Time-weighted Average Exposure Research Articles

Increase of the indoor concentration of volatile organic compounds after the use of incense and scented candle in studio apartments determined using passive sampling

Burning incenses and scented candles may provide harmful chemicals. Although many studies have evaluated volatile organic chemicals emitted by their use and related health risks, extension of our understanding for guiding appropriate use under various use conditions is necessary. In this study, emission characteristics of commercial incenses and scented candles were evaluated in a laboratory chamber using real-time measurement and the time-weighted average exposure concentrations of monoaromatic compounds and monoterpenes were assessed using passive samplers while volunteers living in a studio apartment use them. After burning incense, the average levels of benzene increased from 1.4 to 100 μg m−3. The presence of a wood core in commercial incense products was the main cause of high benzene emission by burning them although the increase in benzene was also influenced by factors such as the brand of the products, the number of incense sticks burned, the duration of each burning session, and ventilation period. Electrical warming of scented candles increased the levels of monoterpenes by factors of 16–30 on average. Considering the emission characteristics found in this study, exposure to benzene and monoterpenes could be mitigated by cautious use of those products in residential areas.

Film dosimetry for occupant exposure monitoring within Far-UVC installations.

Far-UVC radiation between 200 and 230 nm is a promising technology for reducing airborne disease transmission. Previous work with far-UVC lamps has demonstrated the efficacy of far-UVC radiation to inactivate bacteria and viruses while presenting minimal human health hazards. While far-UVC intentionally exposes the occupied space, effectively disinfecting air between occupants, installations must still ensure that occupant eye and skin exposure is within the recommended daily limits. This study examines far-UVC-sensitive films for measuring the dose received by occupants within two real-world far-UVC installations. The film is characterized for accuracy, angular response, wavelength response, and sources of uncertainty in film response, and used to obtain individual exposure doses that account for both the non-uniform irradiance and the unique motion of individuals within the space. Dosimetry results using the films, which account for the time-weighted average exposure of an occupant, ranged from 10% to 49% of the maximum calculated stationary dose based on peak irradiance measurements. Results from this study spotlight the need to incorporate time-weighted average considerations into the design and safety assessment of far-UVC installations to ultimately operate far-UVC technology with its full potential to prevent the spread of potentially fatal infectious diseases.

Determining occupational exposure to inhalable wood dust in motor manual felling and processing

ABSTRACT The occupational exposure to softwood and hardwood wood dust was determined during forestry work in timber stands. In the determination of inhalable wood dust, three tree species (Fagus sylvatica, Quercus sp. and Pinus brutia) and three chainsaw operating parameters were taken into account (in total six assessment indicators). The first operating parameter was the chainsaw operating under normal conditions (regular chain sharpening). The second and third operating parameters were improper chainsaw maintenance (irregular chain sharpening) and low throttling pressing (operating the chainsaw at low engine speeds), respectively. The determination of inhalable wood dust concentrations from the ambient air was performed using the Inhalable Organic Matter (IOM) sampler, manufactured by SKC Button Sampler (Dorset, United Kingdom). Out of a total of 108 concentration cases of inhalable wood dust, 44 (40.74%) showed concentrations greater than 3.00 mg·m−3, while in 10 (9.26%) cases, the dust concentration exceeded 5 mg·m−3. The eight-hour time-weighted average exposure to wood dust ranged from 0.99 mg·m−3 to 12.52 mg·m−3, with an average of 4.22 mg·m−3. The results indicated that the increase in wood dust concentration was dependent on improper chainsaw maintenance, while low throttling pressing reduces dust concentration levels. Additionally, an increase in wood dust concentration was observed in species with thick bark (Pinus brutia and Quercus petraea).

Long-term exposure to transportation noise in relation to global cognitive decline and cognitive impairment: Results from a Swedish longitudinal cohort

Background and aimsTransportation noise is an environmental exposure with mounting evidence of adverse health effects. Besides the increased risk of cardiovascular and metabolic diseases, recent studies suggest that long-term noise exposure might accelerate cognitive decline in older age. We examined the association between transportation noise and cognitive function in a cohort of older adults. MethodsThe present study is based on 2594 dementia-free participants aged 60 + years from the Swedish National study on Aging and Care in Kungsholmen (SNAC-K). Global cognition score and CIND (cognitive impairment, no dementia) were assessed with a comprehensive neuropsychological battery at baseline and up to 16 years. Residential transportation noise resulting from road traffic, railway, and aircraft were estimated at the most exposed façade and the time-weighted average exposure was assessed. Linear mixed-effect models were used to assess the effect of long-term traffic noise exposure on the rate of change in global cognition score. Hazard ratios (HRs) and 95 % confidence intervals (CIs) of CIND by transportation noise exposure were obtained with Cox proportional hazard models. ResultsGlobal cognition score decreased at an average rate of −0.041 (95 %CI −0.043, −0.039) per year. Aircraft noise was associated with a 0.007 (per 10 dB Lden; 95 %CI −0.012, −0.001) faster annual rate of decline. Global cognition score seems to be not affected by road traffic and railway noise. During the follow-up, 422 (21 %) participants developed CIND. A 10-dB Lden difference in exposure to aircraft and railway noise was associated with a 16 % (HR 1.16, 95 %CI 0.91, 1.49) and 26 % (HR 1.26, 95 %CI 1.01, 1.56) increased hazard of CIND in the multi-pollutant model, respectively. No association was found for road traffic (HR 1.00, 95 %CI 0.83, 1.21). ConclusionsTransportation noise was linked to cognitive impairment and faster cognitive decline among older adults. Future studies are warranted to confirm our results.

Analysis of respirable dust exposure data collected at a Zambian copper mine between 2017 and 2022.

Mine workers are occupationally exposed to respirable dust, which can cause irreversible lung diseases and controlling exposure concentrations to as low as reasonably practicable is, therefore, essential. To implement exposure reduction strategies and adequately manage exposure to hazardous chemicals, exposure needs to be measured and recorded according to a standard exposure management plan. This study aimed to assess the available respirable dust exposure data measured between 2017 and 2022 in various work areas and job categories at two mining shafts and a concentrator plant of a Zambian copper mine. Additionally, the monitoring program implemented at the mine was assessed for appropriateness. Descriptive data analysis was used to create an exposure matrix comprising 253 exposure measurements. Approximately 5.6% of the measured concentrations exceeded the South African time-weighted average occupational exposure limit (TWA-OEL) of 3 mg/m3. The geometric means of respirable dust exposure for shaft A, shaft B and the concentrator plant were 0.44 mg/m3, 0.44 mg/m3, and 0.68 mg/m3, respectively. The work areas with the highest maximum exposure results were the tipping area (18.0 mg/m3) at shaft A, the sump and waste bin (8.05 mg/m3) at shaft B and the screening (10.8 mg/m3), secondary crusher (14.0 mg/m3), foreign ore bin (4.43 mg/m3), and tertiary crusher (5.07 mg/m3) areas at the concentrator plant. It was found that the monitoring strategy implemented at the mine was flawed and did not collect a sufficient number of samples in each area during each year to make rigorous statistical assessment possible. This study highlights the sampling strategy's shortcomings and recommends adopting a standardized monitoring strategy, such as EN689, to improve the respirable dust monitoring program at the mine. Additionally, this strategy can be implemented across Zambia and, if implemented correctly, it has the potential to be improve exposure monitoring across the country as no standard sampling strategy is currently enforced by the Government.

Household air pollution and risk of pulmonary tuberculosis in HIV-Infected adults

BackgroundIn low- and middle-income countries countries, millions of deaths occur annually from household air pollution (HAP), pulmonary tuberculosis (PTB), and HIV-infection. However, it is unknown whether HAP influences PTB risk among people living with HIV-infection.MethodsWe conducted a case-control study among 1,277 HIV-infected adults in Bukavu, eastern Democratic Republic of Congo (February 2018 – March 2019). Cases had current or recent (<5y) PTB (positive sputum smear or Xpert MTB/RIF), controls had no PTB. Daily and lifetime HAP exposure were assessed by questionnaire and, in a random sub-sample (n=270), by 24-hour measurements of personal carbon monoxide (CO) at home. We used multivariable logistic regression to examine the associations between HAP and PTB.ResultsWe recruited 435 cases and 842 controls (median age 41 years, [IQR] 33-50; 76% female). Cases were more likely to be female than male (63% vs 37%). Participants reporting cooking for >3h/day and ≥2 times/day and ≥5 days/week were more likely to have PTB (aOR 1·36; 95%CI 1·06-1·75) than those spending less time in the kitchen. Time-weighted average 24h personal CO exposure was related dose-dependently with the likelihood of having PTB, with aOR 4·64 (95%CI 1·1-20·7) for the highest quintile [12·3-76·2 ppm] compared to the lowest quintile [0·1-1·9 ppm].ConclusionTime spent cooking and personal CO exposure were independently associated with increased risk of PTB among people living with HIV. Considering the high burden of TB-HIV coinfection in the region, effective interventions are required to decrease HAP exposure caused by cooking with biomass among people living with HIV, especially women.

Longitudinal Control of Lipid Levels in Patients With Premature Coronary Artery Disease

BackgroundLipid-lowering therapy (LLT) is a central aspect of the treatment of patients with coronary artery disease (CAD), and the benefits of LLT accrue over time. However, there are limited real-world data on longitudinal lipid control in patients with premature CAD. ObjectivesThe purpose of this study was to assess longitudinal attainment of guideline-recommended lipid goals and outcomes in a contemporary cohort of patients with premature CAD. MethodsWe enrolled males younger than 50 years and females younger than 55 years with coronary stenosis of >50% and examined achievement of lipid goals, LLT characteristics, and cardiovascular outcomes (major adverse cardiovascular event [MACE]). ResultsOf 476 patients who presented with acute coronary syndrome (ST-elevation myocardial infarction, non-ST-segment elevation myocardial infarction, unstable angina) (68%), stable angina (28%), or other symptoms, 73.2% achieved low-density lipoprotein cholesterol (LDL-C) <1.8 mmol/L on at least 1 occasion, but only 27.3% consistently stayed in the target range for 3 years after diagnosis. Although 73.9% of patients received high-intensity LLT at the time of diagnosis, only 43.5% had good adherence over the following 3 years. In multivariable analysis, 1 mmol/L increase in time-weighted average exposure to LDL-C, but not the lowest achieved LDL-C, was associated with a higher risk of MACE, hazard ratio 2.02 (95% CI: 1.48-2.76), when adjusted for sex, age, hypertension, diabetes, and smoking. ConclusionsWe found low rates of longitudinal lipid target achievement in patients with premature CAD. Cumulative LDL-C exposure, but not lowest achieved LDL-C, was associated with risk of MACE. This highlights the critical importance of longitudinal control of lipids levels and identifies opportunities to improve LLT and maximize the time-dependent benefits of lipid-lowering.

Joint association of air pollution exposure and inflammation-related proteins in relation to infant lung function

Background and aimSystemic inflammation is one potential mechanism underlying negative impact of air pollution on lung function. Levels of inflammation-related proteins have the potential to characterize infants’ susceptibility to air pollution induced lung function impairment. This study aimed to examine the interplay between air pollution exposure and inflammation-related proteins on lung function in 6-months-old infants. MethodsIn the EMIL birth cohort from Stockholm (n = 82), dynamic spirometry, along with measurement of plasma levels of 92 systemic inflammation-related proteins (Olink Proseek Multiplex Inflammation panel) have been carried out in infants aged six months. Time-weighted average exposure to particles with an aerodynamic diameter of <10 μm (PM10), <2.5 μm (PM2.5), and nitrogen dioxide (NO2) at residential addresses from birth and onwards was estimated via validated dispersion models. To characterize the abnormality of inflammation-related protein profile, for each protein in each infant, we calculated the relative deviance of the protein level from age- and sex-specific median in terms of its age- and sex-specific interquartile range (IQR), followed by computing the absolute value of the smallest relative deviance, “minimum absolute deviance”. Using linear regression models, interaction of air pollution and the abnormal inflammatory profile on lung function was estimated on the additive scale. ResultsWe found joint association of PM exposure and an abnormal inflammatory protein profile in relation to FEV0.5 and FVC. For 0.1 unit increase in minimum absolute deviance, one IQR increase in PM10 was associated with 85.9 ml (95% CI: −122.9, −48.9) additional decrease in FEV0.5, and 72.3 ml (95% CI: −121.5, −23.2) additional decrease in FVC. Similar results were obtained with PM2.5 exposure, while less apparent for NO2. ConclusionsEarly life air pollution exposure and abnormal inflammation-related protein profiles may interact synergistically towards lower lung function in infants.

Concomitant exposure to air pollution, green space and noise, and risk of myocardial infarction: a cohort study from Denmark.

The three correlated environmental exposures (air pollution, road traffic noise, and green space) have all been associated with the risk of myocardial infarction (MI). The present study aimed to analyse their independent and cumulative association with MI. In a cohort of all Danes aged 50 or older in the period 2005-17, 5-year time-weighted average exposure to fine particles (PM2.5), ultrafine particles, elemental carbon, nitrogen dioxide (NO2), and road traffic noise at the most and least exposed façades of residence was estimated. Green space around residences was estimated from land use maps. Cox proportional hazard models were used to estimate hazard ratios (HRs) and 95% confidence interval (CI), and cumulative risk indices (CRIs) were calculated. All expressed per interquartile range. Models were adjusted for both individual and neighbourhood-level socio-demographic covariates. The cohort included 1 964 702 persons. During follow-up, 71 285 developed MI. In single-exposure models, all exposures were associated with an increased risk of MI. In multi-pollutant analyses, an independent association with risk of MI was observed for PM2.5 (HR: 1.026; 95% CI: 1.002-1.050), noise at most exposed façade (HR: 1.024; 95% CI: 1.012-1.035), and lack of green space within 150 m of residence (HR: 1.018; 95% CI: 1.010-1.027). All three factors contributed significantly to the CRI (1.089; 95% CI: 1.076-1.101). In a nationwide cohort study, air pollution, noise, and lack of green space were all independently associated with an increased risk of MI. The air pollutant PM2.5 was closest associated with MI risk.

The use of face masks to reduce inhalation exposure to reactive disinfectants

Following the COVID-19 pandemic, the use of face masks has become a “new norm” to avoid contagion. Although masks are effective in reducing aerosol transmission, including that of virus particles, studies on the effect of face masks on inhalation exposure to toxic substances are scarce. This study first reports that wearing fabric face masks reduces the inhalation of reactive chlorine gas generated from chlorine disinfectants. Effective chlorine concentrations both inside and outside masks while using a consumer product were compared quantitatively by two methods: real-time measurement using proton transfer reaction time-of-flight mass spectrometry and time-weighted average exposure concentration measured by passive air sampling. Chlorine gas levels within masks were significantly lower than those outside masks; this reduction was not as apparent for the two representative volatile organic compounds, ethylbenzene and trichloroethylene. Notable exposure reduction by wearing face masks was confirmed by a consumer panel of ten people carrying out routine bathroom clean-up. This result suggests that face masks may be a universal and cost-effective tool to reduce respiratory exposure to reactive harmful chemicals.

Noise Exposure and Hearing Loss among Workers at a Hammer Forge Company.

The National Institute for Occupational Safety and Health (NIOSH) evaluated continuous and impact noise exposures and hearing loss among workers at a hammer forge company. Full-shift personal noise exposure measurements were collected on forge workers across 15 different job titles; impact noise characteristics and one-third octave band noise levels were assessed at the forge hammers; and 4,750 historic audiometric test records for 483 workers were evaluated for hearing loss trends. Nearly all workers' noise exposures exceeded regulatory and/or recommended exposure limits. Workers working in jobs at or near the hammers had full-shift time-weighted average noise exposures above 100 decibels, A-weighted. Impact noise at the hammers reached up to 148 decibels. Analysis of audiometric test records showed that 82% of workers had experienced a significant threshold shift, as defined by NIOSH, and 63% had experienced a standard threshold shift, as defined by the Occupational Safety and Health Administration (OSHA). All workers with an OSHA standard threshold shift had a preceding NIOSH significant threshold shift which occurred, on average, about 7 years prior. This evaluation highlights forge workers' exposures to high levels of noise, including impact noise, and how their hearing worsened with age and length of employment.

Associations of time-weighted individual exposure to ambient particulate matter with carotid atherosclerosis in Beijing, China

BackgroundTime-location information (time spent on commuting, indoors and outdoors around residential and work places and physical activity) and infiltrated outdoor pollution was less considered estimating individual exposure to ambient air pollution. Studies investigating the association between individual exposure to particulate matter (PM) with aerodynamic diameter < 10 μm (PM10) and < 2.5 μm (PM2.5) and carotid atherosclerosis presented inconsistent results. Moreover, combined effect of pollutants on carotid atherosclerosis was not fully explored. We aimed to investigate the association between long-term individual time-weighted average exposure to PM2.5 and PM10 and the risk of carotid atherosclerosis, and further explore the overall effect of co-exposure to pollutants on carotid atherosclerosis.MethodsThe study population included 3069 participants derived from the Beijing Health Management Cohort (BHMC) study. Daily concentration of ambient air pollutants was estimated by land-use regression model at both residential and work addresses, and one- and two-year time-weighted average individual exposure was calculated by further considering personal activity pattern and infiltration of ambient air pollution indoors. We explored the association of PM2.5 and PM10 with carotid atherosclerosis and pooled the overall effect of co-exposure to ambient air pollutants by quantile g-computation.ResultsA significant association between time-weighted average exposure to PM2.5 and PM10 and carotid atherosclerosis was observed. Per interquartile range increase in two-year exposure to PM2.5 (Hazard ratio (HR): 1.322, 95% confidence interval (CI): 1.219–1.434) and PM10 (HR:1.213, 95% CI: 1.116–1.319) showed the strongest association with carotid atherosclerosis, respectively. Individuals in higher quartiles of pollutants were at higher risk for carotid atherosclerosis compared with those in the lowest quartile group. Concentration response functions documented the nearly linear and nonlinear relationship and interpreted the upward trends of the risk for carotid atherosclerosis with increasing level of pollutant concentrations. Moreover, effect estimates for the mixture of pollutants and carotid atherosclerosis were larger than any of the individual pollutants (HR (95% CI) was 1.510 (1.338–1.704) and 1.613 (1.428–1.822) per quartile increase for one-year and two-year time-weighted average exposure, respectively).ConclusionsIndividual time-weighted average exposure to PM2.5 and PM10 was associated with carotid atherosclerosis. Co-exposure to ambient air pollution was also positively associated with carotid atherosclerosis.

Assessment of silicone wristbands for monitoring personal exposure to chlorinated paraffins (C8-36): A pilot study

Chlorinated paraffins (CPs) are a major environmental concern due to their ubiquitous presence in the environment. Since human exposure to CPs can significantly differ among individuals, it is essential to have an effective tool for monitoring personal exposure to CPs. In this pilot study, silicone wristbands (SWBs) were employed as a personal passive sampler to measure time-weighted average exposure to CPs. Twelve participants were asked to wear a pre-cleaned wristband for a week during the summer of 2022, and three field samplers (FSs) in different micro-environments were also deployed. The samples were then analyzed for CP homologs by LC-Q-TOFMS. In worn SWBs, the median concentrations of quantifiable CP classes were 19 ng/g wb, 110 ng/g wb, and 13 ng/g wb for ∑SCCPs, ∑MCCPs, and ∑LCCPs (C18-20), respectively. For the first time, lipid content is reported in worn SWBs, which could be a potential impact factor in the kinetics of the accumulation process for CPs. Results showed that micro-environments were key contributors to dermal exposure to CPs, while a few outliers suggested other sources of exposure. CP exposure via dermal contact showed an increased contribution and thus poses a nonnegligible potential risk to humans in daily life. Results presented here provide proof of concept of the use of SWBs as a cheap and non-invasive personal sampler in exposure studies.

Long-term exposure to low-level arsenic in drinking water is associated with cause-specific mortality and hospitalization in the Mt. Amiata area (Tuscany, Italy)

BackgroundArsenic in drinking water is a global public health concern. This study aims to investigate the association between chronic low-level exposure to arsenic in drinking water and health outcomes in the volcanic area of Mt. Amiata in Italy, using a residential cohort study design.MethodsChronic exposure to arsenic in drinking water was evaluated using monitoring data collected by the water supplier. A time-weighted average arsenic exposure was estimated for the period 2005–2010. The population-based cohort included people living in five municipalities in the Mt. Amiata area between 01/01/1998 and 31/12/2019. Residence addresses were georeferenced and each subject was matched with arsenic exposure and socio-economic status. Mortality and hospital discharge data were selected from administrative health databases. Cox proportional hazard models were used to test the associations between arsenic exposure and outcomes, with age as the temporal axis and adjusting for gender, socio-economic status and calendar period.ResultsThe residential cohort was composed of 30,910 subjects for a total of 407,213 person-years. Analyses reported risk increases associated with exposure to arsenic concentrations in drinking water > 10 µg/l for non-accidental mortality (HR = 1.07 95%CI:1.01–1.13) and malignant neoplasms in women (HR = 1.14 95%CI:0.97–1.35). Long-term exposure to arsenic concentrations > 10 µg/l resulted positively associated with several hospitalization outcomes: non-accidental causes (HR = 1.06 95%CI:1.03–1.09), malignant neoplasms (HR = 1.10 95%CI:1.02–1.19), lung cancer (HR = 1.85 95%CI:1.14–3.02) and breast cancer (HR = 1.23 95%CI:0.99–1.51), endocrine disorders (HR = 1.13 95%CI:1.02–1.26), cardiovascular (HR = 1.12 95%CI:1.06–1.18) and respiratory diseases (HR = 1.10 95%CI:1.03–1.18). Some risk excesses were also observed for an exposure to arsenic levels below the regulatory standard, with evidence of exposure-related trends.ConclusionsOur population-based cohort study in the volcanic area of Mt. Amiata showed that chronic exposure to arsenic concentrations in drinking water above the current regulatory limit was associated with a plurality of outcomes, in terms of both mortality and hospitalization. Moreover, some signs of associations emerge even at very low levels of exposure, ​​below the current regulatory limit, highlighting the need to monitor arsenic concentrations continuously and implement policies to reduce concentrations in the environment as far as possible.

The effect of mask fit test on the association between the concentration of metals in biological samples and the results of time-weighted average personal exposure: A study on Japanese male welders.

The mask fit test confirms whether the wearing condition of the wearer's face and the facepiece of the respirators are used appropriately. This study aimed to examine whether the results of the mask fit test affect the association between the concentration of metals related to welding fumes in biological samples and the results of time-weighted average (TWA) personal exposures. A total of 94 male welders were recruited. Blood and urine samples were obtained from all participants to measure the metal exposure levels. Using personal exposure measurements, the 8-h TWA (8 h-TWA) of respirable dust, TWA of respirable Mn, and 8-h TWA of respirable Mn were calculated. The mask fit test was performed using the quantitative method specified in the Japanese Industrial Standard T8150:2021. Fifty-four participants (57%) passed the mask fit test. Only in the Fail group of the mask fit test, it was observed that blood Mn concentrations be positively associated with the results of TWA personal exposure after adjusting for multivariate factors (8-h TWA of respirable dust; coefficient, 0.066; standard error (SE), 0.028; P = 0.018, TWA of respirable Mn: coefficient, 0.048; SE, 0.020; P = 0.019, 8 h-TWA of respirable Mn: coefficient, 0.041; SE, 0.020; P = 0.041). The results clarify that welders with high concentrations of welding fumes in their breathing air zone are exposed to dust and Mn if there is leaking air owing to the lack of fitness between respirators and the wearer's face when using human samples in Japan.

Evaluation of occupational exposure to wood dust among sawmill workers within the Gert Sibande District Municipality, South Africa.

Wood dust is regarded as one of the human carcinogen based on an increased risk of nasal and sinonasal cancer. This study was conducted in two sawmills to measure and determine the time-weighted average (TWA) exposure level to wood dust, and compare the results with the South African occupational exposure limit (OEL). Personal and area respirable and total inhalable wood dust samples were collected using calibrated Giliair-3 personal air sampling pump (Sensidyne, USA). Data was analysed using Microsoft Office Excel 2019 Analysis Tool Pak for a summary of descriptive statistics. Both the geometric means and standard deviation as well as the minimum and maximum values were calculated. The geometric mean = GM (geometric standard deviation = GSD) for personal respirable wood dust exposure at sawmill A was 0.9(4.8) mg/m3 while at sawmill B - 0.57(0.75) mg/m3. The GM(GSD) for personal total inhalable wood dust exposure at sawmill A was 0.37(0.94) mg/m3 while at sawmill B - 1.19(16.91) mg/m3. Besides that, the GM(GSD) for area respirable wood dust at sawmill A was 0.13(0.09) mg/m 3 , while at sawmill B - 0.8(0.6) mg/m3. Likewise, the GM(GSD) for area total inhalable wood dust at sawmill A was 0.13(0.16) mg/m3 while at sawmill B - 0.54(0.55) mg/m3 . Results for the majority of samples were below the OEL. Workers smoking tobacco or cigarettes should be encouraged to stop smoking since smoking, especially when associated with exposure to wood dust, may increase the risk of respiratory health symptoms.

Traffic noise in relation to markers of obesity in nine Nordic cohorts

Background and aims: Evidence suggests that transportation noise may increase the risk of obesity. However, there are uncertainties regarding e.g. exposure-response relations, potential threshold effects and interactions, in particular with air pollution. In this study, we aim to assess the exposure-response associations between residential exposure to road traffic noise and Body Mass Index (BMI), overweight and obesity, as well as to investigate interaction with air pollution (PM₂.₅). Methods: The study was based on pooled analyses of nine cohorts from Denmark and Sweden, including 128 000 subjects, recruited 1990–2004. Road traffic noise was calculated as time-weighted average Lden exposure five years prior to the baseline of each cohort. Linear and logistic regression models were used to assess associations with BMI and overweight (BMI &amp;#x2265;25 kg/m²) and obesity (BMI &amp;#x2265;30 kg/m²), respectively, adjusting for individual and area-based demographic, socio-economic, lifestyle and environmental factors. Exposure-response relationships were assessed using restricted cubic splines. Results: In the fully adjusted model, exposure to road traffic noise was associated with an increased BMI of 0.07 kg/m² (95% confidence interval, 95% CI, 0.03–0.10) per 10 dB Lden, as well as with an excess risk of being overweight, odds ratio (OR) 1.03 (95% CI 1.01–1.05), or obese, OR 1.06 (95% CI 1.03–1.09). There appeared to be a threshold around 50–55 dB Lden in the exposure-response relationship for BMI. Furthermore, stronger associations were suggested at levels above the mean PM2.5 (15 µg/m³): 3rd quartile 0.11 kg/m² (95% CI 0.04–0.17) and 4th quartile 0.22 kg/m² (95% CI 0.16–0.28). Conclusions: Preliminary findings from this study indicate positive associations between road traffic noise and BMI as well as with overweight and obesity. Stronger associations appeared at noise levels above 50–55 dB Lden and at higher PM₂.₅ levels. Keywords: Road traffic noise, BMI, overweight, obesity, exposure-response function, interaction

Ambient air pollution and inflammation-related proteins during early childhood

Background and aimExperimental studies show that short-term exposure to air pollution may alter cytokine concentrations. There is, however, a lack of epidemiological studies evaluating the association between long-term air pollution exposure and inflammation-related proteins in young children. Our objective was to examine whether air pollution exposure is associated with inflammation-related proteins during the first 2 years of life. MethodsIn a pooled analysis of two birth cohorts from Stockholm County (n = 158), plasma levels of 92 systemic inflammation-related proteins were measured by Olink Proseek Multiplex Inflammation panel at 6 months, 1 year and 2 years of age. Time-weighted average exposure to particles with an aerodynamic diameter of <10 μm (PM10), <2.5 μm (PM2.5), and nitrogen dioxide (NO2) at residential addresses from birth and onwards was estimated via validated dispersion models. Stratified by sex, longitudinal cross-referenced mixed effect models were applied to estimate the overall effect of preceding air pollution exposure on combined protein levels, “inflammatory proteome”, over the first 2 years of life, followed by cross-sectional protein-specific bootstrapped quantile regression analysis. ResultsWe identified significant longitudinal associations of inflammatory proteome during the first 2 years of life with preceding PM2.5 exposure, while consistent associations with PM10 and NO2 across ages were only observed among girls. Subsequent protein-specific analyses revealed significant associations of PM10 exposure with an increase in IFN-gamma and IL-12B in boys, and a decrease in IL-8 in girls at different percentiles of proteins levels, at age 6 months. Several inflammation-related proteins were also significantly associated with preceding PM10, PM2.5 and NO2 exposures, at ages 1 and 2 years, in a sex-specific manner. ConclusionsAmbient air pollution exposure influences inflammation-related protein levels already during early childhood. Our results also suggest age- and sex-specific differences in the impact of air pollution on children's inflammatory profiles.

Assessment of semen quality of taxi drivers exposed to whole body vibration

Whole body vibration (WBV) is a recognized occupational hazard for many workers such as drivers and operators of heavy and light machinery and exposure to it is accompanied by physical and mental repercussions. Only the limited studies have been done on the effects of vibration exposure on reproductive indices, however vibration exposure has been indicated as being a hazardous agents with the potential of being able to directly affect the reproductive system. Considering the importance of infertility, the present study was conducted with the aim of investigating semen quality among taxi drivers in Tehran and determine the effect of exposure to WBV on sperm parameters. The study population consisted of 70 taxi drivers and 70 office employee who attended infertility clinics for diagnostic purposes in the past year. The participants had to meet the entry criteria of the study while also being willing to recruit. Data was collected in the form of demographic questionnaires and general health questionnaires as well as sperm analysis conducted in an infertility clinic according to standard laboratory guidelines. The 8-hour time-weighted average (TWA) exposure to of WBV in automobile was measured as per ISO 2631-1. The TWA exposure to WBV among the taxi drivers and office employees were 0.697 ± 0.13 m/s2 and 0.068 ± 0.09 m/s2 respectively (P < 0.05). A statistically significant difference in total sperm count, progressive motility, non-progressive motility and total motility was observed between the taxi drivers and the office employees (P < 0.05). According to the univariate analysis of variance, exposure to WBV had negative effect on sperm concentration, progressive motility and normal morphology (P > 0.05); moreover exposure to WBV resulted in the larger effect size (B) on sperm parameters than the demographic variables (P > 0.05). Being taxi drivers increase the chance of the decreased semen quality (P > 0.05). It is difficult to draw definitive conclusions regarding the effects of WBV while intervening factors exist, such as psychological stressors, quality of sleep, background issues as well as environmental factors such as chemical pollutants (heavy metals) or ergonomic factors (body posture and working while sitting down).

Occupational noise exposure of utility workers using task based and full shift measurement comparisons

IntroductionThe main purpose of this study was to determine if a combination of area noise measurements and task activity diaries give a reasonable estimate of full-shift dosimeter measurements in a cohort of utility workers. Few studies have been conducted to evaluate the efficacy of using task-based noise exposures to estimate full shift time weighted average (TWA) noise exposures. MethodsEstimates of full shift time TWA noise exposures for a group of utility workers (n = 224) were calculated using dosimeter measurements. Area noise measurements using a sound level meter were used to recreate the TWA for each personal dosimetry sample based on detail provided in the task activity diary for each sample. Full shift TWA noise exposures were compared to corresponding area noise measurements using simple linear regression analysis. ResultsAssociations between full shift TWA measurements and task-based area measurements were closely associated, with R2 values above 0.85 for all job roles. DiscussionTask-based noise exposure analysis has the potential to be widely used in the utilities industry. While full-shift monitoring to determine TWA exposures is useful, the changing work environment, variability in tasks and equipment, and varying workday hours, limit the ability of the 8-hr TWA to accurately characterise the exposures and associated health risks for utility workers.