% and CC in 11.2%. The CC genotype was associated with smoking (54.5%) and audiometric notches (100%). The IL-1β genotype distribution showed no significant difference with or without tinnitus.ConclusionThis study showed an association between the CC genotype and smoking as well as audiometric notches in workers occupationally exposed to noise. Workers showing audiometric notches should be followed up regularly. Further studies are required to confirm the interrelationship amongst tinnitus, audiometric notches, and IL-1β genotypes.

Effect of façade shape and acoustic cladding on reduction of leisure noise levels in a street canyon

Environmental noise is a rising problem in contemporary cities, and the awareness of its consequences on human health is growing. Although the leisure noise generated by people talking in the streets is not generally the most relevant noise source, it has a significant impact in certain urban scenarios, such as nightlife areas. Buildings façades are the primary surfaces upon which the sound emitted within the street is reflected and their design contributes to the reduction of noise level over their fronts. By means of acoustic performance-based design, this research investigates the sound level reduction provided by the shape and the acoustic cladding of an urban façade in front of a talking noise source in a street canyon. The results highlight the screening effect provided by the balconies and the benefits of the application of sound absorbing material on the noise reduction over the façade. Up to 1 dB decrease in the mean level over the entire façade has been achieved with balconies depth of 1.5 m compared to 0.9 m, with a maximum abatement of 2.8 dB at the highest floor. When the entire façade is cladded with sound absorbing material, the mean noise level decrease is up to 10 dB over the façade and up to 3 dB over the opposite one. These reductions are much higher than those obtained by increasing the sound absorption properties of the street paving, that is limited to 1.5 dB averagely, thus underlining the crucial role of façade design in outdoor noise mitigation.

The effect of a quality improvement based on one-meter rule on reducing the noise pollution of surgical intensive care unit

Objective To reduce the noise level of surgical intensive care unit through quality improvement program based on one-meter rule. Methods Measure the status quo of noise level and find out the main noise resources. Implement one-meter rule for three weeks and retest the noise level for a period of seven days. Investigate the satisfaction of medical staff and patients. T-test was performed to compare the noise level and satisfaction. Results The mean noise level were (58.58±0.95) dB before implementation of quality improvement program and was lowered to (55.89±0.92)dB. There was a significant difference(t=4.890, P=0.001). The five time points except eleven o′clock during which the noise levels were over 60 dB decreased significantly after implementation of one-meter rule (t=2.858-6.643, P<0.05). After intervention, satisfaction related to noise level of medical staff and patients scored 10.97±0.93 and 10.63±1.15 respectively, which were higher than before (8.68±1.49, 8.13±1.18) and there were significant differences (t=-11.231,-10.701,P<0.01). Conclusions One-meter rule intervention can decrease the noise level significantly, and increase medical staff′s and patients′ satisfaction, which is worthy of extensive promotion and application. Key words: Noise; Intensive care unit; One-meter rule; Quality improvement program

A Comparative Study between Pre-construction and Construction Phases of Champhai-Zokhawthar Road Construction, Mizoram: Air Quality and Noise Quality Assessments

In recent years, Mizoram has made immense progress in various sectors and initiated developmental programmes for its economic growth. An important contributing factor to this development and growth is the transport connectivity projects. Although connectivity projects can boost economic growth, its negative effects cannot be neglected. In view of this, the present research studies the impacts of Champhai – Zokhawthar road construction on the air quality and noise quality of the region. This comparative study of the impact on the quality of air and noise pollution in the pre-construction phase and construction phase provide a clear-cut example of the negative impacts caused by road construction and provide a fresh outlook for formulation of improved management plans. Air quality assessment was carried out using High Volume Air Sampler and the following parameters were monitored – suspended particulate matter (SPM), respirable suspended particulate matter (RSPM), nitrogen dioxide (NO2) and sulphur dioxide (SO2). The results indicate that mean SPM concentration was increased by 22.82 µg/m3; RSPM concentration by 14.67 µg/m3; NO2 concentration by 4.08 µg/m3; and SO2 concentration was increased by 0.06 µg/m3 from the pre-construction phase to construction phase. Noise quality assessment was carried out at three sites – Zotlang, Melbuk and Zokhawthar by using Lutron SL-4001 Sound Level Meter and Leq, Lmax and Lmin were recorded and calculated. The mean noise level at Zotlang wasincreased by 8.72 dB (A) and at Melbuk the mean noise level was increased by 9.35 dB (A). However, at Zokhawthar, there was a decrease in mean noise level by 0.13 dB (A). From the present study, it is evident that road construction poses a threat to the air quality and noise quality of the study area and improved measuresneed to betaken to curb its negative impacts

Profiling indian classroom listening conditions in schools for children with hearing impairment.

Introduction:An optimal classroom acoustic environment is essential for children with hearing impairment to achieve academic success. The aim of the present study is to provide an overview of classroom listening conditions in schools for children with hearing impairment in a developing country context.Materials and Methods:Noise levels were measured in 37 classrooms from four schools in Chennai, India. Teacher speech levels were measured to obtain classroom speech to noise ratio (SNR) data. The reverberation time was estimated for each classroom.Results:The mean noise level and reverberation time in all classrooms exceeded recommended maximum levels. The measured SNRs were not optimal for children with hearing impairment. Observations of the classrooms revealed that acoustical treatments were inadequate.Conclusion:The results indicated that Indian schools for children with hearing impairment should take steps to improve classroom listening environments. Possible solutions that may alleviate suboptimal classroom sound environments are discussed.

Patterns and trends in OSHA occupational noise exposure measurements from 1979 to 2013

ObjectivesNoise is one of the most common exposures, and occupational noise-induced hearing loss (NIHL) is highly prevalent. In addition to NIHL, noise is linked to numerous non-auditory health effects. The...

AMBIENT NOISE AND NEONATAL HEMODYNAMICS - AN OBSERVATIONAL CROSS-SECTIONAL STUDY

Background: Previous studies reported numerous adverse effects of noise in the newborns such as increase in the heart rate (HR) and respiratory frequency and drop in the oxygen saturation. Objective: The objective of this study was to study the effect of ambient noise levels in neonatal intensive care unit (NICU) on the hemodynamics of neonates. Materials and Methods: This was a hospital-based cross-sectional observational study which aimed at assessing the ambient noise levels in the NICU with a digital decibel meter and its effect on HR, respiratory rate (RR), and oxygen saturation. A total of 105 neonates (both preterm and term) having stable cardiorespiratory status were enrolled in the study. Results: The mean noise level recorded in the NICU was 56.2 dB. The lowest noise level was recorded at 8 am, that is, 46 dB while the highest recorded level was at 2 pm, that is, 65 dB in different areas of the NICU. There was a statistically significant increase in the HR in relation to the noise levels at all times (p 56 dB affected the hemodynamics of the newborn. The maximum increase in the mean HR, RR, and drop in saturation was observed at 2 pm. Staff sensitization and attitude change are needed to decrease the noise pollution in NICU.

Long-term exposure to transportation noise and its association with adiposity markers and development of obesity

The contribution of different transportation noise sources to metabolic disorders such as obesity remains understudied. We evaluated the associations of long-term exposure to road, railway and aircraft noise with measures of obesity and its subphenotypes using cross-sectional and longitudinal designs.We assessed 3796 participants from the population-based Swiss Cohort Study on Air Pollution and Lung and Heart Diseases (SAPALDIA), who attended the visits in 2001 (SAP2) and 2010/2011 (SAP3) and who were aged 29–72 at SAP2. At SAP2 we measured body mass index (BMI, kg/m2). At SAP3 we measured BMI, waist circumference (centimetres) and Kyle body Fat Index (%) and derived overweight, central and general obesity. Longitudinally for BMI, we derived change in BMI, incidence of overweight and obesity and a 3-category outcome combining the latter two. We assigned source-specific 5-year mean noise levels before visits and during follow-up at the most exposed dwelling façade (Lden, dB), using Swiss noise models for 2001 and 2011 and participants' residential history. Models were adjusted for relevant confounders, including traffic-related air pollution.Exposure to road traffic noise was significantly associated with all adiposity subphenotypes, cross-sectionally (at SAP3) [e.g. beta (95% CI) per 10 dB, BMI: 0.39 (0.18; 0.59); waist circumference: 0.93 (0.37; 1.50)], and with increased risk of obesity, longitudinally (e.g. RR = 1.25, 95% CI: 1.04; 1.51, per 10 dB in 5-year mean). Railway noise was significantly related to increased risk of overweight. In cross-sectional analyses, we further identified a stronger association between road traffic noise and BMI among participants with cardiovascular disease and an association between railway noise and BMI among participants reporting bad sleep. Associations were independent of the other noise sources, air pollution and robust to all adjustment sets. No associations were observed for aircraft noise.Long-term exposure to transportation noise, particularly road traffic noise, may increase the risk of obesity and could constitute a pathway towards cardiometabolic and other diseases.

Long-term exposure to road traffic noise and incidence of breast cancer: a cohort study

BackgroundExposure to road traffic noise was associated with increased risk of estrogen receptor (ER)-negative (ER-) breast cancer in a previous cohort study, but not with overall or ER-positive (ER+) breast cancer, or breast cancer prognosis. We examined the association between long-term exposure to road traffic noise and incidence of breast cancer, overall and by ER and progesterone receptor (PR) status.MethodsWe used the data from a nationwide Danish Nurse Cohort on 22,466 female nurses (age > 44 years) who at recruitment in 1993 or 1999 reported information on breast cancer risk factors. We obtained data on the incidence of breast cancer from the Danish Cancer Registry, and on breast cancer subtypes by ER and PR status from the Danish Breast Cancer Cooperative Group, up to 31 December 2012. Road traffic noise levels at the nurses’ residences were estimated by the Nord2000 method between 1970 and 2013 as annual means of a weighted 24 h average (Lden) at the most exposed facade. We used time-varying Cox regression to analyze the associations between the 24-year, 10-year, and 1-year mean of Lden and breast cancer, separately for total breast cancer and by ER and PR status.ResultsOf the 22,466 women, 1193 developed breast cancer in total during 353,775 person-years of follow up, of whom 611 had complete information on ER and PR status. For each 10 dB increase in 24-year mean noise levels at their residence, we found a statistically significant 10% (hazard ratio and 95% confidence interval 1.10; 1.00–1.20) increase in total breast cancer incidence and a 17% (1.17; 1.02–1.33) increase in analyses based on 611 breast cancer cases with complete ER and PR information. We found positive, statistically significant association between noise levels and ER+ (1.23; 1.06–1.43, N = 494) but not ER- (0.93; 0.70–1.25, N = 117) breast cancers, and a stronger association between noise levels and PR+ (1.21; 1.02–1.42, N = 393) than between noise levels and PR- (1.10; 0.89–1.37, N = 218) breast cancers. Association between noise and ER+ breast cancer was statistically significantly stronger in nurses working night shifts (3.36; 1.48–7.63) than in those not working at night (1.21; 1.02–1.43) (p value for interaction = 0.05).ConclusionLong-term exposure to road traffic noise may increase risk of ER+ breast cancer.

Elevated Particulate Matter and Noise Exposure for Spectators at Outdoor Motorsport Events

Since the first recorded steam carriage race in Manchester England, in 1867, motorsport racing has been a globally popular and commercially successful leisure activity. Enthusiasts enjoy a wide range of events, including Formula, stock car, motocross, drag, and many other styles. Despite the many environmental health hazards present at racing events, there have been no published exposure assessment studies for event spectators. To address this knowledge gap, we conducted noise and particulate matter exposure assessment at a series of auto and motocross racing events. Sampling was conducted from May to October, 2017 in designated spectator seating areas at two dirt auto racing tracks, a paved auto racing track, and a dirt motocross track in the St. Louis metro-east region, Illinois, USA, and in Sedalia, Missouri, USA. Using a TSI Instruments SidePak AM520 personal aerosol monitor, arithmetic mean PM2.5 concentration ranged from 51 to 86 µg m-3 across eight race events. Using a Digi-Sense portable sound meter, arithmetic mean noise levels ranged from 75 to 92 dB, and maximum noise levels ranged from 85 to 105 dB across nine race events. PM2.5 at individual race events was combined with 24 hr average concentration data from Illinois EPA&amp;#8217;s Granite City, IL ambient air monitoring sites to obtain time weighted average estimated 24 hour PM2.5 exposure for race spectators. Based on these calculations, 24 hour PM2.5 for race spectators would be 1.8 to 3.5 times local background exposure. These values corresponded to EPA Air Quality Index levels of 63 to 92, falling in the Moderate category, which presents potential respiratory symptoms to highly sensitive individuals. Planned future data collection includes gravimetric sampling, and particle composition analyses. Our results suggest that despite the short duration of these activities, there are possible respiratory hazards from airborne particulate matter exposure for spectators with preexisting vulnerability.